DOWNHOLE TOOL HAVING CONE SUPPORTED INSERTS WITH SERIAL WIDE TEETH

Description

RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. Patent Application No. 63/658,737, filed on Jun. 11, 2024, U.S. Patent Application No. 63/708,340, filed on Oct. 17, 2024, and U.S. Patent Application No. 63/763,031, filed on Feb. 25, 2025. All of these prior applications are herein incorporated by reference in their entirety.

TECHNICAL FIELD

The disclosure generally pertains to downhole tools used in oil and gas industry wells that engage a surrounding casing or tubular. The scope of the disclosure, however, is not limited to such tools, industries, and uses.

BACKGROUND

Settable downhole tools temporarily or permanently isolate zones in a casing, tubular, or other adjacent surfaces. Settable downhole tools used in oil and gas industry wells include frac plugs, bridge plugs, packers, and other tools that grip surrounding casing, tubular, or other adjacent surfaces. For convenience, settable downhole tools are collectively referred to as “downhole tools,” and surrounding casing, tubular, or other adjacent surfaces are collectively referred to as “casing.” Downhole tools may have a slip assembly comprised of a slip and a cone, both disposed on the downhole tool's mandrel and adjacent to each other. The cone has an incline on its outer face relative to the mandrel and facing toward the slip. The slip has a similar matching incline on its inner face toward the cone. The slip may include a slip body with multiple slip pads and slip buttons or other inserts disposed in the slip pads. An insert comprises an inner element located within the slip body for holding the insert within the slip body and end outer gripping element that protrudes outside the slip body's outer surface. The outer gripping element is configured to engage the inner face of the surrounding casing when setting the downhole tool forces the slip body with its inserts outward against the inner wall of the casing.

In operation, setting the downhole tool compresses the slip and cone along the mandrel toward one another. This forces the slip up the cone's incline, radially outward away from the mandrel and toward the casing. Forcing the slip toward the casing forces the slip's inserts to engage, penetrate, and hold the downhole tool against the casing. This insert/inner wall engagement holds the downhole tool to the casing during downhole operations, which may be temporary or permanent.

United States patent Publication No. 2019/0063178 provides relevant background information, teaches various slip and insert designs and combinations, and is fully incorporated herein by reference as if fully copied herein.

SUMMARY

A downhole tool slip assembly having inserts with serial wide axial teeth on a long, wide shelf embedded in a slip pad. The insert's base extends to the cone, is thinner than the teeth and shelf, and has an axial groove to facilitate drilling it out. Inner slip pad fingers sliding within cone grooves and guidance fins adjacent to slip pad connections reliably separate slip pads and deter slip rotation. The insert's teeth are wider than the insert's base, and a tooth shelf embedded in the slip body's outer surface securely holds the insert. The slip body is configured to accept and maintain the slip insert. The tooth shelf embedded in the slip body's outer surface, the extended insert base, and the radial pressure on the insert due to being directly squeezed between the cone and casing combine to securely hold the insert in the slip against being rolled out, twisted out, or sheared during setting of the downhole tool or downhole operations. Slip inner face fingers fit within corresponding cone outer face grooves, and guidance lugs between slip segments deter slip rotation of the slip about the cone, further protecting the insert/cone engagement against disengagement.

In an embodiment, the insert's base extends fully through the slip body, from the insert's teeth to against the cone, so the insert's bottom will slide against the outward-facing inclined face of the expansion cone to expand the slip/insert/teeth toward the inner face of the casing when the tool is being set in the casing. During the setting of the downhole tool, the slip is vertically compressed toward the center of the downhole tool along the cone's outer surface. The bottom of the insert is directly against the cone, so axial movement of the insert along the outward-facing incline face of the cone directly expands the insert's teeth against the inner face of the casing. Because the cone and the insert are incompressible relative to many conventional slips, the direct cone to insert to casing structure creates a dependable direct transfer of force between the cone and the insert's teeth.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first exemplary downhole tool 1.

FIG. 2 shows a perspective view of an embodiment of insert 11.

FIG. 3 shows a different perspective view of Insert 11.

FIG. 4 shows a side cross-section view of insert 11 and teeth 12a-g.

FIG. 5 shows insert 11 viewed from its back face 18.

FIG. 6 shows an embodiment of insert 11 from underneath insert 11.

FIG. 6A shows a view of insert 11's base right channels 19a-c and base left channels 21a-c, interfacing with right pocket ridges 62a-c and left pocket ridges 63a-c.

FIG. 7 shows an axial view of lower slip 10 from the lower end of mandrel 2.

FIG. 7A shows a side view of lower slip body 34.

FIG. 8 shows a cross-sectional view of slip body 34.

FIG. 9 shows section A-A of FIG. 7's slip body 34.

FIG. 10 shows section B-B of FIG. 7's slip body 34.

FIG. 11 shows an upper perspective view of slip body 34.

FIG. 12 shows a lower perspective view of slip body 34.

FIG. 13 shows a perspective view of lower cone 66.

FIG. 14 shows a side cutaway view of lower cone 66.

FIG. 15 shows a top-down view of lower cone 66.

FIG. 16 shows a view of cone upper base 68 from above lower cone 66.

FIG. 17 shows a perspective view of an insert embodiment, namely insert 11a.

FIG. 18 shows a top-down view of insert 11.

FIG. 19 shows a view from underneath insert 11.

FIG. 20 shows a side view of slip body 34.

FIG. 21 shows an axial view of cone 34.

FIG. 22 shows a cross-sectional view of cone 34.

FIG. 23 shows a perspective view of lower cone 66.

FIG. 24 shows a top-down view of lower cone 66.

FIG. 25 shows cavities 25a and 25b within insert base 18a.

FIG. 26 shows cavities 27a and 27b within insert base 18b.

FIG. 27 shows an alternative insert base 18c.

FIG. 28 shows an alternative insert base 18d.

FIG. 29 shows an alternative embodiment of downhole tool number 1.

FIG. 30 shows an alternative embodiment of downhole tool number 1.

FIG. 31 shows first groove 183 on first base side 185 of base 196.

FIG. 32 shows first groove 183 on first base 185 and second groove 193 on second base face 195.

FIG. 33 shows a side view of insert 181 showing first groove 183 on first base face 185.

FIG. 34 shows an embodiment of downhole tool 200.

FIG. 35 shows an embodiment of downhole tool 200.

FIG. 36 shows first slip pad 260 and second slip pad 262 separated by axial channel 264.

DETAILED DESCRIPTION

For descriptive purposes, “upper,” “upward,” and like terms reference the direction along the downhole tool's mandrel 2 toward top ring 3. “Lower,” downward,” and the like terms refer to the direction along mandrel 2 toward bottom sub 9. “Inner” and the like terms refer to the direction toward mandrel 2. “Outer” and the like terms reference the direction outwardly away from mandrel 2. The casing surface facing toward downhole tool 1 within the casing is conventionally referred to as the casing's “inner” face. These directional terms are for descriptive purposes only and do not limit the scope of the description. For example, the tool could be inverted within a casing and function in accordance with the instant-described principles.

FIG. 1 shows a first exemplary downhole tool 1. Arranged on mandrel 2 are top ring 3, upper slip 4 having upper slip buttons 5 (shown here are: 5 (5a.1-. 3, 5e.1-3)), upper cone 6, sealing element 7, lower cone 8, and bottom sub 9. Also arranged on mandrel 2 in FIG. 1 are lower slip 10 and lower slip inserts 11 (shown here: 11a.1 & 2, 11b.1, 11e.1 & 2). Upper slip 4, buttons 5, and cone 6 are collectively upper slip assembly 29. Lower slip 10, inserts 11, and lower cone 8 are collectively lower slip assembly 31. Downhole tool 1 is set at a chosen location within a casing. Setting downhole tool 1 comprises compressing top ring 3 and bottom sub 9 toward each other along mandrel 2. This compression moves upper slip 4 downward upon the inclined slope of upper cone 6, forcing upper slip 4 and slip buttons 5 radially outward against the inner face of the casing to penetrate and engage the casing and moves lower slip 10 upward upon the inclined slope of lower cone 8, forcing lower slip 10 and teeth 12 radially outward against the inner face of the casing to penetrate and engage the casing. The engaged upper slip buttons 5 and lower slip inserts 11 permanently or temporarily hold downhole tool 1 to the casing.

FIG. 2 shows a perspective view of an embodiment of insert 11. Insert 11 has teeth 12, serially identified as 12a-g. Tooth 12a is the back tooth. The slip's teeth 12 are on the outer face of tooth shelf 16. Back tooth 12a has back tooth notch 14. Insert base 18 is attached to and extends below tooth shelf 16 toward mandrel 2. Insert base 18 is comprised of base supports 17a-d. FIG. 2 shows base right channels 19a-c between base supports 18a-d. In an alternative embodiment, insert base 18 lacks channels or base supports.

FIG. 3 shows a different perspective view of insert 11. FIGS. 2 and 3 show that insert base 18 has greater radial length or depth toward mandrel 2 at its back end, i.e., the end below back tooth 12a, than at its front end, i.e., the end below tooth 12g. When the inserts are inserted in lower slip 10, the slope of insert base 18's lower surface 28 generally matches the inclined outer surface slope of lower cone 8. The angles of these matching inclined surfaces can be varied in accordance with the needs of the particular downhole tool and downhole task.

FIG. 4 shows a side cross-section view of insert 11 and teeth 12a-g. Insert 11 has back tooth face 20, back shelf 22, base back face 24, base bottom face 26, base bottom incline 28, base forward face 30, and base forward shelf 32. Preferably, base back face 24 and base forward face 30 are generally perpendicular to the mandrel 2's axis. This structure and orientation facilitate efficiency in manufacturing and placing inserts 11 within tooth pockets 54. It facilitates the alignment of insert 11 with the direct radial compression line of force between the interface of insert base 28 and cone 34 and the interface of teeth 12 and the casing. This structure promotes functional efficiency in setting and holding teeth within the slips and holding downhole tool 1 within the casing. In an embodiment, either or both base back face 24 and base forward face 30 may be acutely or obliquely angled relative to mandrel 2. In an embodiment, forward face 30 may be angled toward the upper end of cone 34, and base back face 24 angled inversely. In an embodiment in which insert 11 does not have a tooth shelf 16, the insert may be installed within the slip from within the slip.

FIG. 5 shows insert 11 viewed from its back face 18. Back tooth notch 14 is shown at the top and front center of back tooth 12a. Tooth shelf 16 is shown on base support 17a. In an embodiment, the structure between teeth 12 on the outside of the insert and the base bottom incline face 28 on the bottom of the insert does not need to be as shown in FIGS. 4 and 5 for the insert to function beneficially as described. Insert base 18 may have different configurations, subject to the set downhole tool's inserts being capable of becoming engaged with the casing and directly supported by the insert's base bottom incline face 28 against the cone. As non-limiting examples, insert base 18 may have sides that slope from an upper end where they support the teeth down to lower base bottom inclined face 28. The slope may be a smooth slope, accomplished with stairstep reductions in the base's width or the like, limitation being that the teeth are wider than base bottom incline face 28. Likewise, the functions of base back face 24 and base front face 30 may be accomplished with structures that support wider teeth 12 with a narrower base bottom incline face 28 directly on the cone.

Likewise, teeth 11's function of engaging the casing may be accomplished with engaging structures other than the teeth shown in FIG. 4. The casing engaging function may be performed with any structure on the outside of insert 11 capable of sufficiently engaging the casing to hold the downhole tool against the casing while the downhole tool's function at that casing location is undertaken. The engaging structure may be pointed, ribbed, or other structures of various sizes and shapes, wide wicker-like teeth, or other structures capable of engaging casing and holding the downhole tool to the casing.

FIG. 6 shows an embodiment of insert 11 from underneath insert 11. Base bottom faces 15a-d of base supports 17a-d are shown. FIG. 6 shows right base channels 19a-c and left base channels 21a-c between base supports 17a-d. Tooth shelf lower surface 44 is shown. FIG. 6A shows a view of insert 11's base right channels 19a-c and base left channels 21a-c, interfacing with right pocket ridges 62a-c and left pocket ridges 63a-c. Preferably, ridges 62 and 63 and channels 19 and 21 will tightly interface with each other for each insert 11. The outer slip body surface to inner slip body surface depth of slip pocket 49 and insert 11's base length provide a slip body 34/insert 11 interface, which is longer than the slip body 34/insert 11 interface of many similar conventional slip assembly's slips having slip pockets which do not fully extend through the slip from the slip's outer surface to the cone. Insert base channels 17 and 19 on the sides of insert base 16 correspond with and interlock with ridges 62 and 63 on the sides of the slip body 34. Slip pocket 34's right pocket ridges 62a-c correspond with and interlock with insert 11's right base channels 19a-c. Slip pocket 34's left pocket ridges 63a-c correspond with and interlock with insert 11's left base channels 21a-c. The greater surface area between insert 11 and slip body 34 than for many similar conventional slip assemblies provides more than the typical conventional slip body/insert surface area for holding an insert within a slip. The more in-depth interlocking geometry of the corresponding slip body ridges 62 and 63, and insert 11 channels combine to provide more than typical conventional geometric interlocking resistance for holding an insert within a slip body.

In an embodiment, ridges 62 and 63 and channels 19 and 21 are radial relative to mandrel 2. In alternative embodiments, ridges 62 and 63 and channels 19 and 21 may be angled to best hold the insert against the axial force against the downhole tool for which the slip assembly is holding the downhole tool within the casing. The lateral extent, width, and angles of ridges 62 and 63 and the depth, width, and angles of channels 19 and 21 may be varied. Some shapes, sizes, materials, and geometries will best hold insert 11 in slip body 34 against axial force on the downhole tool. Exemplary alternative embodiments comprise other insert base/slip pocket reciprocally interfacing shapes, curves, ribs, and holes to help hold the insert within the slip pocket. In embodiments where the slip is molded about the insert base, the insert base may have protrusions, inclusions, holes, and other discontinuities that interface with reciprocal slip surfaces to help hold insert 11 within slip body 34. An alternative insert embodiment is without channels, base supports, or ridges.

FIG. 7 shows an axial view of lower slip 10 from the lower end of mandrel 2. Lower slip 10 has slip segments 46a-e and slip waists 48a-e. Smaller slip waists 48a-e connect larger slip segments 46a-e. In operation, setting downhole tool 1 forces lower slip 10 over lower cone 8, which movement radially expands the slip; the radial expansion breaks lower slip body 34 at slip waists 48a-e, releasing slip segments 46a-e from each other as they further radially expand outward as further setting of the downhole tool further moves the slip up the cone's incline and radially out toward the casing. Lower slip body 34's inner facing incline 50 is shown.

FIG. 7A shows a side view of lower slip body 34. Slip segments 46a, 46b, and 46e are shown. Slip waists 48a and 48e are shown.

FIG. 8 shows a cross-sectional view of slip body 34. Slip waist 48a connects slip segments 46a and 46b. Slip pockets 49a and 49b, with their outer slip pockets 52a and 52b and connecting inner slip pockets 54a and 54b, are shown. Outer slip pocket 52a connects through inner slip pocket 49a in slip body 34 to slip body inner face 55a. Outer slip pocket 52b connects through inner slip pocket 49b in slip body 34 to slip body inner face 55b. Outer slip pocket 52a has an insert slot 53a defined by shoulder 56a and wall 57a. Outer slip pocket 52b has an insert slot 53b defined by shoulder 56b and wall 57b. Other slip pockets are similarly shaped, arranged, and numbered. The several outer slip pockets and inserts are located, sized, and shaped to enable outer slip pockets 52a-e to closely accept corresponding tooth shelves 16a-e of inserts 11a-e. Each inner slip pocket 54 has a right pocket ridge 62 and a left pocket ridge 63. Inner slip pockets 54a and 54b, right pocket ridges 62a.1 and 62b.1, and left pocket ridges 62a.2 and 62b.2 are shown. Slip body inner face 55, including slip upper incline 58 and slip lower incline 60, are shown. When the downhole tool is set, slip body inner face 55 is compressed against and moves over cone 8 to radially expand lower slip 10 outward from the cone and toward the casing.

FIG. 9 shows section A-A of FIG. 7's slip body 34. Slip pocket 49, slip outer pocket 52, slip waist 48, slip inner pockets 54, and slip fingers 64 are shown.

FIG. 10 shows section B-B of FIG. 7's slip body 34. Slip pockets 49, slip waists 48, slip shelf 56, slip waist 48, slip inner pockets 54, and slip fingers 64 are shown.

FIG. 11 shows an upper perspective view of slip body 34. Slip pockets 49, outer slip pockets 52a, inner slip pockets 54, slip waist 48d, outer slip shelves 56, slip lower incline 60, slip waists 48, and slip fingers 64 are shown. Outer slip pocket 52a has an insert slot 53a defined by shoulder 56a and wall 57a. Outer slip pocket 52b has an insert slot 53b defined by shoulder 56b and wall 57b.

FIG. 12 shows a lower perspective view of slip body 34. Outer slip pockets 52a and inner slip pockets 54, slip waist 48d-c are shown.

FIG. 13 shows a perspective view of lower cone 66. FIG. 13 shows cone upper base 68, ring gaps 70a and b, cone incline 72, guidance grooves 74a-c, and cone top 76.

FIG. 14 shows a side cutaway view of lower cone 66. Cone incline 72, cone upper base 68, guidance groove 74, and ring gaps 70a and b are shown.

FIG. 15 shows a top-down view of lower cone 66. Cone incline 72, guidance grooves 74a-e, and cone lower face 76 are shown.

FIG. 16 shows a view of cone upper base 68 from above lower cone 66. Ring gaps 70a-c with alternating coin base solid sections and gaps are shown.

FIGS. 17-24 show another slip assembly embodiment. Element numbers for elements of FIGS. 17-24, which are consistent with the elements of FIGS. 1-16, are maintained in FIGS. 17-24. Element numbers for elements of FIGS. 17-24, which are functionally the same but structurally not identical to the elements of FIGS. 1-16, are maintained on FIGS. 17-24 but with a different identifying subscript. For simplicity, base bottom face 26 of FIG. 17 retains the same number. However, cone grooves 74f-k of FIG. 24 have the same function but are not identical to cone grooves 74a-e of FIG. 13. Accordingly, FIG. 24 cone grooves 74 have different subscripts.

FIG. 17 shows a perspective view of an insert embodiment, namely insert 11a. Where FIG. 17's elements are identical to those of the elements of FIG. 4, FIG. 17's elements are numbered consistently with those of FIG. 4. The inserts of FIGS. 4 and 17 are, however, different. FIG. 4's straight base front face 30 is in FIG. 17 instead curved base front face 30a. FIG. 4's straight base bottom inclined face 28 is in FIG. 17 instead curved base bottom incline face 28a. FIG. 4's straight base back face 24 is in FIG. 17 instead curved base back face 24a. FIG. 4's insert base 18 has base channels 19 and 21. FIG. 17's insert base 18 does not have base channels 19 and 21; instead, insert base side 18a is flat. The transition between curved base front face 30a and flat first insert base side 18a begins at forward base transition line 30b. The transition between curved base bottom incline face 28a and flat insert base side 18a begins at lower base transition line 28b. The transition between curved base back face 24a and flat insert base side 18a begins at rear transition line 24b. The transition between curved base front shelf forward face 32a, and straight tooth shelf first side 16a is at forward tooth shelf transition line 32b. The transition between curved back tooth face 20 and straight tooth shelf first side 16a is at back tooth shelf transition line 20b. Likewise, in FIG. 19, bottom transition line 28c illustrates where curved base bottom incline face 28a, having curved downward from first insert base side 18a, reaches its furthest downward extent and begins curving upward toward first insert base side 18a. Transition lines 20b, 28c, 24b, 28b, 30b, and 32b are illustrative explanatory lines in this disclosure's figures. These transition lines are not marked on insert 11 and are not present as physical lines.

Insert 11's curved and round surfaces better distribute load into and about insert 11 relative to an insert with corners, which are stress concentrators. In the embodiment of FIGS. 4 and 17, the round shapes of curved base front shelf forward face 32a and curved base front face 30a distribute the downhole tool's downward axial thrust upon insert 11 in lower slip 10 over the insert's upward full radially shaped end, in contrast to an alternative insert with 90° corners. In other embodiments, curves other than a round curve between the insert's first and second sides are practicable. Back tooth face 20 and back face 24a are similarly round or curved.

FIG. 18 shows a top-down view of insert 11. Its elements are numbered consistently with FIG. 2. FIG. 19 is a view from underneath insert 11. Its elements are numbered consistently with FIG. 2. FIG. 20 is a side view of slip body 34. It is numbered consistently with FIG. 7A, with different element number subscripts where applicable. FIG. 21 is an axial view of cone 34. Its elements are numbered consistently with FIG. 7, with different element number subscripts where applicable. FIG. 22 is a cross-sectional view of cone 34. Its elements are numbered consistently with FIG. 7, with different element number subscripts where applicable. FIG. 22's slip inner pockets 50f-i functionally correspond with FIGS. 8-12 elements 50a-e. FIG. 23 shows a perspective view of lower cone 66. It is numbered consistently with FIG. 13, with different element number subscripts where applicable. FIG. 21 is an axial view of cone 34. FIG. 24 shows a top-down view of lower cone 66. It is numbered consistently with FIG. 15 with different element number subscripts where applicable.

Slip inserts 11 are inserted in each slip pocket 49. Tooth shelf 16 is held within outer slip pockets 52 and helps hold insert 11 within slip body 34. The depth of insert base 16 within slip body 34 from slip body 34's outer surface to slip pocket 34's inner surface against cone 8 is relatively longer than the depth of inserts in otherwise similar conventional inserts and slip assemblies for similarly sized downhole tools. The described embodiment's longer pocket 49/insert 11 interface depth helps hold insert 11 within slip body 34. During and after setting, the lower surface of insert base 16 is compressed directly against the hard surface of cone 8. Compressing incompressible hard insert 11 directly against the incompressible hard surface of cone 8 during and after setting creates a compressive force at the casing/insert 11 interface and at the insert 11/cone 8 interface, which helps hold insert 11 in place within slip body 34 and between the casing and cone 8.

Each of the slip 34 and insert 11 elements individually and collectively helps hold insert 11 within slip body 34 during and after setting more securely than many conventional inserts are held within many conventional slips during and after setting.

Slip inserts may be wickers, buttons, or other structures, for which the inner end is capable of being held in the slip and the outer end of which has one or more projections capable of engaging the inner wall of a casing. Inserts may be made from degradable or non-degradable, composite, or non-composite, metallic or non-metallic materials. In an embodiment, insert 11 is made of a hard material, such as ceramic, cast iron, titanium, carbide, a cement or mineral, glass, or other hard metallic or nonmetallic materials. In an embodiment, a usable ceramic is yttria-stabilized zirconia. In an embodiment, the insert's outer gripping members may be formed on the outer end of the insert by kurling, machining end and/or molding the insert substrate. In an embodiment, the insert's gripping elements and base me molded or formed as a single unit. The gripping members may be hardened to improve their engagement with the casing by using a flame sprayed carbide process on them. A ceramic insert may be advantageously more easily manufactured into desired shapes, less expensive, and easier to drill up into small pieces that do not interfere with subsequent downhole operations after the downhole tool is set and its operations completed than an insert that is otherwise similar but made of cast iron, titanium, or carbide. Inserts, particularly wicker-style inserts, may be radiused to match the curvature of the expected casing ID. In an embodiment, inserts shaped as shown in FIGS. 25-28 or inserts with other nonuniform geometries are preferably ceramic. Making such inserts from cast iron or other hard metals would be much more expensive. Drilling up such inserts made of cast iron or other hard metals into small pieces that do not interfere with subsequent downhole operations is more difficult than drilling up otherwise similar inserts, but made of ceramic.

Slip body 34 is preferably, but not necessarily, made of a different and softer material than insert 11. Slip body 34 is preferably, but not necessarily, comprised of a polymer with glass fibers, molded plastic, laminated composite, etc. Cone 8 is made of a rigid, incompressible material. The material can be either composite or non-composite, and it can be molded or not molded. Insert 11 and cone 8 are essentially incompressible relative to the slip pad. The cone is also significantly thicker and stronger than the slip pad. In an embodiment, insert 11 is positioned entirely through slip body 34 and directly against cone 8. Setting downhole tool 1 within the casing forces the bottom of insert 11 directly against cone 8 and forces the teeth of insert 11 directly against the casing. Compressing incompressible insert 11 between incompressible cone 8 and incompressible casing directly transmits the outward setting forces created by the slip moving up the cone to the insert's teeth, into the casing. This structure of these relatively incompressible elements and compression of the relatively incompressible elements against each other efficiently directly transmits the downhole tool's axial slip sliding over cone setting force into a radially outward insert teeth into the casing setting force. It also creates a direct, relatively incompressible geometric and physical cone/insert/casing impediment to unwanted movement of tool 1 within the casing during the downhole tool's setting and operation. The setting tool's vertically downward compressive force along the axis of the downhole tool's mandrel 2 is thus efficiently and directly converted into a radially outward force that pushes insert 11 and its teeth 12 into the inner wall of the casing.

Tooth shelf 16 held within slip outer pocket 51 provides additional shoulder 56 and wall 57 surface areas for holding insert 11 to slip body 34. Further, wall 57 provides another axial geometric block against tooth shelf 16, moving axially responsive to the axial force on the set downhole tool against which the slip assembly holds the set downhole tool.

Setting downhole tool 1 within the casing forces the slip assemblies out against the casing. Teeth 12 are the outermost portion of the slip assembly to engage the casing. Forcing teeth 12 into the casing compresses teeth 12 inward toward mandrel 2. This compresses tooth shelf 16 inward against slip body 34. Tooth shelf 16 compressing slip body 34 compresses slip body 34's base material within ridges 62 and 63 against insert base 18 and against and within channels 19 and 21. Thus, setting the downhole tool pushes teeth 12 radially inward, pushing tooth shelf 16 radially inward, pushing slip body 34 radially inward, which both makes the compressed slip body 34 material more rigid about insert 11 and compresses slip body 34 axially against insert 11. Accordingly, tooth shelf 16 makes the set downhole tool's slip assembly's inserts 11 more resistant to insert 11 being axially forced from the slip assembly.

In an embodiment, the described slip assembly holds the downhole tool to the casing by compressing at least one insert directly between the cone and the casing so the outer end of the insert is directly compressed against and engages the inner face of the casing to hold downhole tool 1 against the casing and the inner end of the insert is directly compressed against the outer face of the cone and is slidable up the slope of the outer face of the cone when downhole tool 1 is being set. Because the insert is more incompressible than the slip, this structure more directly translates the vertical setting force of the setting tool into horizontal setting force against the casing than a similar slip assembly in which a similar insert does not fully extend from the teeth outside the slip body to the cone. It is believed this geometry provides some benefit during plug setting and use, direct axial compression of the inserts between the cone and casing as shown, causing the inserts to radially press outward into a better engagement with the casing. Setting tool 1 in the casing with the disclosed slip and insert combination provides greater resistance to unwanted movement of tool 1 within the casing than comparable downhole tools with a structure similar to the described tool, except lacking the described slip assembly's slip body 34's and insert 11's described structure.

Preferably, slip pockets 49 and ridges 62 and 63 are uniformly shaped and configured, and inserts 11 and channels 19 and 21 are uniformly shaped and configured so that inserts 11 can be randomly inserted into any slip pockets 49. This facilitates efficiency in manufacturing and assembling the components. Alternatively, some slip pockets 49 and their ridges 62 and 63 and some inserts 11 and their channels 19 and 21 may be shaped and configured differently, so a first configuration slip pocket 49 and insert 11 fit with each other, and a second configuration slip pocket 49 and insert 11 fit with each other, etc. Slip pockets 49 and inserts 11 may have different depths. Slip pockets 49 and inserts 11 located toward the upper end of slip body 34 may have a shorter depth and length than slip pockets 49 and inserts located toward the lower end of slip body 34. Alternatively, a design choice for some slip assemblies may be for some or all slip pockets 49 not to open at the slip inner surface facing cone 8, such shorter slip pockets 49 holding correspondingly shorter inserts 11. This may facilitate manufacturing and assembly efficiencies.

The disclosed embodiments teach similar embodiments having more or fewer, longer or shorter, wider, or narrower structures than the described elements. For example, there may be multiple inserts with multiple teeth or buttons of different compositions, sizes, widths, shapes, etc. The insert bases may have many sizes, shapes, angles, and base supports. Base supports, channels, slip pockets, and ridges may vary in number, size, shape, etc. The teachings for a lower slip apply to an upper slip.

In an alternative embodiment, one or more slip pockets 49 have ridges 62 and 63, and one or more inserts 11 have channels 19 and 21; the ridges and channels are shaped and configured so a first configuration slip pocket 49 and insert 11 fit with each other, and a second configuration slip pocket 49 and insert 11 fit with each other, etc. Slip pockets 49 and inserts 11 may have varied sizes, shapes, and depths. Slip pockets 49 and inserts 11 located toward the upper end of slip body 34 may have a shorter depth and length than slip pockets 49 and inserts located toward the lower end of slip body 34. In an embodiment, at least some of the multiple inserts have a channel located in the insert's base and extending into the insert, and at least some of the slip pocket ridges correspond with at least some of the insert base channels, and at least some inserts with a channel are located in at least some slip pockets with a ridge, and at least some of the inserts' channels closely correspond with the inserts' respective slip pockets' ridge. In an embodiment, the slip assembly is configured so that when the downhole tool is being set within the casing, the inserts with channels that fit within slip pockets having corresponding and matching ridges are more securely held within the slip pockets and are less likely to be forced from their slip pockets when the downhole tool is being set than similar inserts which do not have channels and are not fit within slip pockets having corresponding and matching ridges. In an embodiment, at least some slip pockets have multiple ridges located within the slip pocket, along the slip pocket's longitudinal axis, and extending into the slip pocket; at least some of the multiple inserts have multiple channels located in the insert's base, along the insert's base's longitudinal axis and extending into the insert. At least some of the slip pocket ridges correspond with at least some of the insert base channels, and at least some inserts with channels are in at least some slip pockets with ridges. At least some of the inserts' channels closely correspond with the slip pockets' ridges. In an embodiment, at least some ridges are oriented radially relative to mandrel 2, and at least some channels are oriented radially relative to mandrel 2. In an embodiment, at least some slip pockets have multiple ridges on one side of the pocket and multiple ridges on the other side of the pocket. At least some inserts have multiple channels on one side of the insert base and multiple channels on the other side of the insert base, and the slip pocket has multiple ridges, and the insert's multiple channels are located, shaped, and sized. Hence, the ridges and channels correspond, and at least some inserts with multiple channels on one side of the insert base and multiple channels on the other side of the insert base are capable of being closely held within at least some of the pockets with multiple ridges on one side of the pocket and multiple ridges on the other side of the pocket.

In an alternative embodiment, some, or all, slip pockets 49 do not open at the slip's inner surface where it faces cone 8, such shorter slip pockets 49 holding correspondingly shorter inserts 11. Insert base 18 of shorter insert 11 has a sufficient depth to hold insert 11 within the slip during setting and operations. In an alternative embodiment, the slip assembly is arranged so that the bottom of the insert is close to the bottom of the slip base but does not fully reach through the bottom of the slip base. In this embodiment, a thick or thin portion of the slip base, preferably ⅛ inch or within the range of 1/16-¼ inch, is at the bottom of the slip base pocket between the bottom of the insert and the cone. Alternatively, the slip assembly may be arranged so there is a vacant space between the base bottom face 26 and the bottom of the slip base pocket. One or more of these alternative embodiments may facilitate manufacturing and assembly efficiencies.

Insert 11 may be press-fitted within slip pockets 49 or affixed to the slip body 34, with adhesives or both. Alternatively, slip body 34 may be injection molded, compression molded, or pour molded about the several inserts 11. In addition to manufacturing efficiencies, molding permits different insert base 18 and slip pocket 49 geometries. An insert 11 within a molded slip body 34 may be designed with one or more flanges extending perpendicularly or at an angle from insert base 18. Such flanges provide more insert base/slip body surface area and a geometric block against insert base 18 being pulled out of slip body 34 by axial or radial forces on teeth 12 during and after setting downhole tool 1. In an embodiment, an insert with base channels 19 and 21 and slip base ridges 62 and 63 may have deeper and thinner channels, and longer and thinner ridges permitted by molding may provide more surface area and more geometric blocking of axial force on insert 11. Thinner channels and ridges permitted by molding enable the inclusion of more channels and ridges than permitted by inserting and gluing inserts 11 into slip body 34.

FIGS. 25-28 show various insert base enablements with insert base 18a-d beneath tooth shelf 16a-d. FIG. 25 shows cavities 25a and 25b within insert base 18a. A molded material or glue within cavities 25a and 25b will have more surface area and provide more mechanical and geometric blocking to hold insert base 18a within slip 4 than a similar base but without cavities. FIG. 26 shows cavities 27a and 27b within insert base 18b. A molded material or glue within cavities 27a and 27b will have more surface area and more mechanical and geometric blocking to hold insert base 18a or 18b within slip 4 than a similar base but without cavities. Insert base 18d of FIG. 28 has a thinner upper base 112, a thicker lower base 114, and a base shelf 116. A molded material or glue about base 18d with its thinner upper base 112 provides a slip material area between tooth shelf 16 and thicker lower base 31, and its base shelf 116 has more surface area and provides more mechanical and geometric blocking to hold insert base 18d within slip 4 against being pulled out of slip 4 than a similar base 18 of FIG. 4, which lacks thinner upper base 112 and base shelf 116. Embodiments shown in FIGS. 25-28 provide different surface areas, voids, and geometries for molding or gluing insert 11 within slip 4.

FIGS. 29 and 30 show an alternative embodiment of downhole tool 1. About mandrel 102 is top ring 103, upper slip 104, upper cone 106, sealing element 107, lower cone 108, and bottom sub 109. Upper slip 104 has one insert per slip segment, i.e., slip segment 105a has insert 112a, upper slip segment 105b has one slip segment 112b, etc. Lower slip 100 has slip segments 146a, 146b, etc., each slip segment having two inserts. In an embodiment, slip segment 146a has two slip segments, 111a and 111b. The slip segments are connected to each other about the mandrel 102 via slip waists, for example, 148a. In this embodiment, the described cone groove/slip finger anti-twist/anti-rotation structure and function, and other embodiments herein are provided by lug 177a held tightly within and protruding from cone orifice 179a. Guidance lug 177a fits between slip segments 146a and 146b. When downhole tool 1 is being set, slip segments 146a and 146b move over cone 108. Guidance lug 177a separates slip segment 146a from slip segment 146b at the immediately adjacent slip waist 148a as lower slip 100 is expanded over cone 108. Once lower slip 100 is expanded over cone 108 and lug 177a is forced between slip segments 146a and 146b, guidance lug 177a obstructs the rotational movement of lower slip 100 about cone 108. Because the rotational movement of the slip is a cause of stress on inserts that may cause the inserts to be pulled or rolled out of a slip, guidance lug 177a functions to help keep inserts 111a and 111b from being forced from lower slip 100. The functional effect of this structure and arrangement is to cause downhole tool 101 to be held more securely within the casing after downhole tool 101 is set within the casing than similar downhole tools without such guidance lugs. Similar guidance lugs are located within the downhole tool's upper and lower cones to deter rotation of the downhole tool's upper and lower slips and thus more securely hold downhole tool 101 within the casing. The guidance lugs are comprised of a hard material selected for its ability to withstand rotational forces while preventing slips from rotating during downhole tool setting or operations.

Button and insert rolling may occur on a tool's X and/or Y axis or both axes during tool setting and use. Downhole tools with the disclosed guidance fins, guidance lugs, and notches will have slips that rotate about the downhole tool less and have inserts and buttons that are twisted out of the slip in the tool's X and/or Y axis or both axes less than similar downhole tools, but without the disclosed guidance fins, guidance lugs, and notches. Inserts in downhole tools have an outer end that extends outside the slip for engaging the casing and have an inner end that directly abuts the cone. Such inserts are less likely to be twisted out of the slip in the tool's X and/or Y axis or both axes than similar inserts in similar downhole tools, but which similar inserts do not directly abut the cone. Downhole tools with the disclosed guidance fins, guidance lugs, and notches and with inserts, buttons, or other projections that are axially longer than circumferentially wide will have slips that rotate about the downhole tool less and have inserts and buttons that are twisted out of the slip in the tool's X and/or Y axis or both axes less than similar downhole tools, but without the disclosed guidance fins, guidance lugs, and notches.

The several differences between the described embodiment and many conventional slip assemblies advantageously combine to better keep slip 10's inserts 11 from sliding, flipping out, or damaging the casing while setting the downhole tool 1, more directly transmitting the setting tool's downward vertical force into outward a radial force of the insert teeth against the casing and better hold the tool to the casing than similar conventional slip assemblies that do not use the described slip assembly structures. In an embodiment, the inserts do not extend fully through the slip body, and the insert body is perpendicular to the angle of the cone's sloped outer surface. Conventional downhole tool structures may be substituted for some but not others of these described structures. In an embodiment, the insert may extend fully through the slip to the cone but not have teeth wider than the insert or vice versa.

FIGS. 31-33 show an insert embodiment, namely insert 181. FIG. 31 shows first groove 183 on first base side 185 of base 186. Base bottom incline face 187 has outer edge bevel 189. First groove 183 opens to back base face 191 and does not open to front base face 192.

FIG. 32 shows first groove 183 on first base face 185 and second groove 193 on second base face 195. FIG. 33 is a side view of insert 181 showing first groove 183 on first base face 185. The apparent discontinuity between first groove 183's back end 197 and back base face 191 in FIG. 33 is perceptual only due to the curvature of back face 191 shown in FIG. 31.

In an embodiment, during the manufacture of a slip assembly, a slip is molded about insert 181, injection or compression molded. Insert 181 is a hard material, in an embodiment, ceramic or iron. The slip comprises a weaker and more compressible material, in an embodiment, thermoplastic or other flowable material useful for being molded into a slip about insert 181. The slip material flows into grooves 183 and 193, or about the described first and second protrusions, during the molding process. Molding slip material about insert 181 and into grooves 183 and 193 may more reliably completely fill grooves 183 and 193 or about the described first and second protrusions with slip mold material than a similar process with similar slip mold material would fill insert base hole cavities that extend completely through the insert base as shown in FIGS. 25 and 26 or other cavities that extend completely through the insert base. In another embodiment, the insert has at least a first protrusion on an axial side of the insert base which first protrusion is at least 0.002 inches high and extends at least 40% of the axial length of the base; and a second similar protrusion on the other axial side of the insert base; the slip body is molded about the insert; and the insert is at least partially held within the slip body by slip body material molded about the first protrusion and second protrusion. In an embodiment, the molding process uses a three-piece mold, a first mold on top of the insert, a second mold beneath the insert on the smaller base end, and a third mold on the wide end of the base. This arrangement permits the first mold to be removed, and the third mold removed, which then allows the molded insert to be removed from the second mold. Thereafter, the slip or slip pads may be over molded upon the insert. An insert with radial grooves, such as shown in FIGS. 2 and 3, may be similarly molded, using a bottom mold and a top mold, and then similarly over molded.

Slip material molded into insert base grooves 183 and 193 or about the described first and second protrusions will adhesively, mechanically, and geometrically help hold insert 181 within the slip while setting the tool within the casing and while using the tool in fracing or other downhole operations. In an embodiment, slips with slip material molded into insert base grooves 183 and 193 or about the described first and second protrusions are held within the slip without gluing the inserts into slip pockets after the slip has been manufactured. Inserts with slip material molded into insert base grooves 183 and 193 or about the described first and second protrusions are less likely to be pulled or twisted out of the slip during setting, fracing, or other downhole operations than similar inserts but without insert base grooves 183 and 193 or about the described first and second protrusions and thus without slip material molded into insert base grooves 183 and 193 or about the described first and second protrusions.

An insert with grooves 183 and 193, or about the described first and second protrusions, is less likely to break during setting or downhole operations than similar inserts with insert base hole cavities that extend completely through the insert base. An insert with grooves 183 and 193 or the described first and second protrusions is less likely to be pulled or rolled out of the slip during setting or downhole operations than similar inserts, but without grooves 183 and 193 or the described first and second protrusions. An insert with grooves 183 and 193 or about the described first and second protrusions is less likely to break during setting or downhole operations than similar inserts with insert base hole cavities that extend completely through the insert base, as shown in FIGS. 25 and 26. An insert with grooves 183 and 193 or the described first and second protrusions is less likely to break during setting or downhole operations than similar inserts with insert base 18d of FIG. 28, which has a thinner upper base.

For inserts glued into a machined slip, insert base grooves 183 and 193 or about the described first and second protrusions, to improve bonding between the inserts and the machined slip pads. If insert 181 with grooves 183 and 193 or about the described first and second protrusions is inserted into and glued into a machined slip, the attachment glue may more reliably completely fill grooves 183 and 193 than the glue would fill a similar insert, but with insert base hole cavities 25 and 27 that extend completely through the insert base. Inserts with glue or adhesive in insert base grooves 183 and 193 or about the described first and second protrusions are less likely to be pulled or twisted out of the slip during setting, fracking, or other downhole operations than similar inserts, but without insert base grooves 183 and 193 or about the described first and second protrusions and thus without glue or adhesive in insert base grooves.

Inserts in downhole tools are typically the hardest and strongest part of the downhole tool to penetrate and engage the casing and incompressibly hold the downhole tool to the casing during setting and fracing. Hard and strong inserts are more difficult to drill or mill out after the downhole tool's operations have been completed, and the downhole tool needs to be removed from the well than other downhole tool elements. Drilling, milling, or otherwise removing this disclosure's relatively much larger inserts, such as insert 11, can be even more difficult than for many conventional buttons and inserts. This disclosure's inserts 11 and 181 are longer, wider, and deeper than many conventional buttons or inserts. This makes drilling out this disclosure's inserts both more essential for enabling follow-on downhole operations and more difficult.

Insert base grooves 183 and 193 address this problem by facilitating more easily and quickly drilling out insert 181 relative to drilling out similar inserts, such as insert 11, but without insert base grooves 183 and 193. Particularly for ceramic inserts, insert base grooves 183 and 193 provide longitudinal drill-out and mill-out fracture propagation points/grooves along a substantial length of the otherwise hard-to-drill-out and hard-to-break-up relatively large insert base 186. Drilling out the disclosed longer, wider, and deeper inserts with insert base grooves 183 and 193 more quickly breaks the insert into pieces small enough to be circulated out and more quickly produces smaller drilled-out insert pieces than drilling out similar inserts, but without insert base grooves. Producing smaller drilled-out insert pieces speeds up circulating the pieces out of the well relative to producing large insert pieces and speeds up the process to the next operation stage. This is particularly true for ceramic inserts. Producing smaller pieces further lessens interference and obstruction with follow-on operations in the well. Similar radial grooves in the insert base may provide some similar advantages.

In an embodiment, the serial back-to-back tooth and valley configuration of the disclosed insert's casing-facing teeth 12a-g facilitates drilling out inserts 11 and 181 relative to drilling out similar inserts, but without the disclosed inserts' serial back-to-back tooth and valley teeth. Many conventional inserts with the disclosed inserts' length, width, and depth, but without serial back-to-back teeth and valleys, would be relatively harder to drill out. The disclosed insert's serial back-to-back valleys between the insert's several teeth provide drill-out fracture propagation points along a substantial length of the otherwise hard-to-drill-out and hard-to-break-up solid insert tooth shelf. Drilling out the disclosed inserts with their serial back-to-back tooth and valley teeth produces smaller drilled-out insert pieces than drilling out similar inserts, but without serial back-to-back tooth and valley teeth 12a-g. This is particularly true for ceramic inserts of equivalent size and shape, but without serial back-to-back tooth and valley teeth 12. Facilitating breaking the disclosed insert into insert pieces and obtaining smaller insert pieces in this way enables more quickly drilling out the insert and more quickly circulating the pieces out of the well more quickly relative to similar inserts, but without the disclosed serial back-to-back tooth and valley teeth.

The inner surface of many conventional slips is uniform and smooth. The outer surface of many conventional expansion cones is uniform and smooth. Many conventional downhole tools are set within the casing at a target downhole position by radially expanding the tool's slip against the casing. This is done by axially compressing the slip, with its uniform and smooth inner surface, axially over the tool's expansion cone's uniform and smooth inclined outer surface. This movement slides the inner surface of the slip axially and radially along the cone's inclined outer surface. The slip's uniform and smooth inner surface facilitates its sliding along the cone's uniform and smooth outer surface.

Setting a downhole tool in this conventional way puts a high compressive force on the interface between the cone's outer face and slip inner face. Sliding such a conventional slip over a conventional cone produces relatively uniform radial pressure along the slip's inner surface and the cone's outer surface. Nevertheless, the conventional matching uniform surfaces and uniform radial forces between the slip inner surface and cone outer surface enable a slip/cone axial sliding and a slip axial expansion process that does not cause the inner surface of the sliding slip to deform or dig into the cone. Many conventional slips have buttons or inserts for engaging the surrounding casing that do not extend from the outer end of the button or insert fully through the slip to the cone. Rather, many conventional buttons or inserts extend from the outer surface of the slip only partly into the slip. Such buttons or inserts do not extend fully through the slip to the cone's outer surface.

Although this disclosure's embodiments provide certain benefits, they present design issues. This disclosure's inserts 11 and 181 differ from many conventional inserts or buttons by extending radially from the insert's outer casing-engaging teeth fully through the slip to the slip's inner surface. Because of this structure, the insert's base 18 or 187 directly engages the outer surface of the tool's expansion cone 8.

Insert teeth 12 extend outside the outer surface of lower slip body 34, and insert 11 or 181 fully extend through the slip to the slip's inner surface. Setting downhole tool 1 by compressing slip body 34 axially and radially along the cone's inclined outer surface pushes the insert's base bottom incline face 28 or 187 inward past the slip's inner face and into the outer surface of cone 8. Conventional buttons and inserts in conventional slips do not push inward past the slip's interface and into the outer surface of cone 8.

FIG. 4 shows front insert edge 35 where base front face 30 and base 33 meet. Many conventional expansion cones are more compressible than hard inserts 11 and 181. Pushing hard insert edge 35 inward beyond the uniform and smooth inner surface of the slip body 34 pushes insert edge 35 into the cone's outer surface. This produces a potential for the front insert edge to extend beyond the inner surface of the slip body and into the cone surface. Because of this, during the setting of the downhole tool, rather than a smooth and uniform inner surface of the slip body and the base of the insert sliding along the uniform and smooth surface of the cone, instead front insert edge 35 may dig into the cone surface. Many conventional slip bodies or pads are more compressible than hard inserts 11 at 181. The insert is relatively incompressible. Inserts 11 and 181 comprise hard, strong materials, often ceramic materials.

Once front insert edge 35 begins digging into the cone surface during setting, rather than insert 11 and the slip sliding along the cone's outer inclined surface, front insert edge 35 may progressively gouge into or dig into the cone as the setting progresses. Insert edge 35 digging into the outer surface of the cone may have adverse consequences. Deforming the cone in this way detracts from uniformly and predictably forcing inserts against the casing.

The extent of each of the several inserts with a front insert edge 35 digging into the cone and its effect is relatively unpredictable compared to a slip with a uniform, smooth inner surface sliding along the cone's outer surface. This makes the radial holding force of an insert 11 whose front insert edge 35 is gouged into the cone against the casing less and less predictable than for a similar insert that did not gouge into the cone. Further, because this condition and its effect may affect each of the slip's several inserts, each of which may also be digging into the cone, the collection of the several inserts' forces holding the tool to the casing is likewise less and less predictable than for a similar collection of short conventional buttons or similar inserts in a similar slip which conventional buttons or inserts do not dig into the cone. Inserts that have dug into the cone are more likely to be twisted or forced out of their slip pockets than similar inserts that do not dig into the cone. A greater axial force may be required during setting to push inserts that extend fully through the slip and dig into the cone than is required to slide a similar insert smoothly along the outer surface of the cone.

FIG. 31 shows an embodiment having outer edge bevel 189 on insert 181. Bevel 189 tapers, slopes, or curves at the juncture of the lower end of base front face 30 and front base bottom inclined face 187. Bevel 189's attack angle relative to the cone's incline outer surface protects the relatively softer composite cone against being deformed by hard front insert edge 35 because it enables the insert to slide up the cone's inclined face during setting. Bevel 189's attack angle relative to the cone's inclined outer surface lessens the likelihood of insert 181 digging into the cone while setting downhole tool 1 relative to how much a similar insert, which lacks outer edge bevel 189. Bevel 189 facilitates insertion of the insert into its slip pocket by narrowing the bottom face of the insert relative to a similar but not beveled bottom face of insert 11.

In an embodiment, the outer edge of base bottom face 24 is beveled, a chamfer with an angle of about 20° to 45° relative to the mandrel before the downhole tool is set. This facilitates fitting the insert into the slip insert pocket during tool assembly. In an embodiment, the junction of base bottom inclined face 187 and base front face 192 is a rounded smooth curve or fillet. This rounded corner helps the insert more likely to slide along the outer surface of the cone without digging into the cone or digging as deeply into the cone relative to how the junction of base bottom inclined face 187 and base front face 192 being a 90° corner would slide along the outer surface of the cone or dig into the cone. The junction of base bottom inclined face 187 and base front face 192 being a smooth curve or fillet, prevents or lessens the degree to which the insert digs into the outer surface of the cone during downhole tool setting relative to the junction being a 90° corner. An insert that slides along the outer surface of the cone requires less axial power to move along the cone than an insert that digs into the outer surface of the cone and more dependably transmits radial thrust through the insert between the cone and the casing.

FIGS. 34 and 35 show an embodiment of downhole tool 200. Downhole tool 200 is similar in some respects to downhole tool 1. In an embodiment, lower slip body 202 is pre-segmented, meaning its four slip pads (slip pads 204, 206, and 208 are shown; the fourth is symmetrically behind downhole tool 200 in FIG. 35) are manufactured separately as individual pads. In another embodiment, the lower slip body is a single molded unit with its individual slip pads connected to each other with linkages located and configured to separate between the slip pads when the tool is set in the slip pads. In an embodiment, the slip pads are arranged about the mandrel 2, as shown, to comprise a slip assembly. The several slip pads are held together as slip body 202 on downhole tool 200 with slip rings (conventional, not shown) within slip ring grooves 210 and 212 in ways known in the art. When downhole tool 200 is set within the casing, axial compression together of bottom sub 218 and lower cone 222 radially expands slip 202. This radial expansion breaks the slip rings, which frees each slip pad from the other slip pads, enabling it to individually expand outward and set the pad's inserts into the casing without being constrained by the other slip pads. Benefits of using the disclosed pre-segmented lower slips are increased manufacturing efficiency, less waste, greater placement accuracy during setting of the tool, more accurate deployment strength, and retention of more slip pad strength.

In the embodiment of FIGS. 34 and 35, lower slip body 202 has four slip pads. In an embodiment, lower inserts 214a-d are held within lower slip body 202 in one of the structures described in this disclosure. In the embodiment of FIGS. 34 and 35, each slip pad has two inserts. In other embodiments, slip pads may have one, two, three, four, or five inserts. Other embodiments may have a combination of inserts, buttons, or wickers.

Potential impediments to securing the tool to the casing are the slip pads not cleanly separating between each other to provide desired equidistant and symmetrical placement of the inserts about the tool and into the casing and the inserts being pulled or rotated out of their slip pockets due to rotational movement of the slip pads about the tool during setting or downhole operations. In the embodiment of FIGS. 34 and 35, bottom sub guidance fins 216 (216a and b are shown) are located on the upper end of bottom sub 218 and below lower slip body 202. Lower slip body 202 has lower slip lower notches 224 (224a and b are shown). Lower notch 224a is at the lower interface of slip pad 206 and slip pad 208. Lower notch 224b is at the lower interface of slip pad 206 and slip pad 204. Bottom sub guidance fin 216a is immediately adjacent to or inserted within lower notch 224a. Bottom sub guidance fin 216b is immediately adjacent to or within lower notch 224b.

Lower cone guidance fins 220 (220a and b are shown) are located on the lower end of lower cone 222 and above Lower slip body 202. Lower slip body 202 has lower slip upper notches 226 (226a and b are shown). Upper notch 226a is at the upper interface of slip 206 and slip 208. Upper notch 226b is at the upper interface of slip pad 206 and slip pad 204. Lower cone guidance fin 220a is immediately adjacent to or inserted within lower notch 224a. Lower cone guidance fin 220b is immediately adjacent to or inserted within lower notch 224b.

When the described downhole tool is set, the lower cone guidance fins and bottom sub guidance fins adjacent to or within the slip pad's upper and lower slip notches are forced axially toward each other. Axial compression of bottom sub 218 and lower cone 220 forces lower slip body 202 radially outward, which separates its slip pads from each other and toward the casing. The lower cone guidance fins and bottom sub guidance fins help force the lower slip pads to separate from each other.

In the embodiment of FIGS. 34 and 35, top ring guidance fins 228a and b are located on the upper end of upper cone 230 and below upper slip 232. Upper slip 232 has upper slip lower notches 234a and b. Lower notch 234a is at the lower interface of slip pad 236a and slip pad 236b. Lower notch 234b is at the lower interface of slip pad 236b and slip pad 236c. Top ring guidance fin 228a is immediately adjacent to or inserted within lower notch 234a. Upper cone guidance fin 228b is immediately adjacent to or within lower notch 234b.

Top ring guidance fins 238a and b are located on the lower end of top ring 240 and above upper slip 232. Upper slip 232 has upper slip upper notches 251a and b. Upper notch 251a is at the upper interface of slip 206 and slip 208. Upper notch 251b is at the upper interface of slip pad 236c and slip pad 236b. Top ring guidance fin 238a is immediately adjacent to or inserted within upper notch 251a. Top ring guidance fin 238b is immediately adjacent to or inserted within lower notch 251b.

When the tool is set, guidance fins adjacent to or within the upper and lower slip notches are forced axially toward each other. Axial compression of bottom sub 218 and lower cone 220 forces lower slip body 202 radially outward, which separates its slip pads from each other and toward the casing, and the guidance fins help force the slip pads to separate from each other. Likewise, axial compression of upper cone 230 and top ring 240 forces upper slip 232 radially outward, which separates its slip pads from each other and toward the casing, and the guidance fins help force the slip pads to separate from each other.

In an embodiment, the outer radius of bottom sub fins 216 and upper cone guidance fins 228 is the same as the outer radius of bottom sub 218 and top ring 240, respectively. Bottom sub fins 216 and upper cone guidance fins 228 extend away from bottom sub 218 and top ring 240, and sufficiently into the notches between the several slip pads to deter or prevent rotation of the slip pads about the mandrel during setting. In an embodiment, the outer radius of lower cone guidance fins 220 and upper cone guidance fins 228 is the same as the outer radius of the widest portion of lower cone 222 and upper cone 230, respectively. Lower cone guidance fins 220 and upper cone guidance fins 228 extend away from lower cone 222 and upper cone 230 and sufficiently into the notches between the several slip pads so the fins will deter or prevent rotation of the slip pads about the mandrel during setting. Setting will force the slip pads up the upper and lower cones' inclined slopes. The lower cone guidance fins 220 and upper cone guidance fins 228 are located on the cones and configured to extend radially from the cones' inclined slopes, so lower cone guidance fin edges 201a and b and upper cone guidance fin edges 228a and b extend radially, i.e., perpendicularly relative to the mandrel. Lower cone guidance fins 220 and upper cone guidance fins 228 are an integral part of the cones and extend axially and radially from the cones' inclined surfaces. Similar edges on the far side of the tool of FIG. 34 have similar dimensions and configurations. In an embodiment, top ring guidance fin edges 239a and b and upper top ring notches 251a and b are curved or shaped so the fin edges tightly fit within or interlock with the notches between the slip pads to separate the slip pads at slip waists 254 a and b and 256 a and b and to prevent or deter the slip pads from rotating about the tool.

Use of the disclosed upper and lower separate slip pads and upper and lower guidance fins is useful for controlling how the slip pads separate during setting, are expanded outward against the casing, and become located against the casing relative to each other, and helps prevent the slips and slip pads from rotating about the downhole tool during setting and downhole operations and from potentially rotationally pulling the inserts out of the slips.

People with ordinary skill in the art will appreciate that the described guidance fins and notches are similarly present about the downhole tool, although not shown in this disclosure's figures. Guidance fins and guidance lugs deter rotation of the downhole tool's upper and lower slips and thus more securely hold downhole tool 101 within the casing. Downhole tools with the disclosed guidance fins, guidance lugs, and notches will have slips that rotate about the downhole tool less and have inserts and buttons that are twisted out of the slip less than similar downhole tools, but without the disclosed guidance slips, guidance lugs, and notches. Guidance fins and guidance lugs are comprised of a hard material selected for its ability to withstand rotational forces while preventing slips from rotating during downhole tool setting or operations. The number of guidance fins, guidance lugs, and notches will vary as the number of slip pads varies. Guidance fins, guidance lugs, and notches may be particularly beneficial for downhole tools that use inserts, buttons, or other projections that are axially longer than circumferentially wide. Such axially long and circumferentially narrow inserts, buttons, or other projections may be more susceptible to being rotated or twisted out of their slip pockets if their slip or slip pad rotates about the downhole tool. Downhole tools with the disclosed guidance fins, guidance lugs and notches and with inserts, buttons, or other projections that are axially longer than circumferentially wide will have slips that rotate about the downhole tool less and have inserts and buttons that are twisted out of the slip less than similar downhole tools, but without the disclosed guidance slips and notches.

The lower slip assembly is comprised of lower slip body 202 and its inserts. Its inserts primarily hold the downhole tool within the casing against downward forces on the downhole tool. The upper slip assembly is comprised of upper slip 232 and its inserts. The upper slip assembly holds the downhole tool within the casing against upward forces on the downhole tool. The lower slip assembly must typically hold the downhole tool against stronger downward forces on the downhole tool than the upper slip assembly must hold the downhole tool to the casing against upward forces on the downhole tool. Fracing exerts tremendous downward forces on the downhole tool. In this embodiment, it is expedient to make the lower slip assembly capable of holding downhole tool 202 to the casing more securely than the upper slip assembly can hold downhole tool 202 to the casing. Making an upper slip assembly with the same expensive materials and structures as the lower slip assembly is uneconomic and unnecessary. In the embodiment of FIGS. 34 and 35, the lower slip assembly has more inserts to press against the casing than the upper slip assembly has inserts to press against the casing. In this embodiment, the lower slip assembly has twice as many inserts as the upper slip assembly. For reasons of economy or other reasons, an upper slip assembly may use buttons, wickers, or other retention devices rather than or in addition to the described relatively expensive inserts.

In the embodiment of FIGS. 34 and 35, the lower slip assembly is comprised and shaped to be more robust than the upper slip assembly and to hold its inserts to the casing more securely than the upper slip assembly holds its inserts to the casing. In an embodiment depicted in FIGS. 34 and 35, the upper slip is a single-piece injection-molded cylinder. The upper slip is more economically molded as a unitary cone with weaker material because it needs to withstand less pressure-induced force than the lower slip. The lower cone typically bears more casing/insert inward radial load than the upper cone. In an embodiment, the lower cone may be designed with more expensive, more rigid, and less drillable material, such as a filament wound composite, while the upper cone may be designed with a relatively less costly, less rigid, more drillable material, such as a compression molded material. In downhole tool 202, the lower slip assembly comprises stronger materials, more materials, and more inserts than the upper slip assembly. The lower slip comprises compression-molded separate slip pads. In other embodiments, either slip may be injection or compression molded, and either slip may comprise a single piece or individual pieces. The lower slip's compression-molded individual pads are stronger than the unitary up on per slip. The lower slip pads are assembled about the mandrel and held on the tool with upper and lower slip bands. The disclosed slip assemblies teach a person with ordinary skill in the art how to distribute the casing/insert load between the upper slip and upper cone, and between the lower slip and the lower cone, as may be desirable for the particular downhole task.

Molding or over-molding inserts, such as finished ceramic or metal inserts, in place within a slip or slip pad, both mechanically arrest the disclosed inserts within the slip or slip pad and provide better adhesion between the insert and the slip or slip pad. Molding inserts in place within slips or slip pads during the manufacture of the slips or slip pads provides manufacturing and tool assembly efficiency relative to inserting inserts within finished slips or slip pads.

Petal ring 250 provides an additional barrier to the unwanted flow of drilling fluid or other fluids between tool 200 and the casing after tool 200 is set in the casing. In addition to petal ring 250 being sized and shaped to restrict unwanted flow between tool 200 and the casing, the disclosed petal ring 250 will often accumulate frac sand and other wellbore material that drifts down through the drilling fluid or other fluid to the upper side of petal ring 250. The combination of petal ring 250 itself and frac sand on top of petal ring 250 together provides a better seal against fluid flow between tool 200 and the casing than a pristine petal ring 250. In this way, petal ring 250 provides an additional seal or a backup seal to sealing element 252, in this embodiment, a rubber seal. In the embodiment of FIGS. 34 and 35, petal ring 250 is injection or compression molded of the same nonmetallic material as upper slip 232. In this embodiment, it is unnecessary to make petal ring 250 from more expensive materials such as the materials of Lower slip body 202. In another embodiment, sealing ring 250 may be comprised of a malleable and degradable metallic material that is expanded outward against the casing during setting.

Petal ring 250 is separate from cone 222. During the setting of the downhole tool 1, a petal is hinged outward toward the casing, in which position it holds sealing element 7 or the rubber against being squeezed out of its position on downhole tool number 1. Petal ring 250 can also be used above the upper slip in a bridge plug application. As is desirable for different tasks, a downhole tool may have no petal rings, one petal ring, or a stack of two, three, four, or more petal rings, and the petal rings may be located either or both above the lower slip and the upper slip.

Expansion of the slip assembly during setting causes the inserts to engage and penetrate the casing. The outward radial force of the inserts against the casing, which causes the inserts to engage and penetrate the casing, is matched by an equal inward radial force on the inserts. In an embodiment, because the insert's base bottom inclined face 187 presses directly against the cone, a portion of each insert's inward radial casing/insert load is directly communicated through the insert to the cone. In an embodiment, because each insert's tooth shelf 44 presses against corresponding slip shoulder 56, a portion of each insert's inward radial casing/insert load is communicated from the insert's tooth shelf 44 to slip shoulder 56. Inward load communicated to slip shoulder 56 is dispersed through the slip and ultimately to the slip inner surface/cone outer surface interface. The slip inner surface/cone outer surface interface area is much larger than the insert base bottom inclined face 187/cone outer surface interface surface area. The more surface bearing area of the slip shoulder 56 that the tooth shelf 44 engages, the more inward radial casing/slip load the slip communicates to the slip inner surface/cone outer surface interface relative to the amount of inward radial casing base/insert load that the insert directly communicates to the insert base bottom inclined face 187/cone outer surface interface. The inward radial load that the slip bears is spread across the slip/cone surface more widely than the inward radial casing base/insert load is spread across the insert base bottom/cone surface. Portions of the slip or pad that are not directly beneath the tooth shelf are pushed against the casing during setting and transmit load between the cone and casing. In an embodiment, load is transmitted between the cone and the casing by each of multiple inserts which are pressed directly against both the casing on the cone, multiple slip or pad portions which are between the tooth shelf and the cone and inserts, and multiple slip or pad portions which pressed directly against both the casing and the cone.

The insert is sized and shaped to fit in the slip pocket. In some embodiments, as shown in FIGS. 1 and 35, the preset downhole tool is configured so that the outer edges of the teeth of inserts 11 and 215 extend outside the slip outer surface. In an embodiment, the outer edges of the teeth of the downhole tool as it is being run through the hole to where it will be set, extend outside of the outer side of the slip pad, or stand off from the slip pad, by about 0.055 to 0.065 inches. This permits the expanding teeth to engage and penetrate the casing before the expanding slip pad contacts the casing. In some embodiments, the outer edge of the teeth may be at, near, below, or slightly below the outer surface of the slip pad, and the tool is configured and the cone and insert are sized so that setting the tool expands the teeth out from the tool into engagement with the surrounding casing. Functional requirements that set structural limitations on positioning the teeth relative to the outer surface of the slip are that when the tool is being run into the hole the outer edge of the teeth not extend outward so far that they injure the casing or get hung up on the casing as the tool is being run through the casing to the tool's end point; and that when the tool is being set, the outer end of the teeth extend sufficiently outward from the outer surface of the slip pad to engage the casing and secure the tool to the casing. Smaller tools intended for use within smaller casings with a smaller tool-to-casing distance may have a smaller extension of the teeth from the outer surface of the slip. Larger tools designed for use within large casings with larger tool-to-casing distances may have a larger extension of the teeth from the outer surface of the slip.

In an embodiment, the outer edge of the teeth is at or below the outer surface of the slip and the bottom edge of the insert extends inward from the inner surface of the slip pad and toward the cone, so compressing the slip against the cone during setting pushes the bottom edge of the insert up and deploys the teeth outside the outer surface of the slip pad. In another embodiment, the teeth are recessed within the slip, the outer edge of the teeth being less than 0.03 inches below the outer surface of the slip pad. In another embodiment, the outer edge of the teeth is at the outer surface of the slip. In another embodiment, the outer edge of the teeth is within 0.1 inches above or below the outer surface of the slip. In another embodiment, the outer edge of the teeth is within 0.2 inches above or below the outer surface of the slip.

Some embodiments comprise making the tooth shelf wider or narrower to increase or decrease the amount of inward radial casing/insert load that the slip directly communicates via its insert base bottom inclined face 187 to the cone relative to the amount of inward radial casing/insert load that, via tooth shelf 44/shoulder 56 communicates through to the slip/cone surface. Some embodiments comprise an insert without a tooth shelf. Such embodiments utilize the inserts to transfer more load directly via the inserts between the cone and the casing than inserts with a tooth shelf, which transfers some of the load through the slip pad to the cone. Making the insert deeper or less deep relative to the depth of the slip, making the insert teeth extend further or less far outside the slip, and making the bottom of the insert base wider or narrower, making the tooth shelf 44/shoulder interface wider or narrower will increase or decrease the amount of inward radial casing base/insert load that the insert directly communicates to a point on the cone.

In an embodiment, the depth of the insert base, FIG. 4 base 18 or FIG. 31 second base 186, is sufficiently longer than shown in FIGS. 4 and 81 that the insert base extends through the inner surface of its retaining slip or pad and into groove 74 of FIG. 13 or 23. Upon downhole tool 1 being set, axial movement of the setting assembly upward along lower cone 66's inclined surface pushes the lower setting assembly's insert base bottom inclined faces 28 or 187 axially and radially along groove 74 and further into grooves 74. In an embodiment, base 18 and second base 186 are curved with a radius that matches the radius of the corresponding curved groove 74, so base 18 and second base 186 closely interface with groove 74. Setting downhole tool 1 powerfully thrusts the several insert bases further into their corresponding grooves 74 and transmits the downhole tool's setting pressure on the inserts within the cone groove 74s. During setting downhole tool 1 the extended insert bases extend sufficiently far within the cone's several grooves 74 and are held within grooves 74 with sufficient pressure that the inserts within grooves 74 prevent or deter slip or pad rotation about the cone. This arrangement holds each insert within its pad against being rotated, pushed, or twisted out of its slip pocket. Such extended insert bases within cone grooves may replace some or all of the slip fingers 64.

In an embodiment, the manufacture of the slips may begin by winding filaments about a circular hollow cage. The radial wound circular filaments are then placed in a circular mold, and polymer material is added to the mold, producing a molded circular cage with radial wound filaments. In some embodiments, the fiber may be a carbon fiber reinforced polymer which is infused with a polymer resin, such as epoxy, that is then cured, usually with heat and pressure, to solidify the composite material and bond the fibers together. Molded material is then removed from the molded circular cage to leave axial channels between slip pads, the slip pads connected by webs extending between slip pads.

In an embodiment, FIG. 36 shows first slip pad 260 and second slip pad 262 separated by axial channel 264. Most of the radial filaments wound about the circular slip cage containing first and second slip pads 260 and 262 were cut when the material of axial channel 264 was removed from between first slip pad 260 and second slip pad 262, but leaving webs between and connecting the slip pads. After removal of the material to create axial channel 264, first slip pad 260 and second slip pad 262 are separated by first, second, third and fourth separation spaces 266, 268, 270 and 272, respectively, and remain connected by first, second and third web, 274, 276 and 278, respectively. The first web has first, second, and third holes 280, 282, and 284, respectively. The second web has second web first hole second hole, and third hole, 286, 288, and 290, respectively. The third web has third web first hole, second hole, and third hole 292, 294, and 296, respectively. First pad stability notch 298 and second pad stability notch 300 are shown. Reciprocal lugs on the top ring, facing the upper side of the upper slip pads, and on the bottom sub, facing the lower side of the lower slip pads, fit within 298 and 300. The lugs within the stability notches stabilize the slip pads and deter rotation of the slip pads about the downhole tool while the downhole tool is being run to its destination and while the downhole tool is being set. In an embodiment, the length of the lugs and the depth of the stability notches is less than 0.3 inches.

The webs have holes which are located axially relative to each other, so few or no of the filaments that were originally wound radially about the slip cage now pass radially through the webs. The described structure produces first slip pad 260 and second slip pad 262 which are strong enough to serve as slip pads in a downhole tool, yet, because the tension of the radial filaments has been released due to the filaments through them having been cut at the slip pad edges, the pads can be more easily drilled out when the downhole tool's function has been completed than if the wound filaments were continuously wound throughout the slip pad cage. The webs are strong enough to hold the slip pads together about the tool while the tool is being run in, and are weak enough to break and permit first slip pad 260 and second slip pad 262 to separate when the tool is set in the casing. The weakness of the webs decreases the likelihood of the pads significantly deforming or rotating during setting because the webs will break before they cause such pad deformation. A factor in these structures and functions is that the web holes interrupt the filaments running through the webs. Without the holes, some radial filaments would continue through the circular slip cage and hold the slips together more strongly than is desirable. Varying the number of webs between pads, the size and width of the webs, the size, shape, and placement of the web holes relative to the other web holes, and the number and characteristics of the filaments will produce different functional results. In an embodiment, the holes in the webs are sized and located relative to each other and relative to the size and composition of the webs to permit enough filaments to remain between the slip pads to provide the circular slip cage with enough strength to hold the pads together while the tool is run in and beginning to be set and to also prevent so many filaments to remain between the slip pads that the slip pads are held together too strongly and will detrimentally deform or rotate during setting. In an embodiment, the holes have a radius of between 0.05 and 0.06. In an embodiment, the holes have a radius of between 0.03 and 0.08.

In an embodiment where the cone comprises a less expensive material than the slip, it may be desirable to design the slip assembly so the cone bears more inward radial load directly through the inserts direct force on the cone relative to the cone receiving the setting tool's inward radial load across the larger slip/cone interface. The insert base bottom inclined face 187/cone outer surface interface is narrower than the slip inward surface/cone outer surface interface. More inward load communicated through the inserts on relatively narrow outer cone surface areas may require increasing the cone's stiffness, durability, and thickness to maintain its integrity. This may require more expensive cone material, but will also enable the use of slip material that is less stiff, durable, and thick, and thus less costly. In an embodiment where the cone comprises a more expensive material than the slip material, it may be desirable to design the slip assembly so that more of the inward radial load is communicated through the slip/cone interface. This may be done by increasing the size of the tooth shelf lower face, increasing the slip's stiffness, durability, thickness, etc.

The design of the tool's elements, their parameters, materials, shape, and the like may be materially adjusted by persons with ordinary skill in the art in anticipation of the wellbore, operating conditions, casing, expected upward and downward force on the tool, the anticipated duration of the tool is to hold within the casing, the diameter of the casing, cost of materials, cost of manufacturing, ease of use and other conditions and constraints. In various embodiments, the insert may be longer or shorter; the tooth shelf may be wider or narrower and thinner or thicker; the insert base may be more or less deep and thinner or thicker; the insert base incline may be shallower or steeper, the teeth wider or narrower, the teeth taller or shorter, the teeth fewer or more, the teeth angles shallower or steeper, the slip material stiffer and stronger or more malleable and weaker, the slip thinner or thicker and stiffer and stronger, the cone thinner or thicker and stiffer and stronger, the slip/cone incline interface steeper or shallower, etc. Slip assembly dimensions will vary substantially depending on the design of the downhole tool, the number of slips, the size of the downhole tool, the inner diameter of the casing, and other variables.

Slip assembly dimensions will vary substantially depending on the design of the downhole tool, the number of slips, the size of the downhole tool, the inner diameter of the casing, and other variables. In an embodiment for a slip for a downhole tool for a 51/2 inch casing as shown in FIGS. 7-12, the sealing assembly has six slip segments 46a-f arranged about mandrel 2 and cone, the slip segments each connected by slip waists 48a-f. In other embodiments, the number of slip segments may be three to nine. In an embodiment, slip 10 is 2.5 inches long. In other embodiments, slip 10 may be 1.5 to 4 inches long. In other embodiments, slips may be up to 7 inches long. In an embodiment, the matching cone incline 72 and facing lower slip face is about 17° relative to the mandrel 2. In another embodiment, the matching cone incline 72 and facing lower slip face may be 12° to 25° relative to mandrel 2.

In an embodiment of a FIG. 1 tool 1 for a 51/2 casing, the insert may be about 1.3 to 1.5 inches in total length from one end of the tooth shelf 16 to the other end and about 0.5 to 1.1 inches in total depth, including teeth 12, tooth shelf 16, and base bottom face 26. In an embodiment, insert base 18 may be about 0.2 to 0.3 inches wide, about 1.0 to 1.4 inches long, and about 0.5 to 0.7 inches deep. In an embodiment, the insert may be two to four times axially longer than the insert teeth are wide. In an embodiment, the insert may be 5% to 25% axially longer than the insert base is long. In an embodiment, the insert teeth may be two to three times wider than the insert base. In an embodiment, the insert may be two to three times axially longer than the insert is wide. In an embodiment, the base incline may be about 15° to 19° to match the cone's similar incline. In an embodiment, a FIG. 1 style insert 11 may have 5 to 9 teeth, the width of teeth 12 may be about 0.3 to 0.5 inches, and teeth 12 may be about 0.1 to 0.3 inches high. The up-hole side of the teeth may have in about 10° to 30° angle relative to the mandrel, and the downhole side of the teeth may be at an about 110° to 130° angle relative to the mandrel. These angles will be reversed for downhole tool 1's upper slip 4. In an embodiment, a FIG. 1 style tooth shelf 16 may have about 0.05 to 0.3 inch depth and about 0.3 to 0.6 inch width from one side of the tooth shelf to the other. Back tooth notch 14 may have an about 110° to 130° angle relative to the mandrel. In an embodiment, the tooth shelf lower surface extends equidistantly from about 0.1 to 0.4 inches past insert base 18 on each side and end of insert base 18. In an embodiment, the tooth shelf lower surface extends about 0.1 to 0.4 inches past each side of insert base 18 on each side and extends about 0.1 to 0.4 inches past each end of insert base 18. In an embodiment for a FIGS. 6 and 6A style insert 11 with three insert channels on each side, i.e., 19 a-c and 21 a-c, the distance between the channel troughs may be about 0.2 to 0.4 inches.

In an embodiment with a FIG. 17 style insert 11 for a 51/2 inch downhole tool, insert 11 is about 1.3 to 1.5 inches long from a first end of the tooth shelf 16 to the second end of tooth shelf 16 and is about 1.0 to 1.4 inches long from a first end of insert base 18 to the second end of insert base 18. In an embodiment, insert 11 may be 0.8 to 3.0 inches long from the first end of tooth shelf 16 to the second end of tooth shelf 16. In an embodiment, the insert may be 1.0 to 2.8 inches long from the first end of insert base 18 to the second end of insert base 18. In an embodiment, insert 11 may be 0.3 to 0.6 inches wide from a first side of tooth shelf 16 to a second side of tooth shelf 16 and 0.2 to 0.4 inches wide from a first side of insert base 18 to a second side of insert base 18. In an embodiment, insert 11 may be within the range of 0.2 to 0.8 inches wide from a first side of tooth shelf 16 to a second side of tooth shelf 16 and within the range of 0.1 to 0.5 inches wide from a first side of insert base 18 to a second side of insert base 18. In an embodiment, insert 11 has 5 to 7 teeth 12a-g.

In an embodiment, insert 11 may have 3 to 12 teeth. In an embodiment, teeth 12a-g have an up hole face angle of about 15° to 25° relative to mandrel 2 and a downhole face angle of about 80° to 100° relative to the mandrel. In an embodiment, teeth 12a-g may have an up hole face of about 10-30° and have a downhole face angle of about 70-120° angle. In an embodiment, teeth 12a-g are about 0.3 to 0.5 inches in width and extend about 0.2 to 0.4 inches above tooth shelf 16. In an embodiment, teeth 12a-g may be within the range of 0.2 to 0.5 inches in width and extend 0.15 to 3.5 inches above tooth shelf 16. In an embodiment, tooth shelf 16 has a depth of about 0.5 to 1.5 inches. In an embodiment, tooth shelf 16 may have a depth of about 0.05-0.5 inch. In an embodiment, the depth of teeth 12a-g and tooth shelf 16 is about 0.1 to 2.4 inches. In an embodiment, the depth of teeth 12a-g and tooth shelf 16 is about 0.1 to 0.3 inches. In an embodiment, the height of teeth 12a-g above tooth shelf 16 is about 0.3 to 1.0 inches. In an embodiment, the height of teeth 12a-g above tooth shelf 16 is about 0.1 to 1.5 inches. In an embodiment, the distance between the crests of teeth 12a-g is about 0.1 to 0.4 inches. In an embodiment, the distance between the crests of teeth 12a-g is about 0.1 to 0.8 inches. In an embodiment, for lower slip 10, the upper surface of the up hole edge of insert 11 is at approximately the same outer surface level as the outer surface of the lower slip 10 pad holding insert 11. In an embodiment, for lower slip 10, the outer surface of the up hole edge of insert 11 is about 0.05 to 0.1 inches below the outer surface of the lower slip 10 pad holding insert 11. These teachings apply to the upper slip and upper inserts, often with the directions reversed.

In an embodiment, the disclosed insert may have more than three times more anchoring surface area than a traditional button insert having a circumference equal to the width of the teeth of the disclosed insert. In an embodiment, the disclosed insert may have more than twice as much anchoring surface area than a traditional button insert having a circumference equal to the width of the teeth of the disclosed insert. In an embodiment, the disclosed insert may have more than 50% more anchoring surface area than a traditional button insert having a circumference equal to the width of the teeth of the disclosed insert.

In an embodiment, the disclosed slip and insert combination has no metal content. In an embodiment, the slip is comprised of composite without any metal and the insert is comprised of ceramic without any metal and the disclosed downhole tool within the disclosed slip may be drilled out of the casing twice as fast as a similar downhole tool, but the similar downhole tool has cast-iron slips and metallic buttons. In an embodiment, the slip is comprised of composite without any metal and the insert is comprised of ceramic without any metal and the disclosed downhole tool within the disclosed slip may be drilled out of the casing 50% faster than a similar downhole tool, but the similar downhole tool has cast-iron slips and metallic buttons.

In an embodiment, outer slip pocket 52 is sized slightly larger than tooth shelf 16, and slip inner pocket 54 is sized slightly larger than insert base 18. In an embodiment, insert 11 will be held within the pockets with glue, epoxy, or other adhesive, and the pockets sized to accept insert 11 together with an appropriate amount of adhesive. In an embodiment, the insert is attached to the slip via a press fit, and outer slip pocket 52 and slip inner pocket 54 are sized closely to that of the insert. In an embodiment, the pad is over-molded about the insert, and the outer dimensions of the insert and the inner dimensions of the slip pockets are essentially the same.

In an embodiment, lower cone 66 has four to six grooves 74, and the slip has matching slip fingers. In an embodiment, lower cone 66 may have three to nine cone grooves 74 and matching slip fingers. The distance between the grooves/fingers will vary in accordance with the number of grooves/fingers, the size of the downhole tool, the size of the cone, etc. In an embodiment, the reciprocal grooves and fingers are about 0.10. to 0.3 inches in depth. In an embodiment, the reciprocal grooves and fingers are about 0.05 to 0.6 inches in depth. In an embodiment, the cone has at least first and second grooves and each extends at least one half the length of the cone, and each has a portion which has a depth of at least 1/16 of an inch, and the slip has at least first and second fingers and each extends at least 25% of the length of the finger's slip and each first and second finger has a finger portion which has a depth of at least 1/16 of an inch. In another embodiment, the first and second grooves have a portion which has a depth of at least ⅛ of an inch, and the first and second fingers each has a portion which has a depth of at least ⅛ of an inch.

In an embodiment of a downhole tool as shown in FIGS. 31-35, designed for use in a 5½ inch casing, second base 186 is about 1.0 to 1.4 inches long, first groove 183 and second groove 193 are each about 0.7 to 2 inches long, about 0.2 to 0.4 inches wide and about 0.05 to 0.2 inches deep.

In an embodiment, the insert's radial length is equal to or longer than the insert's axial length. This structure provides greater resistance to rotational twisting out of the insert than a similar insert, but which similar insert has an axial length greater than its radial length. In an embodiment, the insert has a solid or hollow “V” or curved shape, the point of the “V” or the upper end of the curve being toward the wider end of the cone, and the insert's teeth are aligned axially relative to the mandrel. This structure also provides greater resistance to rotational twisting out of the insert than a similar insert, but which similar insert has an axial length greater than its radial length.

These illustrative measurements and dimensions are intended to assist a person of ordinary skill in the art, having the benefit of this disclosure, to design various inserts and slip assemblies. These measurements and descriptions do not limit the scope of the disclosure or the scope of the claims. Persons of ordinary skill in the art will appreciate that this disclosure's measurements and dimensions for downhole tools for use in, for example, 51/2 inch casing, will be adjusted for downhole tools of different sizes for use in various size and type casings. This disclosure's dimensions and elements may also be adjusted for different slip assemblies within the scope of this application's teaching to a person of ordinary skill in the art.

In an embodiment, for a 5½ inch, 17-23 weight lbs./ft casing, an exemplary plug's specifications are 4.3 inch outside diameter, 1 inch inside diameter, 16 inch length, 2.125 ball size, Baker #20, GO 3 5-8 inches, 250° F. temperature rating, and a 10,000 psi pressure rating. Illustrative examples of how dimensions are adjusted for different-sized downhole tools intended for use in differently sized casings are provided in the table below.

Insert Length to Width Ranges

Casing

length range (inches)

Width range (inches)

	size	Short	Tall	Narrow	Wide

	7″	0.92	3.79	0.29	1.21
	6″	0.76	3.17	0.24	1.00
	5½″	0.70	2.81	0.22	0.90
	5″	0.63	2.56	0.19	0.82
	4½″	0.57	2.36	0.18	0.75
	4″	0.51	2.02	0.16	0.67
	3½″	0.46	1.93	0.14	0.59

A person with ordinary skill in the art of designing downhole tools, having the benefit of this disclosure, may use this chart and other design variables to adjust measurements stated in this disclosure to create downhole tools appropriate for various casing sizes, downhole conditions, and tasks.

The present description is adapted to attain the ends and advantages mentioned and those inherent therein. The embodiments disclosed above are illustrative only, as the present description may be modified and practiced in different but equivalent manners apparent to those skilled in the art, benefiting from the teachings herein. No limitations are intended to limit the details of construction or design shown other than as described in the claims. The illustrative embodiments disclosed above may be altered or modified; all such variations are considered within the scope and spirit of the present description.

The terminology used herein only describes various implementations and is not intended to be limiting. The singular forms “a,” “an,” and “the” are intended to include the plural forms as well unless the context indicates otherwise. The terms “comprises” and “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and groups, therefore. Compositions and methods described in terms of “comprising,” “containing,” or “including” various components or steps can also “consist essentially” of or “consist of the various components and steps.

Disclosed numerical values have the meaning they would have to a person of ordinary skill in the art at the time of the disclosure. Persons with ordinary skill in the art, given the benefit of the present disclosure, will appreciate that other embodiments may have different dimensions, uniformly scaled or not, that perform the described functions. Numerical values and proportions may vary to the extent that various embodiments meet the functional requirements described herein. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. Every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a to b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. If there is any conflict in the usage of a word or term in this specification and one or more patents or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

The corresponding structure, materials, acts, and equivalents of all means or steps, plus functional elements in the claims below, are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description is presented for illustration and description, but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The implementations were chosen and described to explain the principles of the disclosure and the practical application and to enable others of ordinary skill in the art to understand the disclosure for various implementations with various modifications suited to the particular use contemplated. Those skilled in the art will readily recognize that various additions, deletions, modifications, and substitutions may be made to these implementations. Thus, the scope of the protected subject matter should be judged based on the following claims, which may capture one or more concepts of one or more implementations.

Although the description has been described regarding a specific embodiment, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodiments will become apparent to those skilled in the art upon reference to the description of the description. It is, therefore, contemplated that the appended claims will cover such modifications, alternatives, and equivalents that fall within the true spirit and scope of the description.

For the avoidance of doubt, U.S. provisional patent applications Ser. Nos. 63/658,737, 63/708,340, and 67/763,031 are fully incorporated by reference herein, the same as if they were physically restated in this application in their entirety, and priority is claimed to them.

The present description is adapted to attain the ends and advantages mentioned and those inherent therein. The embodiments disclosed above are illustrative only, as the present description may be modified and practiced in different but equivalent manners apparent to those skilled in the art, benefiting from the teachings herein. No limitations are intended to limit the details of construction or design shown other than as described in the claims. The illustrative embodiments disclosed above may be altered or modified; all such variations are considered within the scope and spirit of the present description.

The terminology used herein only describes particular implementations and is not intended to be limiting. The singular forms “a,” “an,” and “the” are intended to include the plural forms as well unless the context indicates otherwise. The terms “comprises” and “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and groups, therefore. Compositions and methods described in terms of “comprising,” “containing,” or “including” various components or steps can also “consist essentially” of or “consist of the various components and steps.

Disclosed numerical values have the meaning they would have to a person of ordinary skill in the art at the time of the disclosure. Persons with ordinary skill in the art, given the benefit of the present disclosure, will appreciate that other embodiments may have different dimensions, uniformly scaled or not, that perform the described functions. Numerical values and proportions may vary to the extent that various embodiments meet the functional requirements described herein. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. Every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a to b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. If there is any conflict in the usage of a word or term in this specification and one or more patents or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

The corresponding structure, materials, acts, and equivalents of all means or steps, plus function elements in the claims below, are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description is presented for illustration and description, but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The implementations were chosen and described to explain the principles of the disclosure and the practical application and to enable others of ordinary skill in the art to understand the disclosure for various implementations with various modifications suited to the particular use contemplated. Those skilled in the art will readily recognize that various additions, deletions, modifications, and substitutions may be made to these implementations. Thus, the scope of the protected subject matter should be judged based on the following claims, which may capture one or more concepts of one or more implementations.

Although the description has been described regarding a specific embodiment, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodiments will become apparent to those skilled in the art upon reference to the description of the description. It is, therefore, contemplated that the appended claims will cover such modifications, alternatives, and equivalents that fall within the true spirit and scope of the description.