SYSTEM FOR ANCHORING A DOWNHOLE TOOL TO A CASING WITH AN EXPANDABLE SPIRAL THREADED SLIP DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. Section 120 from U.S. patent application Ser. No. 18/525,304, filed on 30 Nov. 2023, entitled “EXPANDABLE SPIRAL THREADED APPARATUS AND METHOD FOR ANCHORING A DOWNHOLE TOOL TO A CASING, AND METHOD FOR ASSEMBLING THE APPARATUS”.

See also Application Data Sheet.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

Not applicable.

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to isolating zones in a wellbore. More particularly, the present invention relates an anchoring component of a downhole tool to a casing. The downhole tool, such as a plug or packer, isolates a zone in the wellbore. Even more particularly, the present invention relates to an expandable spiral threaded anchoring component in a system for anchoring the tool to the casing.

2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98

A slip is a basic anchoring component to hold a downhole tool 1 at a desired location in the borehole, as shown in FIGS. 1-5. The basic anchoring component includes a slip 2 and cone 3. The cone 3 is pushed into the slip 2, which fractures while expanding radially outward to contact the casing 4 or tubing in the borehole. The textured outer surface of the slip 2 grips the casing 4 to prevent movement. FIG. 2 shows the basic anchoring component in the context of a downhole tool 1. FIG. 2 shows a conventional plug or packer with two slips 2, indicating that the downhole tool 1 has two anchoring components. With two slips 2, one in each direction, the downhole tool 1 resists movement within the casing 4 in both directions. Characteristics of an anchoring component, including slip geometry, ramp style, ramp geometry, and tooth style, are known to affect the properties of the anchoring component. The angled surfaces on slips and cones work using the principles of an inclined plane. The anchoring component functions as a force amplifier due to the mechanical advantage provided by the ramps. An applied axial force (input force) is converted to a larger radial force (output force). The high output force allows the slip to expand and bite into the casing or tubing.

A barrel slip 8 is a particular type of slip of an anchoring component that resists movement in both directions, as shown in FIG. 3. The geometry, ramp style, ramp geometry, and tooth style can also be modified for a barrel slip 8. Instead of needing a complementary slip for resisting movement in each direction along the casing, a barrel slip 8 can hold the downhole tool in both directions. FIGS. 3-5 show a prior art barrel anchoring component 5 of a downhole tool. The barrel anchoring component 5 comprises the barrel slip 8, a first straight threaded cone 6, a second straight threaded cone 7, and a mandrel 9. The sectional views of FIGS. 4-5 show multiple inclined surfaces interacting between the barrel slip 8 and the first straight threaded cone 6 and between the barrel slip 8 and the second straight threaded cone 7. FIG. 4 shows the run-in configuration with the smaller diameter of the component 5 and the threads of the barrel slip 8 friction fit between respective threads of the straight threaded cones 6, 7. FIG. 5 shows the expanded configuration with the larger diameter of the component 5 and the threads of the barrel slip 8 pushed outward along the incline angle of the threads of the straight threaded cones 6, 7. In the larger diameter of FIG. 5, the component 5 engages the casing or tubing within the borehole for locking the downhole tool in place. Like stacked cones, instead of a single conical surface, the barrel slip 8, the first straight threaded cone 6, and the second straight threaded cone 7 are in ratchet engagement. Force is used to push the first straight threaded cone 6 in one direction along the mandrel 9 and to push the second straight threaded cone 7 in an opposite direction along the mandrel 9 so that the first straight threaded cone 6 and the second straight threaded cone 7 are closer together. The multiple inclined surfaces of the threaded surfaces pushing against each other expand the barrel slip 8 to set the downhole tool in the casing or tubing.

There are various patents and patent publications disclosing anchoring components of a downhole tool, including barrel slips.

U.S. Pat. No. 5,944,102, issued on 31 Aug. 1999 to Kilgore et al, U.S. Pat. No. 5,906,240, issued on 25 May 1999 to Kilgore et al, U.S. Pat. No. 6,378,606, issued on 30 Apr. 2002 to Swor et al, and U.S. Pat. No. 6,481,497, issued on 19 Nov. 2002 to Swor et al, all disclose the prior art straight threaded barrel slip with ratchet engagement to opposing straight threaded cones. The various locking features or shear points of this barrel slip are connectors that still break apart as the barrel slip expands. The assembling and disassembling both require the snap-fit engagement that risks damage and deformation to the tight tolerances between the multiple inclined surfaces of the ramps and threads.

U.S. Pat. No. 11,441,371, issued on 13 Sep. 2022 to Fripp et al, and US Publication No. 2017/0145780, published on 25 May 2017 for Castro et al, disclose barrel slips with different components, such as sleeves and rings, for expansion, instead of cones.

One problem with the current barrel slip is the assembling and dissembling of the barrel anchoring component. The convention assembling method requires a press to install the barrel slip onto the straight threaded cones. Furthermore, the barrel slip is at least partially expanded over the threaded cone ramps during assembly using the press. Thus, there is a risk of permanently deforming the barrel slip or damaging the barrel slip during the assembling with the press. Additionally, for disassembling from the expanded configuration, the current barrel slip is almost impossible to release from the casing or tubing for disassembling without destroying the barrel slip. If one cone is not installed correctly, the current barrel slip cannot be removed without damaging the current barrel slip itself. The assembling is difficult because the ratchet engagement between the barrel slip and the threaded cones is a force-fit relationship. The barrel slip or the cones are deformed or at least distended to even assemble the tool, so there is weakening during assembly.

Another problem with the current barrel slip is precision tolerance. The ramp and slope engagements of the multiple inclined surfaces on both the barrel slip and each of the threaded cones must be very close in order to hold the expanded position of the barrel slip. The current barrel slip is very difficult to machine due to the extremely tight tolerance requirement. Tight tolerancing of linear dimensions is necessary to ensure proper timing and engagement of the inclined surfaces of the barrel slip and threaded cones. That is, the corresponding ramp pairs need to all contact as close to the same time as possible to ensure that the load is evenly distributed around each thread of the cone and each respective ramp of the barrel slip. The barrel slip is easily unbalanced with chips and gaps between the inclined surfaces of the current barrel slip and threaded cones. In practice, this level of precision machining leads to high manufacturing costs and very high scrap rates due to deviations. It also is a burden to quality control and engineering groups to address and disposition non-conforming parts.

As a result of the ratchet engagement with tight tolerance of the current barrel slip, the load capacity of the anchoring component is limited. The distribution of the load in use is defined by the contact area between the barrel slip and threaded cones. In the straight threaded cones, the contact area remains constant around the mandrel.

There are also various patents and patent publications disclosing spiral threaded surfaces, instead of straight threaded surfaces. The prior art spiral threads are on various components of the downhole tool, although not on the anchoring component of the downhole tool. U.S. Pat. No. 8,002,045, issued on 23 Aug. 2011 to Ezell et al, shows another downhole tool with threaded surfaces for expanding slips. The ratchet or coaxial threads are disclosed as interchangeable with spiral or helical threads. U.S. Pat. No. 4,494,777, issued on 22 Jan. 1985 to Duret, describes spiral threaded pipe joints between tubular members in a drill string. US Publication No. 2019/0234177, published on 1 Aug. 2019 for Silva et al, shows other spiral or angular threaded surfaces in a downhole tool. The consequences of spiral threads for assembling and disassembling and the consequences of increased force needed to separate spiral threaded surfaces are known in the prior art.

Variations on the placement and orientation of spiral threads on different components of a downhole tool are also known. Chinese Patent No. CN109973043, published on 5 Jul. 2019 for Guo, Dajin et al, and U.S. Pat. No. 3,472,520, issued on 14 Oct. 1969 to Burns, disclose spiral threads in different orientations and on different components, not the anchoring components of the downhole tool. Ratchet engagement of straight threaded surfaces on non-anchoring components of the downhole tool are disclosed in U.S. Pat. No. 3,584,684, issued on 15 Jun. 1971 to Anderson et al, U.S. Pat. No. 4,156,460, issued on 29 May 1979 to Crow, and U.S. Pat. No. 5,101,897, issued on 7 Apr. 1992 to Leismer et al.

It is an object of the present invention to provide a system for anchoring a downhole tool to a casing or tubing within a borehole.

It is an object of the present invention to provide a spiral threaded barrel slip device for anchoring a downhole tool to a casing or tubing within a borehole.

It is an object of the present invention to provide a method for anchoring a downhole tool to a casing or tubing by expanding a spiral threaded barrel slip.

It is another object of the present invention to provide a system with a barrel slip with a spiral threaded inner slip surface and at least one cone with a spiral threaded outer cone surface for anchoring a downhole tool to a casing or tubing within a borehole.

It is still another object of the present invention to provide a system with barrel slip with spiral threaded inner slip surfaces in opposing spiral directions and cones with corresponding spiral threaded outer cone surfaces for each spiral direction to anchor a downhole tool to a casing or tubing.

It is yet another object of the present invention to provide a system with a barrel slip with spiral threaded inner slip surfaces in opposing spiral directions and cones with corresponding spiral threaded outer cone surfaces for each spiral direction locked in a run-in configuration until placed at the correction location in the casing or tubing.

It is yet another object of the present invention to provide a system with a barrel slip with spiral threaded inner slip surfaces in opposing spiral directions and cones with corresponding spiral threaded outer cone surfaces for each spiral direction locked in an expanded configuration.

It is an object of the present invention to provide a method of assembling a system with an expandable spiral threaded barrel slip device for anchoring a downhole tool to a casing or tubing with reduced risk of deformation and damage to the components.

It is an object of the present invention to provide a system with a spiral threaded barrel slip device for anchoring a downhole tool to a casing or tubing with greater precision tolerance between spiral threaded surfaces of the barrel slip and cones.

It is an object of the present invention to provide a system with a spiral threaded barrel slip device for anchoring a downhole tool to a casing or tubing with greater distribution of load capacity.

These and other objectives and advantages of the present invention will become apparent from a reading of the attached specification, drawings and claims.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention include a system for anchoring a downhole tool to a casing within a borehole, including a first cone, a second cone, and a slip device. The downhole tool can be a packer or plug or other tool that requires attachment to the casing, wellbore, or tubing in the borehole. The system for anchoring is only one component of the downhole tool, which may include other components, such as sealing members, support rings, ball seats, and others, according to the functionality of the particular type of downhole tool.

The system includes a mandrel, a piston being mounted around the mandrel, and a piston housing being mounted around the piston and the mandrel. The piston is between the mandrel and the piston housing. The mandrel, piston and piston housing can be coaxial. The system also includes a first cone being mounted on the mandrel and having a first spiral threaded outer cone surface. The first spiral threaded outer cone surface is threaded in a first spiral direction. The first cone is moveable along the mandrel according to movement of the piston housing. The system further includes second cone being mounted on the mandrel and having a second spiral threaded outer cone surface. The second spiral threaded outer cone surface is threaded in a second spiral direction, and the first spiral direction is opposite the second spiral direction.

Embodiments of the system further include a slip device having an outer slip surface and an inner slip surface. The slip device fits over the first cone and the second cone and the mandrel. The inner slip surface is comprised a first spiral threaded inner slip surface and a second spiral threaded inner slip surface. There is also an end housing affixed to the mandrel. The end housing is removably engaged to the second cone so as to prevent rotation of the second cone and to prevent movement of the second cone along the mandrel. The second cone has a secured axial and rotationally locked position on the mandrel by the end housing.

In the present invention, the slip device has a run-in configuration and a set configuration. The slip device starts in the run-in configuration and can be expanded into the set configuration. In the run-in configuration, the first spiral threaded inner slip surface is in spiral threaded engagement with the first spiral threaded outer cone surface and the second spiral threaded inner slip surface is in spiral threaded engagement with the second spiral threaded outer cone surface. The first cone is positioned closer to the second cone than the initial distance within the slip device in the set configuration. The first spiral threaded inner slip surface is now in raised spiral threaded engagement with the first spiral threaded outer cone surface and the second spiral threaded inner slip surface is now in raised spiral threaded engagement with the second spiral threaded outer cone surface in the set configuration.

Additional embodiments of the present invention include the slip device having a gripping means for the casing or borehole or being a barrel slip or both. The system can also add a key member to the second cone to further support the rotational locked engagement between the second cone and the slip device. The system can also add a locking ring to further support the one-directional axial movement of the first cone toward the second cone.

The present invention further includes a method for assembling the system for anchoring the downhole tool. The method includes positioning a slip device around the mandrel, mounting the first cone around the mandrel and into the slip device by rotating the first cone in the first spiral direction, and mounting the second cone around the mandrel and into the slip device by rotating the second cone in the second spiral direction. The end housing is affixed to place the second cone in the secured position axially and rotationally. The piston housing and piston are mounted on the mandrel to engage the first cone with the slip device in the run-in configuration. The method of assembly further including installing the supplement locking support components, such as the key member and locking ring.

Embodiments of the present invention further include the method of anchoring the system to the casing or borehole, after the steps of assembling the system. The downhole tool with the system is deployed with the slip device in the run-in configuration until being positioned at a desired location in the casing. Then, the method includes exerting an axial force on the piston housing and positioning the first cone closer to the second cone. The slip device is placed in a set configuration with an extended diameter greater than the initial diameter to hold the downhole tool at the desired location. The rotational force in the first spiral direction by the first cone is offset by a counter rotational force in the second spiral direction by the second cone. The end housing prevents rotation of the second cone and movement of the second cone along the mandrel.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a sectional view of a prior art anchoring apparatus for a downhole tool.

FIG. 2 is a perspective view of a downhole tool with prior art slips for anchoring.

FIG. 3 is a side elevation view of a prior art barrel slip anchoring apparatus.

FIG. 4 is a longitudinal sectional view of the prior art barrel slip anchoring apparatus of FIG. 3, showing the run-in configuration.

FIG. 5 is a longitudinal sectional view of the prior art barrel slip anchoring apparatus of FIG. 3, showing the expanded configuration.

FIG. 6 is a side elevation view of an embodiment of the system for anchoring, showing the slip device in the run-in configuration, according to the present invention.

FIG. 7 is a side elevation view of an embodiment of the system for anchoring, showing the slip device in the set configuration, according to the present invention.

FIG. 8 is a sectional view of an embodiment of the system for anchoring, showing the slip device in the run-in configuration, according to the present invention.

FIG. 9 is a sectional view of an embodiment of the system for anchoring, showing the slip device in the set configuration, according to the present invention.

FIG. 10 is a side elevation view of embodiments of the mandrel, the first cone, the second cone, and the slip device of the system for anchoring, according to the present invention.

FIG. 11 is a longitudinal sectional view of embodiments of the mandrel, the first cone, the second cone, and the slip device of the system for anchoring, according to the present invention with the slip device in the run-in configuration.

FIG. 12 is a longitudinal sectional view of embodiments of the mandrel, the first cone, the second cone, and the slip device of the system for anchoring, according to the present invention with the slip device in the set configuration.

FIG. 13 is an upper perspective view of an embodiment of a key member of the system for anchoring, according to the present invention.

FIG. 14 is a partial sectional view of embodiments of the key member, second cone and slip device of the system for anchoring, according to FIG. 13.

FIG. 15 is an enlarged sectional view of embodiments of the locking ring, the piston housing, the mandrel, the first cone, and the slip device of the system for anchoring.

FIG. 16 is an upper perspective view of an embodiment of the system for anchoring with the slip device in the run-in configuration, according to the present invention.

FIG. 17 is an upper perspective view of an embodiment of the system for anchoring with the slip device in the transition between the run-in configuration and the set configuration, including arrows indicating forces, according to the present invention.

FIG. 18 is an upper perspective view of an embodiment of the system for anchoring with the slip device in the set configuration, according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The conventional barrel slip is a prior art anchoring component for a downhole tool, such as a plug or packer. The conventional barrel slip has ratchet engagement between the slip device and the cones, according to the straight threaded surfaces between the slip device and the cones. The consequences of this ratchet engagement by straight threaded surfaces include limitation on the load capacity of the prior art anchoring component and precarious tight tolerances between the straight threaded surfaces. Furthermore, the assembling and disassembling of the prior art anchoring component is only possible by a force-fit relationship between the conventional barrel slip and cones, which deforms the conventional barrel slip and risks damage. The conventional barrel slip and cones can be damaged before the anchoring component is even used, and the tight tolerances between the straight threaded surfaces are already susceptible to even the slightest damage. The present invention is a system 10 with an expandable spiral threaded slip device 40 for anchoring to the casing with load capacity that is more evenly distributed and avoids the need for tight tolerances between surfaces. Additionally, the system 10 with the expandable spiral threaded slip device 40 can be assembled without deformation and with less risk of damage and with the possibility of disassembly without damage.

The present invention is a system 10 for anchoring a downhole tool to a casing within a borehole, including a mandrel 12, a piston 14, a piston housing, 16, an end housing 18, a first cone 20, a second cone 30, and a slip device 40, as shown in FIGS. 6-18. The downhole tool can be a packer or plug or locking sleeve or other tool for attachment to a casing or tubing of a borehole. The downhole tool may incorporate a single system 10 for anchoring or a plurality of system 10 for anchoring. Depending on the functionality of the downhole tool as a packer or plug, more than one system 10 for anchoring may be needed. The system 10 for anchoring is only a component of the downhole tool. There may be other components, such as sealing members, support rings, ball seats, and others, that determine the functionality of the particular type of downhole tool. The system 10 for anchoring of the present invention can be incorporated into a variety of downhole tools. Any downhole tool that may require anchoring to the casing or tubing may be compatible with the present invention.

Embodiments of the system 10 for anchoring a downhole tool to a casing, according to FIGS. 6-9, include a mandrel 12 having a first mandrel end 13 and a second mandrel end 15 opposite the first mandrel end, a piston 14 being mounted around the mandrel and being moveable from the first mandrel end toward the second mandrel end, and a piston housing 16 being mounted around the piston and the mandrel. The piston is between the mandrel and the piston housing. The mandrel, piston and piston housing can be coaxial. The piston can be actuated by known means, including a pump, switch, and electronic control. Conventional components for these means for actuating the piston can be attached on the mandrel on the first mandrel end opposite the first cone. Various, sealing members, ring members, cones, and slips and shear screws can be installed for the control of the actuation of the piston 14 as the setting tool for the system 10. FIGS. 6-9 show these convention components upstream from the first cone 20.

FIGS. 10-12 show the system 10 also including a first cone 20 being mounted on the mandrel and having a first spiral threaded outer cone surface 22. The first spiral threaded outer cone surface is threaded in a first spiral direction 24. As in FIGS. 6-9, the piston housing 16 is between the first mandrel end 13 and the first cone 20. The first cone 20 is moveable along the mandrel 12 toward the second mandrel end 15 according to movement of the piston housing 16 along the mandrel and toward the second mandrel end. The piston 14 pushes the piston housing 16, and the piston housing pushes the first cone 20. FIGS. 10-12 also show the second cone 30 being mounted on the mandrel and having a second spiral threaded outer cone surface 32. The second spiral threaded outer cone surface is threaded in a second spiral direction 34. The first spiral direction is opposite the second spiral direction, as in FIG. 11. Rotation in the first spiral direction is opposed by rotation in the second spiral direction. The first cone 20 is between the piston housing 16 and the second cone 30.

Embodiments of the system 10 further include the slip device 40 being mounted on the mandrel 12 between the first cone 20 and the second cone 30 and having an outer slip surface 42 and an inner slip surface 44. The slip device 40 fits over the first cone 20 and the second cone 30 and the mandrel 12. There is coaxial relationship of the slip device 40 and the mandrel 12 with the first cone 20 and the second cone 30 between the slip device 40 and the mandrel 12. The inner slip surface 44 is comprised a first spiral threaded inner slip surface 46 and a second spiral threaded inner slip surface 48. The first cone 20 faces toward the second cone 30 within the slip device 40.

FIGS. 6-9 also show an end housing 18 being affixed to the mandrel 12. The second cone 30 is between the end housing 18 and the first cone 20. The end housing 18 is removably engaged to the second cone 30 so as to prevent rotation of the second cone and to prevent movement of the second cone along the mandrel. The end housing 18 locks the second cone 30 in axial position on the mandrel and in rotation around the mandrel 12. The second cone 30 has a secured axial and rotationally locked position on the mandrel by the end housing 18. Similarly, the first cone 20 can be rotationally locked on the mandrel 12, but remains axially moveable by the piston housing 16 and piston 14. There is still a rotational engagement of the slip device to both the first cone 20 and the second cone 30. That is, although the second cone is securing on the mandrel, there can be a rotational force exerted by the second cone 30 on the slip device 40.

The present invention includes the slip device 40 having a run-in configuration and a set configuration. The run-in configuration corresponds to assembling the system 10 for deployment into the casing or wellbore. The set configuration corresponds to anchoring the tool with the system 10 at the desired location in the casing or wellbore. The slip device 40 starts in the run-in configuration and can be expanded into the set configuration. The slip device 40 in the run-in configuration has an initial diameter. This initial diameter would be the smallest diameter for maneuvering through the casing or wellbore. The first spiral threaded inner slip surface 46 is in spiral threaded engagement with the first spiral threaded outer cone surface 22 in the run-in configuration. The second spiral threaded inner slip surface 48 is in spiral threaded engagement with the second spiral threaded outer cone surface 32, also in the run-in configuration. The first cone 20 is positioned at an initial distance from the second cone 30 within the slip device in the run-in configuration, and the second cone 30 is positioned at the secured axial and rotationally locked position on the mandrel 12 by the end housing 18 and within the slip device 40 in the run-in configuration.

The slip device 40 in the set configuration has an extended diameter that allows the slip device 40 to anchor to the casing or walls of the borehole. The extended diameter is larger than the initial diameter. The first cone 20 is positioned closer to the second cone 30 than the initial distance within the slip device 40 along the mandrel 12 in the set configuration. The first spiral threaded inner slip surface 46 is now in raised spiral threaded engagement with the first spiral threaded outer cone surface 22 in the set configuration. The second spiral threaded inner slip surface 48 is now in raised spiral threaded engagement with the second spiral threaded outer cone surface 32 in the set configuration. The second cone 30 is still positioned at the secured axial and rotationally locked position on the mandrel 12 by the end housing 18 and within the slip device 40 in the set configuration. The first cone 20 has moved closer by the piston housing 16 and the piston 14.

FIGS. 16-18 show that a rotational force in the first spiral direction 24 by the first cone 20 on the slip device 40 is offset by a counter rotational force in the second spiral direction 26 by the second cone 30 on the slip device 40. The end housing 18 prevents rotation of the second cone 30 and movement of the second cone 30 along the mandrel 12.

FIGS. 10-12 also show the embodiment of the slip device 40 with the outer slip surface 42 being comprised of a gripping means 49. The outer slip surface 42 has as gripping means 46 for attachment to the casing or tubing or part of the borehole for anchoring. The gripping means 49 can be a toothed surface or textured surface. The gripping means 49 can also be any other known means for gripping, such as an adhesive or protrusions to engage the slip device 40 to the casing or tubing. The load capacity of the system 10 for anchoring of the present invention is distributed along the length of the slip device 40. The load capacity to push the first cone 20 and second cone 30 against the straight threaded engagement is isolated at the concentric rings along the slip device 40, corresponding to the size of the straight threads. The load is focused on these concentric rings; thus, the concentric ring areas must maintain the tight tolerances at each straight thread in order to hold the set configuration in the prior art. Any slight damage to one straight thread weakens the prior art anchoring component. The load capacity is reduced by damage to one single straight thread. In the present invention, the load capacity to push the first cone 20 and the second cone 30 against the spiral threaded engagement is distributed all along the length of the slip device 40 because the spiral threads are all along the length of the slip device 40. The set configuration no longer hinges on one concentric ring of the slip device 40 to maintain the load. The system 10 for anchoring of the present invention has more resilience with the greater distribution of load capacity. Furthermore, the criticality of each straight thread of the prior art is now moot with the continuous spiral thread along the length of the slip device 40.

FIGS. 10-12 show the first spiral threaded inner slip surface 46 being spaced further from the first spiral threaded outer cone surface 22 in the raised spiral threaded engagement than in the spiral threaded engagement of the run-in configuration. The second spiral threaded inner slip surface 48 is also spaced further from the second spiral threaded outer cone surface 32 in the raised spiral threaded engagement than in the spiral threaded engagement of the run-in configuration. The extended diameter of the slip device 40 in the set configuration corresponds the surfaces between the slip device 40 and the cones 20, 30 being pushed further apart as the first cone 20 and the second cone 30 move laterally toward each other within the slip device 40.

Embodiments of the system 10 for anchoring include the piston housing 16 in removable threaded engagement or removable friction fit engagement with the first cone 20, as in FIGS. 6-9. The rotation of the first cone 20 relative to the piston housing 16 can be locked. The first cone 20 can be screwed into the slip device 40, and then the piston housing 16 can be screwed into the first cone 20. The threads do not even have to be the same dimensions. A snap fit and seal ring engagement or even male-female connectors can also friction fit the piston housing 16 to the first cone 20. The locked rotation of the first cone 20 relative to the mandrel 12 by the piston housing 16 isolates any rotational force to the slip device 40. Similarly, the end housing 18 is in removable threaded engagement or friction fit engagement with the second cone 30 so as to lock rotation of the second cone 30 relative to the mandrel 12. The rotation of the second cone 30 relative to the end housing 18 can be locked. Analogously, the second cone 30 can be screwed into the slip device 40, and then the end housing 18 can be screwed into the second cone 30. Again, the threads do not even have to be the same dimensions, and the alternative friction fit engagement, i.e. snap fit, seal ring and male-female connectors, are still available for the second cone 30 being in friction fit engagement with the end housing 18. In addition to the locked rotation of the second cone 30 relative to the mandrel 12 by the end housing 18, there is secured positioning to prevent any axial movement along the mandrel 12. The lack of axial movement allows a counter axial force (See FIG. 17) toward the first cone to become an isolated counter rotational force on the slip device 40.

FIGS. 10-12 show the embodiments of the slip device 40 being a barrel slip. The slip device is comprised of a barrel body 50. The barrel body 50 is comprised of a plurality of ribs 52. Each rib 52 of the plurality of ribs 52 is connected to an adjacent rib 52 of the plurality of ribs 52. The distance between each rib 52 of the slip device 40 expands from the run-in configuration to the set configuration. Spreading the ribs 52 corresponds to the extended diameter of the slip device 40.

Further embodiments of the slip device 40 being comprised of the barrel body 50 includes a slip locking means 54 to maintain the slip device 40 in the run-in configuration. The slip locking means 54 holds the slip device 40 in the run-in configuration at the initial diameter. When the downhole tool reaches the desired location in the casing or tubing, a threshold amount of load is applied to release the slip locking means 54 to allow the slip device 40 to expand from the initial diameter to the extended diameter of the set configuration. FIG. 10 shows the embodiment of the slip locking means 54 being comprised of a plurality of tabs 56 for the barrel body 50 as the slip device 40. Each rib 52 of the plurality of ribs 52 and an adjacent rib 52 are held in position around the first cone 20 and the second 30 cone at the initial diameter by a corresponding tab 56. The plurality of tabs 56 removably connect each rib 52 of the plurality of ribs 52 in the run-in configuration. The tabs 56 are fractured or split by the threshold amount of load applied to release the slip lock means 54 so that the ribs 52 are no longer held at the initial diameter by the tabs 56.

FIGS. 10-14 show a further embodiment of the present invention including a key member 60 being mounted on the second cone 30. The spiral threaded engagement of the run-in configuration and the raised spiral threaded engagement of the set configuration, the system 10 for anchoring must prevent rotation of the slip device 40 relative to the second cone 30. Although the screwing action is advantageous for assembling the system 10 to the run-in configuration, there is a need to prevent a reverse screwing action or un-screwing. The load to push the surfaces along the spiral threaded engagement must not be re-directed to rotation for unscrewing either cone 20, 30 from the slip device 40. The key member 60 on the second cone 30 supplements the secured axial and rotationally locked position of the second cone 30 on the mandrel 12 by the end housing 18.

For the related embodiment of the slip device 40 as a barrel body 50 being comprised of a plurality of ribs 52, as in FIGS. 10-14, the key member 60 is positioned between a first rib 52 and a corresponding first adjacent rib 52 so as to prevent rotation of the second spiral threaded inner slip surface 48 relative to the second spiral threaded outer cone surface 32 with the slip device 40 in the set configuration. In the raised spiral threaded engagement of the set configuration, the load on the slip device 40 to expand the slip device 40 cannot be re-directed to unscrew either the first cone 20 or the second cone 30. FIGS. 13-14 show embodiments of the key member 60. The key member 60 can be comprised of an anchor end 62 and a flange body 64 extending radial to the anchor end 62. The anchor end 62 is attached to the second cone 30 by any known means, such as a threaded screw, adhesive, or bolt. The flange body 64 extends between the rib 52 and the corresponding adjacent rib for preventing rotation of the ribs 52 around the second cone 30. The second cone 30 is further supported to prevent unscrewing from the slip device 40 as a barrel body 50 in both the run-in configuration and the set configuration.

FIGS. 8-9 and 15 show another further embodiment of the present invention including a locking ring 70. When the mandrel 12 has a ratchet threaded portion 17, the locking ring 70 can have a complementary ratchet threaded surface 72 in ratchet engagement around the mandrel 12. The ratchet threaded portion 17 is positioned between the piston housing 16 and the first cone 20 so that the locking ring 70 is also positioned between the piston housing 16 and the first cone 20. The locking ring 70 is in removable engagement to the first cone 20 so as to prevent axial movement of the first cone 20 away from the second cone 30 along the mandrel 12 after the piston 14 has pushed the piston housing 16 to push the first cone 20 toward the second cone 30. The ratchet threaded portion 17 and the complementary ratchet threaded surface 72 can be one-directional ratchet threads so that the locking ring 70 can only move in one direction toward the second cone 30. The locking ring 70 further supports the axial movement of the first cone 20 by the piston housing 16 toward the second cone 20.

FIGS. 8-9 and 11-12 show embodiments of the first cone 20 having a first spiral threaded outer cone surface 22, being threaded in a first spiral direction 24. The first cone 20 is shown on the left side of the system 10, but the first cone 20 could also be placed on the right side. The first cone 20 includes other features that are compatible with the downhole tool. FIGS. 6-7 show various portions within the inner bore of the first cone for attachment and cooperation with other downhole tool components.

FIGS. 8-9 and 11-12 show embodiments of the second cone 30 having a second spiral threaded outer cone surface 32, being threaded in a second spiral direction 34. Similar to the embodiments of the first cone 20, the second cone 30 is shown on the right side of the system 10, but the second cone 30 could also be placed on the left side. The second cone 30 also includes other features that are compatible with the downhole tool. FIGS. 6-7 show various cam portions around the base of the second portion for attachment and cooperation with other downhole tool components.

The present invention does require the first cone 20 to be oriented towards the second cone 30. FIGS. 6-12 and 16-18 show the first cone 20 facing toward the second cone 30 within the slip device 40. The system 10 for anchoring includes the first cone 20 being moveable towards the second cone 30 within the slip device 40. Furthermore, the first spiral direction 24 is opposite the second spiral direction 34. The rotation of the first cone 20 in the first spiral direction 24 can set the first cone 20 within the slip device 40 for the run-in configuration, while rotation of the second cone 30 in the second spiral direction 34 can set the second cone 30 within the slip device 40 for the run-in configuration. In this relationship, when the system 10 for anchoring is assembled, the slip device 40 cannot rotate free from both the front cone 20 and the second cone 30. One rotation direction, such as the first spiral direction 24, will hold the first cone 20 on the slip device 40, while unscrewing the second cone 30. For the opposite rotation direction, such as the second spiral direction 34, the second cone 30 will be held on the slip device 40, while unscrewing the first cone 20.

The present invention further includes a method for assembling the system 10 for anchoring the downhole tool. The method for assembling includes the step of positioning a slip device 40 having an outer slip surface 42 and an inner slip surface 44 around a mandrel 12 having a first mandrel end 13 and a second mandrel end 15 opposite the first mandrel end. The inner slip surface 44 is comprised a first spiral threaded inner slip surface 46 and a second spiral threaded inner slip surface 48, as in FIGS. 6-12 and 16-18. The method next includes the step of mounting a first cone 20 around the mandrel 12 from the first mandrel end 13 and into the slip device 40, the first cone 20 having a first spiral threaded outer cone surface 22 being threaded in a first spiral direction 24. The first spiral threaded outer cone surface 22 is rotated relative to the slip device 40 so as to be in spiral threaded engagement in the first spiral direction 24 with the first spiral threaded inner slip surface 46. Then, a second cone 30 is mounted around the mandrel 12 from the second mandrel end 15 and into the slip device 40 opposite the first cone 20. The second cone 30 has a second spiral threaded outer cone surface 32 being threaded in a second spiral direction 34, and the first spiral direction 24 is opposite the second spiral direction 34. The second spiral threaded outer cone surface 32 is rotated relative to the slip device 40 so as to be in spiral threaded engagement in the second spiral direction 34 with the second spiral threaded inner slip surface 48. The slip device 40 is now in a run-in configuration with an initial diameter.

The method for assembling further includes the step of affixing an end housing 18 around the mandrel 12 from the second mandrel end 15 and engaging the second cone 30 so as to prevent rotation of the second cone 30 and to prevent movement of the second cone 30 along the mandrel 12. Next, the method includes mounting a piston housing 16 around the mandrel 12 from the first mandrel end 13 and engaging the first cone 20, and mounting a piston 14 around the mandrel 12 from the first mandrel end 13 and through the piston housing 16. The piston 14 is between the mandrel 12 and the piston housing 16 with the slip device 40 in the run-in configuration. The first cone 20 is moveable along the mandrel 12 toward the second mandrel end 15 according to movement of the piston housing 16 along the mandrel 12 and toward the second mandrel end 15 by the piston 14.

Embodiments of the method for assembling can also include the step of installing a key member 60 removably mounted on the second cone 30 and extending into the slip device 40 so as to further prevent rotation of the second cone 30 relative to the slip device 40. For the embodiment of the slip device 40 as a barrel slip, the slip device 40 is comprised of a barrel body 50, and the barrel body 50 is comprised of a plurality of ribs 52. Each rib 52 is connected to an adjacent rib 52. The key member 60 is positioned between a rib 52 and a corresponding adjacent rib 52 so as to further prevent rotation of the second spiral threaded inner slip surface 48 relative to the second spiral threaded outer cone surface 32.

Alternate embodiments of the method for assembling address the mandrel 12 having a ratchet threaded portion 17. In that embodiment of the method, a locking ring 70 is installed in ratchet engagement with the ratchet threaded portion 17 around the mandrel and between the piston housing 16 and the first cone 20. The locking ring 70 is in removable engagement to the first cone 20 so as to further prevent backward axial movement of the first cone 20 away from the second cone 30 along the mandrel.

The present invention further includes the method of anchoring the system 10 to the casing or borehole, as in FIGS. 16-18. The method comprises the steps of deploying a downhole tool with the system 10 having the slip device 40 in the run-in configuration, into a casing, and positioning the downhole tool at a desired location in the casing. Then, the method includes exerting an axial force (see FIG. 17) on the piston housing 16 along the mandrel 12 by the piston 14 and positioning the first cone 20 closer to the second cone 30 than the initial distance within the slip device 40 with the piston housing 16. The slip device 40 is placed in a set configuration with an extended diameter by radial forces. The extended diameter is greater than the initial diameter and holds the downhole tool at the desired location. The rotational force in the first spiral direction 24 by the first cone 20 on the slip device 40 is offset by a counter rotational force in the second spiral direction 34 by the second cone 30 on the slip device 40. The end housing 18 prevents rotation of the second cone 30 and movement of the second cone 30 along the mandrel 12.

The method for anchoring further includes the steps of radially extending the outer slip surface 42 further from the first spiral outer cone surface 22 in a raised threaded engagement than in the run-in configuration, and radially extending the outer slip surface 42 further from the second spiral outer cone surface 32 in the raised threaded engagement than in the run-in configuration. The first spiral inner slip surface 46 is in raised threaded engagement with the first spiral outer cone surface 22 in the set configuration, and the second spiral inner slip surface 48 is in raised threaded engagement with the second spiral outer cone surface 32 in the set configuration. For the embodiments of the mandrel 12 having a ratchet threaded portion 17 and the system 10 having a locking ring 70 in ratchet engagement with the ratchet threaded portion 17 around the mandrel 12 and between the piston housing 16 and the first cone 20, the method further includes the step of engaging the first cone 20 with the locking ring 70 along the ratchet threaded portion 17 during the step of positioning the first cone 20 close to the second cone 30 so as to further prevent backward axial movement of the first cone 20 away from the second cone 30 along the mandrel 12.

The present invention may further include reversing the steps of assembling for a method of disassembling. Rotating the first cone 20 in the opposite direction will separate the first cone 20 from the slip device 40. If the first cone 20 was not set properly, then the first cone 20 can be unscrewed from the slip device 40, even if the second cone 30 has already been inserted into the slip device 40. Unlike the prior art, the slip device is not deformed by expansion in order to fit over the straight threads. The slip device does not need to be re-expanded and further damaged in order to replace a cone. The present invention has reduced the risk of damage during assembly, such that disassembly is possible and may result in reuse of the slip device with a different set of cones.

The present invention provides an apparatus for anchoring a downhole tool to a casing or tubing within a borehole, according a spiral threaded engagement and a raised spiral threaded engagement between a slip device and first and second cones. The first cone is moved closer to the second cone within the slip device to expand the slip device from an initial diameter in the run-in configuration to an extended diameter in the set configuration. The initial diameter corresponds to the spiral threaded engagement, and the extended diameter corresponds to the raised spiral threaded engagement.

The spiral threaded engagement can be between a barrel slip with a spiral threaded inner slip surface and cones with spiral threaded outer cone surfaces. The spiral threaded inner slip surface is divided into a first spiral threaded inner slip surface and a second spiral threaded inner slip surface. The spiral direction of the first spiral threaded inner slip surface and the second spiral threaded inner slip surface oppose each other and correspond to the spiral threaded outer cone surfaces of the respective cones. The cones are also facing each other and have a spiral direction opposite to each other.

Further modifications are required beyond the conversion of straight threads to spiral threads, and particularly, the opposing spiral threads. The present invention includes multiple locking systems to prevent premature expansion and unscrewing or reverse rotating the cones from the slip device. The load exerted against the slip device cannot be re-directed to rotate the cones in the opposite directions to release the cones from the slip device. The present invention includes locks for the initial distance between the first cone and the second cone. The present invention includes locks for the ribs of a barrel slip as the slip device. The present invention further includes a key member to further support rotation locking the second cone. The present invention further includes the locking ring to further support one directional axial movement of the first cone.

The present invention provides a method of assembling a spiral threaded apparatus for anchoring a downhole tool to a casing or tubing with reduced risk of deformation and damaging the slip device as a barrel slip. Instead of deforming the components to snap-fit over straight threads, the cones of the present invention are inserted by rotating along the spiral threads. The assembly by screwing further results in possible disassembly by unscrewing. The reverse rotation will remove the cones from the slip device. If the first cone is not set properly, the first cone can be unscrewed from the slip device, even after the second cone has been inserted. In the prior art, the barrel slip is expanded to fit over the cones, and there is no way to remove either cone without damage to the barrel slip, if the cones need to be re-set. There is less risk of damage during disassembly, so some components of the present invention may be reuseable. The barrel slip has not been expanded to snap fit over the cones, and the barrel slip does not have to be damaged to remove one of the cones. The prior art snap-fit engagement of straight threads generally damages components during removal or any disassembly and prevents reuse. Additionally, the spiral threaded engagement and raised spiral threaded engagement distributes load capacity along the slip device, instead of isolating load capacity at the edges of straight threads. With such dependence on these edges of the straight threads, the spiral threads of the present invention are more robust and relax the tight tolerances of the prior art threaded surfaces.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated structures, construction and method can be made without departing from the true spirit of the invention.