EXPANDABLE BACKUP SYSTEM FOR COMPOSITE FRAC PLUGS

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. The present application claims priority benefit of U.S. Provisional Application No. 63/383,800 filed Nov. 15, 2023, the entirety of which is incorporated by reference herein and should be considered part of this specification.

BACKGROUND

In the field of hydrocarbon production, hydraulic fracturing or “fracing” is a process of stimulating a hydrocarbon producing well by fracturing the surrounding rock with a hydraulically pressurized fluid of water, sand and chemicals. During fracing it is commonly necessary to isolate each zone so as to only provide the pressurized fluid and sand to the desired location within the well. This is due to the potential for the well to be quite long and therefore the pumping and material required to therefore frac the entire well string would be too large.

In a variety of well fracturing applications, a wellbore is initially drilled and cased. One common method of splitting the well up into the manageable zones is to provide a plug below the zone to be fraced and thereafter perforating the well bore liner in that zone with an explosive or the like. Thereafter the pressurized fluid and sand may be pumped to that location to perform the frac. This process may be repeated in successive steps upward from the bottom of the well to successively frac each zone that is desired. In essence, multiple frac plugs may be deployed to enable fracturing at different well zones. Each plug comprises a sealing element which is deformed into sealing engagement with the surrounding casing. The sealing element may be formed of an elastomeric material or metal material which is deformed in a radially outward direction until forming a permanent seal with the inside surface of the casing.

SUMMARY

According to one or more embodiments of the present disclosure, a frac plug for use within a cased well. The frac plug comprising a mandrel and a sealing element disposed around the mandrel. An outer backup ring disposed around the mandrel and adjacent to the sealing element. A ductile inner backup ring disposed between the sealing element and the outer backup ring. A cone disposed around the mandrel and adjacent to the outer backup ring. A slip assembly that, when the frac plug is set within the cased well, travels along the cone and expands radially to allow buttons disposed in slips of the slip assembly to engage the casing of the well.

According to one or more embodiments of the present disclosure, a method of fracturing a well. The method comprising disposing a frac plug within a bore of the well. Setting the frac plug to compress a sealing element disposed around a mandrel creating a sealing engagement with the surrounding casing and deforming a ductile inner backup ring of the frac plug into an outer backup ring of the frac plug to cover any exposed gaps in the outer backup ring.

According to one or more embodiments of the present disclosure, a system for isolating a zone in a wellbore with a frac plug for directing fracturing fluid through perforations. The frac plug comprising a mandrel and a sealing element disposed around the mandrel. An outer backup ring disposed around the mandrel and adjacent to the sealing element. A ductile inner backup ring disposed between the sealing element and the outer backup ring. A cone disposed around the mandrel and adjacent to the outer backup ring. A slip assembly that, when the frac plug is set within the cased well, travels along the cone and expands radially to allow buttons disposed in slips of the slip assembly to engage the casing of the well.

However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein.

FIG. 1 is a schematic illustration of an example of a downhole tool deployed in a wellbore according to one or more embodiments of the present disclosure.

FIG. 2 is a cross-sectional view of a frac plug according to one or more embodiments of the present disclosure.

FIG. 3 is an enlarged cross-sectional view of a portion of the frac plug of FIG. 2.

FIG. 4 is an isometric view of the frac plug of FIG. 2.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the apparatus and/or method may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

In the specification and appended claims: the terms “connect,” “connection,” “connected,” “in connection with,” “connecting,” “couple,” “coupled,” “coupled with,” and “coupling” are used to mean “in direct connection with” or “in connection with via another element.” As used herein, the terms “up” and “down,” “upper” and “lower,” “upwardly” and “downwardly,” “upstream” and “downstream,” “uphole” and “downhole,” “above” and “below,” and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments of the disclosure.

Referring generally to FIG. 1, an embodiment of a downhole tool 20 is illustrated deployed in a well 21. According to one or more embodiments of the present disclosure, the downhole tool 20 is a frac plug. For example, the frac plug 20 may be deployed in a wellbore 22 to facilitate a fracturing operation. In the example illustrated, the frac plug 20 is deployed in the wellbore 22 so as to isolate a zone of the wellbore 22 so that fracturing fluid 24 may be directed through perforations 26 and into a surrounding formation 28 uphole of the frac plug 20 for fracturing of the surrounding formation 28. It should be noted that the frac plug 20 according to one or more embodiments of the present disclosure may be used in many types of wellbores, such as deviated, e.g., horizontal, wellbores to facilitate fracturing of desired well zones along the horizontal or otherwise deviated wellbore.

Still referring to FIG. 1, the wellbore 22 may be lined with a casing 30, and each frac plug 20 may be actuated to grip into and seal against the casing 30, thereby sealing or substantially restricting flow of the fracturing fluid 24 downhole of the frac plug 20 in the wellbore 22. As a result, during a fracturing operation, the fracturing fluid 24 is directed through the perforations 26 into the surrounding formation 28 while the frac plug 20 remains anchored to the casing 30. Once the fracturing operation is completed and a given frac plug 20 is no longer of use, the frac plug may be milled and removed from the wellbore 22.

Referring now to FIG. 2 is a cross-sectional view of a frac plug 200 according to one or more embodiments of the present disclosure is shown. Specifically, FIG. 2 shows the frac plug 200 in an unset position. According to one or more embodiments, the frac plug 200 may include a mandrel 202, a slip assembly 204, a cone 206, a sealing element 208, and an outer backup ring 210 disposed around the mandrel 202.

In one or more embodiments, the outer backup ring 210 is disposed adjacent the sealing element 208, which may radially expand against an inner wall of the casing 30 and create a circumferential barrier to keep the sealing element 208 from extruding. Additionally, the outer backup ring 210 may be integrally formed with the cone 206. In other embodiments, the outer backup ring 210 may be separate from the cone 206. In one or more embodiments, the outer backup ring 210 may be an angled segmented backup ring, such as that described in U.S. Pat. No. 9,739,106, which is incorporated herein by reference. The frac plug 200 also includes an internal locking mechanism 212, such as a lock rings or a ratcheting mechanism. The internal locking mechanism 212 keeps the sealing element 208 axially compressed and retains the outer backup ring 210 and slip assembly 204 against the casing 30 after the frac plug 200 is set within the casing 30, as described in more detail below.

Turning now to FIG. 3, FIG. 3 is an enlarged cross-section of the frac plug 200. As described above, the frac plug includes the mandrel 202, the sealing element 208, and the outer backup ring 210. The frac plug 200 also includes an inner backup ring 300 positioned between the outer backup ring 210 and the sealing element 210. In one or more embodiments, the inner backup ring 300 is a ductile, non-metallic backup ring. For example, the inner backup ring 300 may be a polyetheretherketone (“PEEK”) backup ring. In other embodiments, the inner backup ring 300 may be a ductile, metal backup ring. When the frac plug 200 is set within the wellbore, as described in more detail below, the inner backup ring 300 deforms into the outer backup ring 210 and cone 206 without fracturing, covering any exposed gaps in the outer backup ring 210.

Turning now to FIG. 4, FIG. 4 is an isometric view of the frac plug 200 of FIG. 2. As shown in FIG. 4, the slip assembly 204 of the frac plug 200 may include a plurality of slips 400. Further, each slip 216 may include one or more buttons 402 disposed in the slip. Similarly, the outer backup ring 210 includes multiple segments 404 that each include at least one button 406 disposed therein. The segments 404 create the outer backup ring 212 illustrated in FIGS. 2-3.

When the frac plug 200 is compressed from a run-in-hole (RIH) unset position to a set position, the slip assembly 204 travels along the cone 206, causing the slip assembly 204 to radially expand. The radial expansion of the slip assembly 204 causes the buttons 402 disposed in the slips 400 to grip and bite into the inner surface of the casing 30. Further, when the frac plug 200 is in the set position, the sealing element 208 is deformed into sealing engagement with the surrounding casing 30. Additionally, the transition from the unset position to the set position, the segments 404 of the outer backup ring 210 break apart, rotate, and extend radially to create a backup for the sealing element 208 that reduces or prevents extrusion of the sealing element 208. Gaps can be created between the segments 404 when the segments 404 break apart, rotate, and extend radially to create a backup for the sealing element 208. The inner backup ring 300 will deform between the segments 404 of the outer backup ring 210 and the sealing element closing any gaps created during setting of the frac plug 200. The buttons 406 on one or more segments 404 also grip and bite into the inner surface of the casing 30.

According to one or more embodiments of the present disclosure, the sealing element 208 may be formed of an elastomeric material or metal material, which is deformed in a radially outward direction until forming a permanent seal with the inside surface of the casing 30. Due to the gripping and biting of the buttons 402, 406 and the sealing of the sealing element 208, the frac plug 200 is able to be effectively anchored to the inside surface of the casing 30 when the frac plug 200 is in the set position. The frac plug 200 may remain anchored to the inside surface of the casing 30 during a fracturing operation, and after the fracturing operation, the frac plug 200 may be drilled out, as previously described.

Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.