Fracture Plug

Abstract

A fracture plug having V-shaped recessions in a housing and complementary wedges is disclosed. The V-shaped recessions are broader at a top of the fracture plug and narrower toward the bottom and the wedges are complementary to the V-shaped recessions. The wedges have a similar thickness and radius as the housing and the wedges sit within an envelope defined by an exterior and interior radius of the housing.

Description

BACKGROUND

Downhole fracturing has become a common practice in today's oilfield. One important component fracturing operations is plugs, known as frac plugs. Frac plugs are deployed into a well at a certain depth in order to seal a zone of the well with sufficient strength to withstand the pressures applied during the fracturing operation. There are many existing frac plugs in today's market, but many of them are inefficient or expensive. There is a need in the art for an improved frac plug design.

SUMMARY

Embodiments of the present disclosure are directed to a fracture plug including a cone comprising a complete cylindrical member defining an interior diameter and an outer diameter, the cone having a conical surface, and a packing element surrounding a portion of the conical surface and being configured to expand as the packing element is urged against the conical surface. The fracture plug also includes a housing comprising an incomplete cylindrical member having substantially the same interior diameter and outer diameter as the cone. A difference between the interior diameter and outer diameter defines a thickness of the housing in a radial dimension. The incomplete cylindrical member includes a V-shaped recession having a proximal narrow portion and a distal broad portion, wherein proximal and distal are defined relative to the cone. The fracture plug also includes a wedge positioned in the V-shaped recession and being configured to move from the distal broad portion of the V-shaped recession to the proximal narrow portion and to expand the housing to set the plug in a well. The wedge has substantially the interior diameter and outer diameter as the housing.

Further embodiments of the present disclosure are directed to a fracture plug including a housing formed of a cylindrical member having an inner diameter and an outer diameter. The housing has a V-shaped recession with a narrow portion at a first axial end of the housing and a broad portion at a second axial end of the housing. The V-shaped recession defines a slope, and the housing has a radial thickness defined between the inner and outer diameter. The fracture plug also includes a wedge positioned in the V-shaped recession and having at least approximately the same inner diameter and outer diameter as the housing, the same slope as the V-shaped recession, and the same thickness as the housing. Urging the wedge toward the narrow portion of the V-shaped recession in the housing causes the housing to expand to set the fracture plug.

Further embodiments of the present disclosure are directed to a method of setting a fracture plug in a well. The method includes positioning a fracture plug in the well, the fracture plug comprising a cylindrical housing with one or more recessions that are broader at a top of the housing and narrower at a bottom of the housing. The fracture plug further comprising one or more wedges positioned in the recessions. The wedges have a similar thickness and radius as the housing but are shorter in an axial direction than the housing. The method also includes urging the wedges downward along the recessions such that the wedges expand the housing radially to set the fracture plug.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side view of a frac plug according to embodiments of the present disclosure.

FIG. 2 is a side view of the frac plug according to further embodiments of the present disclosure in which the plug has been fully set.

FIG. 3 is an isometric end view of the plug according to further embodiments of the present disclosure.

FIG. 4 is an isometric illustration of embodiments of the present disclosure directed to a plug including complimentary wedges.

FIG. 5 is a cross-sectional view of the plug of FIG. 4 in a set position according to embodiments of the present disclosure.

FIG. 6 is a cross-sectional view of the plug according to embodiments of the present disclosure in which the ball has not yet been seated in the plug.

FIG. 7 is a cross-sectional view of a frac plug having an internal ball seat according to embodiments of the present disclosure.

FIG. 8 shows the plug with a ball in place and the plug set.

DETAILED DESCRIPTION

FIG. 1 is a side view of a frac plug 100 according to embodiments of the present disclosure. The frac plug 100 is also referred to herein as a plug 100. For purposes of explanation and not limitation, the plug 100 is oriented such that the left-hand side of FIG. 1 is downhole and the right is uphole. It is to be appreciated, however, that in some embodiments the plug 100 can be inverted. The frac plug 100 includes a housing 102 that is a generally cylindrical piece of material that has sufficient strength to withstand pressures required in a downhole environment. The materials of the various components herein can vary, and can include some (or all) dissolvable or degradable components. The housing 102 can include buttons 104 on an exterior surface to enhance the plug's ability to grip an interior surface in a well, such as a casing or an open hole surface.

The housing 102 can be an incomplete cylindrical member, meaning that it does not form a complete circle; rather, the housing 102 has a V-shaped recession. The V-shaped recession has a narrow portion 106 toward the left of the picture (which may also be a downhole direction) and a broad portion 108 toward the right side. The frac plug 100 can also include a wedge 110 sized and positioned within the V-shaped recession such that when the wedge is urged to the left the housing is urged radially and circumferentially outward, expanding the plug 100 and setting the plug 100.

The wedge 110 and housing 102 can have an interior diameter (ID) and an outer diameter (OD) that are substantially coextensive with one another. The housing 102 and wedge 110 can have a complementary cylindrical shape in which the wedge 110 has similar interior contours and exterior contours such that the wedge 110 and housing 102 together have a uniform shape.

The frac plug 100 can also include a packing element 112 which can be an elastomeric member. There is also a cone 114 downward of the housing 102 which supports the packing element 112 with a conical surface 116 that urges the packing element 112 outward as the cone 114 and housing 102 are moved together during setting. The frac plug 100 can be set using a wireline adapter kit (“WLAK”) or other suitable means that urge the wedge downward and the cone upward.

FIG. 2 is a cross-sectional view of the frac plug 100 according to further embodiments of the present disclosure in which the plug has been fully set. The wedge 110 is shown in a fully-deployed position at the far left, the housing 102 has reached the cone 114 and urged the packing element 112 onto the cone 114. The housing and the cone can have corresponding sloped surfaces to facilitate this engagement. It can be seen that the wedge 110 is relatively short when compared to the housing 102 and travels approximately twice its length from the unset run-in-hole position (shown in FIG. 1) and the set position shown here.

The radius of the housing 102 is expanded slightly as the wedge 110 is driven downward to set the plug 100. The radius of the wedge 110 can be similar to the unset radius, the set radius, or an intermediate radius somewhere between the set and unset radius of the housing 102.

FIG. 3 is an isometric end view of the plug 100 according to further embodiments of the present disclosure. The wedge 110 and housing 102 engage with one another along a circumferentially-facing surface at an edge of the V-shaped recession, and that edge can have a complimentary shape. Shown here there is a convex end 120 on the housing 102 and a concave end 122 on the wedge. In other embodiments the convexity and concavity can be reversed. In other embodiments the shape can be rounded, or have other angled surfaces that correspond with one another to facilitate the wedge moving edgewise along the housing and into place as the plug is set. In some embodiments the surfaces are keyed correspondingly.

FIG. 1 shows a single wedge. FIGS. 2 and 3 show two wedges at diametrically opposite positions. In other embodiments there may be three, four, or more wedges.

FIG. 4 is an isometric illustration of embodiments of the present disclosure directed to a plug 140 including complimentary wedges. The plug 140 includes female wedges 142 at a distal end of the plug, and male wedges 144 at a proximal end. The female wedges 142 are narrower at a distal end and wider nearer the proximal end, whereas the male wedges 144 are narrower toward the distal end and wider near the proximal end. In this embodiment there are three female wedges and three male wedges. The wedges are sloped in a complimentary manner to allow the wedges to slide relative to one another as the plug is set. The wedges will also expand radially and circumferentially as the wedges are urged together. The plug 140 can include a shear ring 150 that holds the wedges in place during transport and run-in-hole and is designed to fail to allow the wedges to move relative to one another.

The female wedges have a packing element segment 146 on a proximal end, and the male wedges 144 also have a packing element 148 on a proximal end. When the plug 140 is set by moving the wedges toward one another, the packing elements will overlap at least partially, and in some embodiments fully to provide a seal. The plug 140 can also include buttons 152.

The plug 140 includes a cone 154 at the proximal end to which the male wedges 144 are secured. The cone 154 can also serve as a ball seat once the plug 140 is set. The ball can be dropped and set on the cone 154 to pressure up for a fracturing operation.

FIG. 5 is a cross-sectional view of the plug 140 of FIG. 4 in a set position according to embodiments of the present disclosure. The male and female wedges are shown now with the distal end of the female wedges separated due to the angle of the wedges. The packing element 148 can be seen here. It can have a profile that includes a first portion 160 on the outside of the cone, a second portion 162 as the base, and a third portion 164 extending into the seat portion. The cone 154 can have a metal-to-metal sealing surface, but the third portion 164 is below to provide a flexible and secure seal. The packing element on the male wedges can be similar, although not shown to great advantage here.

FIG. 6 is a cross-sectional view of the plug 140 according to embodiments of the present disclosure in which the ball has not yet been seated in the plug. Pressure for a fracturing operation can be applied to the ball which urges the ball into the position shown in FIG. 5. The buttons are shown engaged with the casing as well due to the setting pressure and the radial and circumferential expansion caused by moving the wedges toward one another. The plug can be set using a WLAK or any other suitable mechanism with sufficient force to urge the wedges into a set position.

FIG. 7 is a cross-sectional view of a frac plug 170 having an internal ball seat according to embodiments of the present disclosure. The plug 170 includes features generally analogous to features of the plug shown in FIGS. 4-6, including female wedges 172, male wedges 174, a first packing element 176, a second packing element 178, buttons 180, and a cone 182. The interior portion of the male wedges 174 include a seat 184 comprised of an inwardly-angled portion configured to seat a ball. FIG. 8 shows the plug 170 with a ball in place and the plug 170 set. The angle and size of the seat can depend on the size of the plug and the ball and can vary as needed. The resulting plug is a relatively short plug which makes for shorter mill times and/or shorter dissolving/degrading times depending on the material and removal mechanism of the plug.

The above is a description of various features and embodiments of the present disclosure which are given to explain certain aspects of the disclosure. Features from various embodiments can be combined together without departing from the scope of the disclosure. Directional descriptions such as up, down, inside, outside, uphole, downhole are given for purposes of explanation and not limitation. Certain aspects of the plugs shown and described herein can be inverted. The number and angle of components can vary.

Claims

1. A fracture plug, comprising: a cone comprising a complete cylindrical member defining an interior diameter and an outer diameter, the cone having a conical surface;a packing element surrounding a portion of the conical surface and being configured to expand as the packing element is urged against the conical surface;a housing comprising an incomplete cylindrical member having substantially the same interior diameter and outer diameter as the cone, wherein a difference between the interior diameter and outer diameter defines a thickness of the housing in a radial dimension, wherein the incomplete cylindrical member includes a V-shaped recession having a proximal narrow portion and a distal broad portion, wherein proximal and distal are defined relative to the cone; anda wedge positioned in the V-shaped recession and being configured to move from the distal broad portion of the V-shaped recession to the proximal narrow portion and to expand the housing to set the plug in a well, wherein the wedge has substantially the interior diameter and outer diameter as the housing.

2. The fracture plug of claim 1 wherein the housing includes a convex circumferentially-facing surface within the V-shaped recession and wherein the wedge has a corresponding convex surface.

3. The fracture plug of claim 1 wherein the housing includes a flat circumferentially-facing surface on a circumferentially-facing surface within the V-shaped recession and wherein the wedge has a corresponding flat surface.

4. The fracture plug of claim 1 wherein the housing includes a keyed circumferentially-facing surface on a circumferentially-facing surface within the V-shaped recession and wherein the wedge has a corresponding keyed surface.

5. The fracture plug of claim 1 wherein the housing has a first length along an axial direction and wherein the wedge has a second length along the axial direction and wherein the second length is less than half of the first length.

6. The fracture plug of claim 1 wherein the housing is rigidly attached to the cone.

7. The fracture plug of claim 1 wherein urging the wedge downward toward the cone causes the packing element to move along the conical surface of the cone.

8. The fracture plug of claim 1, further comprising buttons mounted in an outer surface of the housing to facilitate setting the fracture plug.

9. The fracture plug of claim 1 wherein at least one of the cone, the packing element, the housing, and the wedge are made of a dissolvable material.

10. The fracture plug of claim 1 wherein the V-shaped recession comprises a first V-shaped recession and the wedge comprises a first wedge, the housing including a second V-shaped recession and a second wedge, wherein the first V-shaped recession and second wedge are circumferentially opposite the first V-shaped recession and first wedge.

11. A fracture plug, comprising: a housing formed of a cylindrical member having an inner diameter and an outer diameter, wherein the housing has a V-shaped recession with a narrow portion at a first axial end of the housing and a broad portion at a second axial end of the housing, and wherein the V-shaped recession defines a slope, and further wherein the housing has a radial thickness defined between the inner and outer diameter; anda wedge positioned in the V-shaped recession and having at least approximately the same inner diameter and outer diameter as the housing, the same slope as the V-shaped recession, and the same thickness as the housing, wherein urging the wedge toward the narrow portion of the V-shaped recession in the housing causes the housing to expand to set the fracture plug.

12. The fracture plug of claim 11, further comprising: a cone comprising a cylindrical member having a conical outer surface with a narrow portion proximate the housing and a wide portion distal relative to the housing; anda packing element between the cone and the housing wherein urging the cone toward the wedge and housing causes the packing element to expand along the conical surface to set the fracture plug.

13. The fracture plug of claim 12 wherein the first axial end of the housing is proximate the cone.

14. The fracture plug of claim 11 wherein the housing has two V-shaped recessions and two wedges.

15. The fracture plug of claim 11, further comprising buttons on an exterior surface of the housing.

16. A method of setting a fracture plug in a well, the method including: positioning a fracture plug in the well, the fracture plug comprising a cylindrical housing with one or more recessions that are broader at a top of the housing and narrower at a bottom of the housing, the fracture plug further comprising one or more wedges positioned in the recessions, wherein the wedges have a similar thickness and radius as the housing but are shorter in an axial direction than the housing; andurging the wedges downward along the recessions such that the wedges expand the housing radially to set the fracture plug.

17. The method of claim 16 wherein the fracture plug further comprises a conical surface and an expandable packing element and wherein urging the wedges downward further comprises urging the packing element upon the conical surface to expand the packing element to set the fracture plug.

18. The method of claim 16 wherein the wedges and recessions have a complementary shape at circumferentially-facing edges.

19. The method of claim 18 wherein the complementary shape maintains the wedges radial position relative to the housing as the wedges are urged downward.

20. The method of claim 16 wherein before setting the fracture plug the wedges are in the broader portion of the recession and wherein urging the wedges downward causes the wedges to move toward along the recessions.