Downhole Tool Having Slip Composed of Composite Ring
A single piece composite slip component is disclosed, making it easier and more feasible for milling up a composite plug after use. Moreover, because the composite slip component is one piece during deployment, and not in segments like conventional slip segments, it can better withstand the high speeds and higher fluid velocities and pressures downhole.
This application claims the benefit of U.S. Prov. Appl. 61/877,113, filed 12 Sep. 2013, which is incorporated herein by reference.
BACKGROUND OF THE DISCLOSUREAn oil or gas well includes a bore extending into a well to some depth below the surface. Typically, the bore is lined with tubulars or casing to strengthen the walls of the bore. To further strengthen the walls of the bore, the annular area formed between the casing and the bore is typically filled with cement to permanently set the casing in the bore. The casing is then perforated to allow production fluid to enter the bore and to be retrieved at the surface of the well.
Typically, downhole tools with sealing elements are placed within the bore to isolate the production fluid or to manage production fluid flow through the well. For example, a plug or packer is placed within a bore to isolate upper and lower sections of production zones. Thus, by creating a pressure seal in the bore, these plugs allow pressurized fluids or solids to treat an isolated formation. These tools are usually constructed of cast iron, aluminum, or other alloyed metals, but have a malleable, synthetic element system. The plug or packer system can also be composed of non-metallic components made of composites, plastics, and elastomers.
Slips are a part of these downhole tools, such as plugs and packers, and the slips can also be composed of metallic or non-metallic components. However, metallic slips can cause problems during mill-up operations of the downhole tools in horizontal wells. As one solution to these problems, slip segments composed of composite material can be held on a mandrel of a downhole tool, such as a plug. These composite slip segments are typically held together with bands on the tool's mandrel until actuated to engage the surrounding casing downhole. Additionally, the composite slips segments can have inserts or buttons that are composed of metallic materials (e.g., tungsten carbide or the like) that grip the inner wall of the surrounding casing or tubular. Examples of downhole tools with slip segments with inserts are disclosed in U.S. Pat. Nos. 6,976,534 and 8,047,279.
Conventional composite slips 104a-b include multiple slip segments 110 disposed around the mandrel 102. Bands 112 typically hold the slip segments 110 in place, and the composite segments 110 include one or more metallic inserts 114 in order to engage the casing (12).
During operation, the slip segments 110 move away from the mandrel 102 and compress the inserts 114 against the surrounding casing (12) when the plug 100 is compressed. Examples of the operation of conventional slip components of such a plug 100 are disclosed in U.S. Pat. No. 7,124,831 which is incorporated within in its entirety.
As mentioned, the conventional slip assemblies 104a-b may be composed of cast iron, aluminum, or other alloyed metals. However, in one problem associated with such metallic slip assemblies, it is often times less desirable to use such metallic components due to the mill-ability of the components. For example, plugs 100 are sometimes intended to be temporary and must be removed to access the casing (12). Rather than de-actuating the plug 100 and bringing it to the surface of the well, the plug 100 is typically destroyed with a rotating milling or drilling device.
As the mill contacts the plug 100, the plug 100 is “drilled up” or reduced to small pieces that are either washed out of the bore or simply left at the bottom of the bore. The more metal parts making up the plug 100, the longer the milling operation takes. Furthermore, metallic components like aluminum also typically require numerous trips in and out of the bore to replace worn out mills or drill bits. Also, aluminum mandrels are typically composed of very expensive aerospace grade materials, and are thus not economically feasible for such use.
In another problem, the conventional slip assemblies even if composed of composite materials are oftentimes difficult to manufacture. For example, the conventional slip assemblies 104a-b are often manufactured as multiple, independent segments 110. Then, the slip segments 10 are positioned around the mandrel 102 of the plug 100 and are held together with restraining bands 112 to keep the segments 110 against the mandrel 102 for deploying in the casing 110 until actuated. Although this form of manufacture may work, it is often time-consuming and involves a very complicated manufacturing and assembly process.
Further, other problems associated with using slip segments 110 held by restraining bands 112 arise when the tool 100 is deployed downhole. As is known in the art, downhole conditions vary, and high pressures and high fluid velocities may disengage or render unusable conventional slip assemblies 104a-b. For example, during the deployment of the plug 100, the fluid in the bore may have a high enough pressure and/or may have an increased velocity as it transitions past the slip assembly 104a-b that the slip assembly 104a-b can be damaged and disengage from the mandrel 102, despite being held together by bands 112. That is, the bands 112 may not be strong enough to hold the segments 110 together in certain downhole conditions.
Accordingly, there is a need for a non-metallic slip component that will effectively handle the high temperatures and the high pressures downhole. There is also a need for a slip component that is easier and faster to manufacture, while remaining economically feasible. Finally, there is a need for a non-metallic slip assembly that can withstand the high speeds and fluid velocities during run in on a downhole tool through casing.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
SUMMARY OF THE DISCLOSUREConventional slip components of downhole tools are typically composed of cast iron, aluminum, or other alloyed metals. However, the more metal parts making up the plug (i.e., slip components) the longer the milling operation takes. Also, metallic components like aluminum also typically require numerous trips in and out of the bore to replace worn out mills or drill bits and are typically composed of very expensive aerospace grade materials, and are thus not economically feasible for such use. Therefore, a single piece composite slip component is disclosed, making it easier and more feasible for milling up a plug after use. Moreover, because the composite slip component is one piece during deployment, and not in segments like conventional slip segments, it can better withstand the high speeds and higher fluid velocities and pressures downhole. This is important aspect when pumping down extended reach horizontals.
A downhole apparatus have a mandrel with a cone disposed thereon. In general, the apparatus can be a plug, a packer, a liner hanger, an anchoring device, or a downhole tool.
The single piece composite slip component is disposed on the mandrel and has a cylindrical body with first and second surfaces and first and second ends. The cylindrical body is disposed with the first surface about the mandrel and with the first end adjacent a cone on the mandrel of the downhole tool. In one arrangement, the cylindrical body defines only a single slit extending partially from the first end toward the second end. In another arrangement, the cylindrical body defines only two slits extending partially from the first end toward the second end. These two slits can be disposed on radially opposite sides of the cylindrical body.
The cylindrical body is radially expandable outward from the mandrel through interaction of the first end with the cone, and one or more inserts disposed on the cylindrical body and exposed at the second surface engage in the surrounding tubular wall of casing or the like.
When interacting the first end of the cylindrical body with the cone, the cylindrical body expands radially outward from the tool with the interaction as at least one and not more than two arcuate members by separating the cylindrical body along the one and not more than two slits extending partially from the first end toward a second end of the cylindrical body. The one or more inserts on the cylindrical body engage against the adjacent surface. Load is transmitted from the cone to the cylindrical body, and the load is transmitted from the cylindrical body to the one or more inserts.
To interact with the cone, the first surface can define an incline at the first end. The single or two slits extend a greater distance along the second surface than along the first surface of the cylindrical body. The cylindrical body at the second end can have an interconnection at the slit so that the interconnection can hinge one side of the single slit with an opposite of the single slit. The interconnection can define a triangular cross-section.
A packing element can be disposed on the mandrel, and the cone and the single piece composite slip component can be disposed on an uphole end of the mandrel adjacent the packing element. A second slip can also be disposed on a downhole end of the mandrel adjacent an opposite side of the packing element. This second slip can include a plurality of independent segments disposed about the mandrel.
The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.
Disposed on the mandrel 102, the plug 100 has uphole and downhole slip assemblies 104a-b, cones 106a-b, and backups 108a-b with a packing element 109 disposed between them. The uphole slip assemblies 104a as shown includes the composite slip component 120 according to the present disclosure, while the downhole assembly includes a conventional slip assembly having segments 110 with inserts 114 and held by bands 112.
As best shown in the detailed view of
Regarding the disposition of the slip component 120 and the conventional slip assembly 104b at uphole and downhole ends of the plug 100, the disclosed plug 100 is not limited to this particular configuration. That is, the plug 100 may comprise composite slip components 120 on both uphole and downhole ends, or the plug 100 may comprise a slip component 120 at the downhole end, while having a conventional slip assembly 104b uphole. Accordingly, any other combination of slip component 120 with or without conventional slip assembly 104b can be used on the plug 100.
However, regardless of which is deployed uphole or downhole, it is desired to deploy a slip assembly having greater structural stability (e.g., the disclosed slip component 120) at the uphole end of the plug 100 and to deploy a slip assembly with increased strength at the downhole end of the plug. This is due in part to what the uphole assembly 104a may encounter during run in at high speeds. The uphole assembly 104a may experience more adverse effects from fluid flow or friction during run in of the plug 100 in the casing (12) which could damage a conventional slip assembly with segments. Because the slip component 120 is a continuous cylindrical component, it is less prone to damage during run in.
Choice of what type of assembly to use at the downhole end is also based on the operation of the plug 100. For example, because the downhole slip assembly has to remain in place, braking and engaging the inner bore, while the uphole slip is compressed toward the downhole slip, the downhole slip assembly may experience certain pressures or effects that the uphole slip assembly may not experience. Thus, if the downhole slip assembly cannot withstand certain forces, the downhole slip assembly may disengage from the casing. As a result, the plug 100 may fail during use. For these reasons, the uphole assembly 104a of the present disclosure may use the disclosed slip component 120, while the downhole assembly 104b may use other types of segments 110 and the like.
In operation, the element system 103 of the plug 100 shown in
Further, as the packing element 109 expands to provide a fluid seal between the plug 100 and the casing (12), the slip component 120 and assembly 104b move along the surface of cones 106a-b. As a result, the slip component 120 and assembly 104b will expand outward with respect to the plug 100, thereby being driven into the casing to hold plug 100 in place.
With particular reference to the offset views of
Also, the slip component 120 comprises insert holes 128 that contain inserts 130 disposed within them. In this embodiment, the inserts 130 may be disposed around the cylindrical body 122 of the slip component 120 in a variety of different ways. For example, the inserts 130 can be disposed around the cylindrical body 122 in a way that the inserts 130 are separated by an equal space. Furthermore, the inserts 130 may be aligned in rows, aligned diagonally along cylindrical body 122, or any other configuration. The purpose of the configuration of the inserts 130 around the cylindrical body 122 is to allow as many inserts 130 as possible to be disposed therein, while maintaining the structural soundness of the composite material.
The slip component 122 is manufactured in a manner similar to the continuous fiber winding process described in U.S. Pat. No. 7,124,831, which is used for manufacturing plugs and is incorporated herein by reference. In general, the manufacturing process involves wet winding a continuous fiber around a temporary mandrel to form the cylindrical body 122 of the slip component. The fiber is preferably wound in an overlapping lattice structure. The resin impregnated fiber is then heated, cured, and cooled so the cylindrical body 122 can be removed from the temporary mandrel and machined. The outer and inner diameters of the cylindrical body 122 may be machined to a certain size, tolerance, or smoothness. Also, any of the various slits 124, holes 128, and the like may be machined in the cylindrical body 122. These and any other additional steps available in the art can be used so that slip component can be installed on the mandrel 102 of the plug 100 with other components for future deployment in the harsh environment downhole.
As show in
As can be seen in
With an understanding of the plug 100 and the disclosed slip component, discussion turns to further details of the slip component 120.
Furthermore, when the slip component 120 is compressed over its adjacent cone (106a), the slip component 120 will separate along the slits 127 and will fracture, break, or tear along the interconnecting portions 127, creating slip element halves (125a-b) that allow the slip component 120 to expand more efficiently over the conical surface (107a) of the cone (106a). Due to the material makeup of the slip component 120 (i.e., continuous fiber winding as described in U.S. Pat. No. 7,124,831), when the slip component 120 is pushed over the cone (106a), the slip component 120 flexes and conforms to the larger radius of the casing (12), while the inserts (130) penetrate the casing (12) and anchor the slip component 120 in place.
Also, since the slip component 120 is one piece during running in the hole, and does not comprise independent segments like a conventional slip assembly of the prior art held together by bands, the slip component 120 can better withstand the high speeds and higher fluid velocities encountered during run in the plug 100. In this regard, allowing the slip component 120 to expand more efficiently over its cone (106a) will allow the slip component halves (125a-b) to more succinctly engage the casing (12). In turn, allowing the slip component 120 to more succinctly engage the casing (12) will allow the inserts (130) to engage the inner surface of the casing (12) and provide an anchor for the plug 100.
Further, the slit elements 124 can extend from either end of the slip component 120, and/or extend thru the inner cylindrical surface (121) with an axial cut that does not penetrate to the outer surface of the slip component 120.
Further, in this view, the insert holes 128 are shown disposed throughout the outer surface of the slip component 120. Moreover, although this embodiment only shows two slit elements 124, there may be one slit 124 or more slits disposed around the circumference of the slip component 120.
The slits 124 are formed to control breakage of the slip component 120 during expansion. Therefore, the depth, the length, the width, and any other characteristics of the slits 124 can be varied depending on the strength of the composite material used, the expected forces encountered during expansion, and other factors. As shown here, the slits 124 are formed on opposite sides of the cylindrical body 122 and extend from a distal end to almost a proximal end of the component 120 adjacent the push ring 105. The slits 124 are defined completely through the thickness of the cylindrical body 122, although this may not be strictly necessary. Additionally, more of the slit 124 may be formed on the outside of the body 122 than the inside so that the interconnecting portions 127 have a triangular cross-section as shown in
Also, the insert hole 128 may be disposed within the outer surface of the slip component 120 at an angle θ. The purpose of disposing inserts 130 at an angle θ is so that when the plug 100 is activated and the slip component 120 is expanded outward and fractured into halves (125a-b) contacting the casing (12) of the bore, the inserts 130 within the slip component halves (125a-b) will engage the casing (12) at an angle to ensure maximum stability of the plug 100 as it is sealed within the casing (12).
Referring first to
As previously described, this engagement of the inserts 130 within the casing 12 provides stability for the plug 100 while in the bore. Further, as can be seen in
Referring to
In the previous embodiment, only the uphole assembly 104a on the plug 100 included the disclosed slip component 120. This is not strictly necessary as will be appreciated herein. For example,
In operation, the composite slip components 120a-b will shift over the conical surfaces 107a-b of the adjacent cones 106a-b until the slip components 120a-b expand, fracture, and fully engage the casing (12). Further as shown in
In previous embodiments, the slip component 120 includes at least two slits 124, although other configurations are possible. For example,
In reference to
The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. It will be appreciated with the benefit of the present disclosure that features described above in accordance with any embodiment or aspect of the disclosed subject matter can be utilized, either alone or in combination, with any other described feature, in any other embodiment or aspect of the disclosed subject matter.
In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.
Claims
1. A downhole apparatus, comprising:
- a mandrel;
- a cone disposed on the mandrel;
- a first slip having a cylindrical body with first and second surfaces and first and second ends, the cylindrical body disposed with the first surface about the mandrel and with the first end adjacent the cone, the cylindrical body defining only a single slit extending partially from the first end toward the second end, the cylindrical body radially expandable outward from the mandrel through interaction of the first end with the cone; and
- one or more inserts disposed on the cylindrical body and exposed at the second surface.
2. The apparatus of claim 1, wherein the first surface defines an incline at the first end.
3. The apparatus of claim 1, wherein the single slit extends a greater distance along the second surface than along the first surface of the cylindrical body.
4. The apparatus of claim 1, wherein the cylindrical body at the second end comprises an interconnection at the single slit, the interconnection hinging one side of the single slit with an opposite of the single slit.
5. The apparatus of claim 1, wherein the interconnection defines a triangular cross-section.
6. The apparatus of claim 1, wherein the apparatus comprises a plug, a packer, a liner hanger, an anchoring device, or a downhole tool.
7. The apparatus of claim 1, comprising a packing element disposed on the mandrel, wherein the cone and the first slip are disposed on an uphole end of the mandrel adjacent the packing element.
8. The apparatus of claim 7, comprising a second slip disposed on a downhole end of the mandrel adjacent an opposite side of the packing element.
9. The apparatus of claim 8, wherein the second slip comprises a plurality of independent segments disposed about the mandrel.
10. A downhole apparatus, comprising:
- a mandrel;
- a cone disposed on the mandrel;
- a cylindrical body having first and second surfaces and having first and second ends, the cylindrical body disposed with the first surface about the mandrel and with the first end adjacent the cone, the cylindrical body defining only two slits extending partially from the first end toward the second end, the cylindrical body radially expandable outward from the mandrel through interaction of the first end with the cone; and
- one or more inserts disposed on the cylindrical body and exposed at the second surface.
11. The apparatus of claim 10, wherein the first surface defines an incline at the first end.
12. The apparatus of claim 10, wherein each of the two slit extends a greater distance along the second surface than along the first surface of the cylindrical body.
13. The apparatus of claim 10, wherein the cylindrical body at the second end comprises interconnections at each of the two slits, the interconnections hinging one side of the each slit with an opposite of the each slit.
14. The apparatus of claim 10, wherein each of the interconnections defines a triangular cross-section.
15. The apparatus of claim 10, wherein the apparatus comprises a plug, a packer, a liner hanger, an anchoring device, or a downhole tool.
16. The apparatus of claim 10, comprising a packing element disposed on the mandrel, wherein the cone and the first slip are disposed on an uphole end of the mandrel adjacent the packing element.
17. The apparatus of claim 10, comprising a second slip disposed on a downhole end of the mandrel adjacent an opposite side of the packing element.
18. The apparatus of claim 17, wherein the second slip comprises a plurality of independent segments disposed about the mandrel.
19. The apparatus of claim 10, wherein the only two slits are disposed on radially opposite sides of the cylindrical body.
20. A method of setting a downhole tool against an adjacent surface, the method comprising:
- interacting a first end of a cylindrical body with a surface of the tool;
- expanding the cylindrical body radially outward from the tool with the interaction as at least one and not more than two arcuate members by separating the cylindrical body along at least one and not more than two slits extending partially from the first end toward a second end of the cylindrical body;
- engaging one or more inserts on the cylindrical body against the adjacent surface;
- transmitting load from the surface to the cylindrical body; and
- transmitting the load from the cylindrical body to the one or more inserts.
Type: Application
Filed: Sep 12, 2014
Publication Date: Mar 12, 2015
Inventors: Matthew R. Stage (Houston, TX), Jonathan A. Young (Houston, TX), Wesley C. Pritchett (Liberty, TX), James A. Rochen (Waller, TX)
Application Number: 14/484,378
International Classification: E21B 33/129 (20060101); E21B 23/06 (20060101); E21B 33/124 (20060101); E21B 23/01 (20060101);