US20180094910A1 - Snap-on Liner Retention Device - Google Patents

Abstract

A shaped charge retainer ring for use in containing the liner of a shaped charge and the explosive material.

Description

RELATED APPLICATIONS
• This application claims priority to U.S. Provisional Application No. 62/142,099, filed Apr. 2, 2015.
BACKGROUND OF THE INVENTION
• Generally, when completing a subterranean well for the production of fluids, minerals, or gases from underground reservoirs, several types of tubulars are placed downhole as part of the drilling, exploration, and completions process. These tubulars can include casing, tubing, pipes, liners, and devices conveyed downhole by tubulars of various types. Each well is unique, so combinations of different tubulars may be lowered into a well for a multitude of purposes.
• A subsurface or subterranean well transits one or more formations. The formation is a body of rock or strata that contains one or more compositions. The formation is treated as a continuous body. Within the formation hydrocarbon deposits may exist. Typically a wellbore will be drilled from a surface location, placing a hole into a formation of interest. Completion equipment will be put into place, including casing, tubing, and other downhole equipment as needed. Perforating the casing and the formation with a perforating gun is a well-known method in the art for accessing hydrocarbon deposits within a formation from a wellbore.
• Explosively perforating the formation using a shaped charge is a widely known method for completing an oil well. A shaped charge is a term of art for a device that when detonated generates a focused explosive output. This is achieved in part by the geometry of the explosive in conjunction with a liner in the explosive material. Generally, a shaped charge includes a metal case that contains an explosive material with a concave shape, which has a thin metal liner on the inner surface. Many materials are used for the liner; some of the more common metals include brass, copper, tungsten, and lead. When the explosive detonates the liner metal is compressed into a super-heated, super pressurized jet that can penetrate metal, concrete, and rock.
• A perforating gun has a gun body. The gun body typically is composed of metal and is cylindrical in shape. Within a typical gun tube is a charge holder, which is a tube that is designed to hold the actual shaped charges. The charge holder will contain cutouts called charge holes where the shaped charges will be placed.
• A shaped charge is a term of art for a device that when detonated generates a focused explosive output. This is achieved in part by the geometry of the explosive in conjunction with a liner in the explosive material. Many materials are used for the liner; some of the more common metals include brass, copper, tungsten, and lead. When the explosive detonates the liner metal is compressed into a super-heated, super pressurized jet that can penetrate metal, concrete, and rock.
• Within a typical gun tube is a charge holder, which is a tube that is designed to hold the actual shape charges. The charge holder will contain cutouts called charge holes where the shape charges will be placed. A typical shaped charge is carried in a cylindrical perforating gun.
• Typically, the liner is held within the shaped charge case using an adhesive material. Adhesives present issues during the manufacturing process that incur additional costs and have environmental issues. A need exists for a means of cheaply retaining a liner and explosive material within the shaped charge case without using adhesives. Additionally, it is desirable to place an insulating and non-sparking material on the shaped charge cases for a variety of reasons including safety.
SUMMARY OF EXAMPLES OF THE INVENTION
• An example embodiment is a shaped charge apparatus having a shaped charge case with an axis, an inner surface, an outer surface, and a top surface, and at least one circumferential groove on the outer surface. An L-shaped inner retainer ring with an inner radial surface, an outer radial surface, a lower axial surface, and an upper axial surface may be attached to the shaped charge case. The lower axial surface of the inner retainer ring may be adjacent to the top surface of the shaped charge and the outer radial surface maybe adjacent to the inner surface of the shaped charge. Another L-shaped outer retainer ring having an upper axial surface, a lower axial surface, an inner radial surface, and an outer radial surface, may be attached to the top of the L-shaped inner ring. The inner radial surface of the outer retainer ring may include at least one circumferential groove interfaced with the shaped charge outer surface circumferential groove. The shaped charge may include a liner with an inner surface and an outer surface. The liner may be restrained axially by the inner retainer ring and the outer retainer ring. An explosive material may be located between the outer surface of the liner and the inner surface of the shaped charge case.
• A variation of the example embodiment may include the one circumferential groove on the outside surface of the shaped charge case being a plurality of circumferential grooves. At least one circumferential groove on the inner radial surface of the outer retainer ring may be a plurality of circumferential grooves. The inner retainer ring may be composed of plastic. The outer retainer ring may be composed of plastic. The outer retainer ring and the inner retainer ring may be integrally formed into a single retainer ring. The inner retainer ring may be rated to function up to 400 degrees Fahrenheit. The outer retainer ring may be rated to function up to 400 degrees Fahrenheit. The inner retainer ring may have a low electrical conductivity. The outer retainer ring may have a low electrical conductivity. The inner retainer ring may be manufactured using an additive manufacturing process. The outer retainer ring may be manufactured using an additive manufacturing process.
• Another example embodiment may include a method for making a shaped charge by forming explosive material inside of a shaped charge case, forming a liner over the explosive material, and installing a first retainer ring onto the shaped charge case. The retainer ring may prevent axial movement of the liner and the explosive material within said shaped charge case.
• A variation of the example embodiment may further include installing a second retainer ring to the shaped charged case. The example may include installing the shaped charge in a charge tube. The second retainer ring may prevent axial movement of the first retainer ring. The forming of a liner may result in a substantially frusto-conical shape. The forming of explosive material may result in a substantially frusto-conical shape. The example embodiment may include electrically isolating the shaped charge. It may include manufacturing the first retainer ring. It may include manufacturing the second retainer ring. The manufacturing of the first retainer ring may include an additive manufacturing process. The manufacturing of the second retainer ring may include an additive manufacturing process.
• Another example embodiment may include a shaped charge with a case having an apex end, an open end having a rim, and a cavity extending into case from the open end. It may have a liner fitted into the open end of the case. It may have an electrically insulating ring adapted to fit over the rim of the open end of the case.
• A variation of the example embodiment may include the rim of the open end of the case being substantially circular. It may have a substantially cylindrical inner surface and a substantially cylindrical outer surface and the insulating ring being substantially circular and a substantially cylindrical inner surface and a substantially cylindrical outer surface. The inner surface of the insulating ring may have a smaller diameter than the inner surface of the open end of the case. The outer surface of the rim of the case may have a retention feature. The retention feature may include a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove, or a plurality of circumferential grooves. The inner surface of the rim of the case may have a retention feature that may include a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove or a plurality of circumferential grooves.
• Further variations of the embodiment may include the inner surface of the insulating ring with a retention feature. The retention feature may include a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove, or a plurality of circumferential grooves.
• Further variations of the embodiment may include the outer surface of the insulating ring having a retention feature of a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove, or a plurality of circumferential grooves.
• Further variations of the embodiment disclosed may include the rim of the open end of the case being substantially circular and having a substantially cylindrical inner surface. It may also have a substantially cylindrical outer surface. It may also have the insulating ring having a substantially circular end face, a substantially cylindrical inner wall extending axially from the end face, and a substantially cylindrical outer wall extending axially from the end face. The outer wall of the insulating ring may be adapted to fit outside the outer surface of the rim of the case. The outer wall of the insulating ring may include a retention feature adapted to engage a retention feature on the outer surface of the rim of the case. The inner wall of the insulating ring may be adapted to fit inside the inner surface of the rim of the case. The inner wall of the insulating ring may have a retention feature adapted to engage a retention feature on the inner surface of the rim of the case.
BRIEF DESCRIPTION OF THE DRAWINGS
• For a thorough understating of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings in which reference numbers designate like or similar elements throughout the several figures. Briefly:
• FIG. 1 is cross section of an example perforating gun.
• FIG. 2 is a cross section view of a shaped charge with an inner retainer ring and an outer retainer ring.
• FIG. 3 is a cross section view of a shaped charge with a single retainer ring.
DETAILED DESCRIPTION OF EXAMPLES OF THE INVENTION
• In the following description, certain terms have been used for brevity, clarity, and examples. No unnecessary limitations are to be implied therefrom and such terms are used for descriptive purposes only and are intended to be broadly construed. The different apparatus, systems and method steps described herein may be used alone or in combination with other apparatus, systems and method steps. It is to be expected that various equivalents, alternatives, and modifications are possible within the scope of the appended claims.
• Referring toFIG. 1, atypical perforating gun10 includes agun body11 that houses the shapedcharges12. Thegun body11 containsend fittings16 and20 which secures thecharge tube18 into place. Thecharge tube18 has charge holes23 that are openings where shapedcharges12 may be placed. Thegun body11 has threaded ends14 that allow it to be connected to a series of perforatingguns10 or to other downhole equipment depending on the job requirement. Other design variations may use ends that are bolted together. InFIG. 1, a 60 degree phase gun is shown where each shapedcharge12 is rotated about the center axis by 60 degrees from one shaped charge to the next. Each shapedcharge12 has a correspondingscallop21 milled into thegun body11. Other embodiments of this design are possible including zero degree phase guns, where all the shaped charges are aligned. Other end fittings or connections could be used in lieu of threaded fittings, such as bolted fittings.
• Referring toFIG. 2, an example embodiment is a shapedcharge116 with a shapedcharge case111 having anaxis117, aninner surface108, anouter surface118, and atop surface107. Shapedcharge case111 hascircumferential groove103 on theouter surface118. An L-shapedinner retainer ring115 with an innerradial surface109, an outerradial surface119, a loweraxial surface120, and an upperaxial surface106 is attached to thetop surface107 of the shapedcharge case111. The loweraxial surface120 is adjacent to thetop surface107 of the shapedcharge case111. The outerradial surface119 is adjacent to theinner surface108 of the shapedcharge case111. A L-shapedouter retainer ring102 having an upperaxial surface122, a loweraxial surface121, an innerradial surface104, and an outerradial surface105 engages with the shapedcharge case111. Its innerradial surface104 includes at least onecircumferential groove123 that is interfaced with the shaped charge outer surfacecircumferential groove103. The shapedcharge116 includes aliner113 with aninner surface124 and anouter surface125. Theliner113 is restrained axially by theinner retainer ring115 and theouter retainer ring102. Anexplosive material112 is located between theouter surface125 of theliner113 and theinner surface108 of the shapedcharge case111. The shapedcharge case111 has anapex end126.
• Another example embodiment may include the shapedcharge case111 having anaxis117, aninner surface108, anouter surface118, and atop surface107 and at least onecircumferential retaining feature103 for retaining a ring on the outer surface. The retainingfeature103 may be a circumferential groove, a plurality of circumferential grooves, a thread, a buttress thread, a plurality of ridges, a plurality of detents, a lip, or some other retaining means that is well known in the art.
• A variation of the example embodiment may include a plurality ofcircumferential grooves103 on theoutside surface118 of the shapedcharge case111. Theinner retainer ring115 may be composed of plastic. Theouter retainer ring102 may be composed of plastic. Theinner retainer ring115 may be rated to function up to 400 degrees Fahrenheit. Theouter retainer ring102 may be rated to function up to 400 degrees Fahrenheit. Theinner retainer ring115 probably has a low electrical conductivity. Theouter retainer ring102 probably has a low electrical conductivity. Theinner retainer ring115 may be manufactured using an additive manufacturing process. Theouter retainer ring102 may be manufactured using an additive manufacturing process.
• Another example embodiment includes a method for making a shaped charge by formingexplosive material112 inside of a shapedcharge case111, forming aliner113 over theexplosive material112, and installing afirst retainer ring115 onto the shapedcharge case111. Theretainer ring115 prevents axial movement of theliner113 and theexplosive material112 within said shapedcharge case111.
• A variation of the example embodiment includes installing asecond retainer ring102 to the shaped chargedcase111. It could also include installing the shapedcharge116 in acharge tube18. Thesecond retainer ring102 may prevent axial movement of thefirst retainer ring115. The forming of aliner113 may result in a substantially frusto-conical shape. The formingexplosive material112 may result in a substantially frusto-conical shape. The example embodiment may further include electrically isolating the shapedcharge116. It may include manufacturing thefirst retainer ring115. It may further include manufacturing thesecond retainer ring102. The manufacturing of thefirst retainer ring115 may include an additive manufacturing process. The manufacturing of thesecond retainer ring102 may include an additive manufacturing process.
• Theouter retainer ring102 and theinner retainer ring115 may be integrally formed into asingle retainer ring215 as shown inFIG. 3. Another example embodiment may include a shapedcharge216 with acase211 having anapex end226, anopen end208 having arim230, and a cavity extending into case from theopen end208. Aliner213 is fitted into the open end of the case. An electrically insulatingring215 is fitted over therim230 of theopen end208 of thecase211.Explosive material212 is located between theliner213 and thecharge case211
• A variation of the example embodiment may include therim230 of theopen end208 of thecase211 being substantially circular and having a substantially cylindricalinner surface214. It have include a substantially cylindricalouter surface218. The insulatingring215 may be substantially circular. It may include a substantially cylindricalinner surface231 and a substantially cylindricalouter surface232. Theinner surface231 of the insulatingring215 may have a smaller diameter than theinner surface214 of theopen end208 of thecase211. Theouter surface218 of therim230 of thecase211 may include aretention feature203 such as a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove, or a plurality of circumferential grooves.
• In other examples theinner surface214 of the rim of the case may include aretention feature203 such as a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove, or a plurality of circumferential grooves. Further variations of the embodiment may include theinner surface231 of the insulatingring215 having a retention feature. The retention feature may include aretention feature203 such as a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove, or a plurality of circumferential grooves.
• Further variations of the embodiment may include theouter surface232 of the insulatingring215 has aretention feature233. Theretention feature233 may include aretention feature203 such as a raised circumferential ridge, a plurality of raised circumferential ridges, a circumferential groove, or a plurality of circumferential grooves.
• Further variations of the embodiment disclosed may include therim230 of theopen end208 of thecase211 being substantially circular. It may have a substantially cylindricalinner surface214 and a substantially cylindricalouter surface218. The insulatingring215 may have a substantiallycircular end face202, a substantially cylindricalinner wall235 extending axially from theend face202, and a substantially cylindricalouter wall234 extending axially from theend face202. Theouter wall234 of the insulatingring215 may be adapted to fit outside the outer surface of therim230 of thecase211. Theouter wall234 of the insulatingring215 may include aretention feature233 adapted to engage aretention feature203 on theouter surface218 of therim230 of thecase211. Theinner wall235 of the insulatingring215 may be adapted to fit inside theinner surface214 of therim230 of thecase211. Alternatively, theinner wall235 of the insulatingring215 may include a retention feature adapted to engage a retention feature on the inner surface of therim230 of thecase211.
• Although the invention has been described in terms of particular embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto. Alternative embodiments and operating techniques will become apparent to those of ordinary skill in the art in view of the present disclosure. Accordingly, modifications of the invention are contemplated which may be made without departing from the spirit of the claimed invention.

Claims (59)

What is claimed is:

1. A shaped charge apparatus comprising:

a shaped charge case with an axis, an inner surface, an outer surface, and a top surface; and

at least one circumferential retaining means for retaining a ring on the outer surface.

2. The apparatus ofclaim 1, wherein the at least one retaining means on the outside surface of the shaped charge case is a circumferential groove.

3. The apparatus ofclaim 2, wherein the at least one retaining means is a plurality of circumferential grooves.

4. The apparatus ofclaim 1, wherein the retaining means is a thread.

5. The apparatus ofclaim 4, wherein the thread is a buttress thread.

6. The apparatus ofclaim 1, wherein the retaining means is a plurality of ridges.

7. The apparatus ofclaim 1, wherein retaining means is a plurality of detents.

8. The apparatus ofclaim 1, wherein retaining means is a lip.

9. A shaped charge retaining system comprising:

a shaped charge case with an axis, an inner surface, an outer surface, and a top surface;

at least one circumferential groove on the outer surface;

a L-shaped inner retainer ring with an inner radial surface, an outer radial surface, a lower axial surface, and an upper axial surface, wherein the lower axial surface is adjacent to the top surface of the shaped charge and the outer radial surface is adjacent to the inner surface of the shaped charge;

a L-shaped outer retainer ring having an upper axial surface, a lower axial surface, an inner radial surface, and an outer radial surface, wherein the inner radial surface includes at least one circumferential groove that interfaced with the shaped charge outer surface circumferential groove;

a liner with an inner surface and an outer surface, wherein the liner is restrained axially by the inner retainer ring and the outer retainer ring; and

an explosive material located between the outer surface of the liner and the inner surface of the shaped charge case.

10. The apparatus ofclaim 9, wherein the at least one circumferential groove on the outside surface of the shaped charge case is a plurality of circumferential grooves.

11. The apparatus ofclaim 10, wherein the at least one circumferential groove on the inner radial surface of the outer retainer ring is a plurality of circumferential grooves.

12. The apparatus ofclaim 9, wherein the inner retainer ring is composed of plastic.

13. The apparatus ofclaim 9, wherein the outer retainer ring is composed of plastic.

14. The apparatus ofclaim 9, wherein the outer retainer ring and the inner retainer ring are integrally formed into a single retainer ring.

15. The apparatus ofclaim 12, wherein the inner retainer ring is rated to function up to 400 degrees Fahrenheit.

16. The apparatus ofclaim 13, wherein the outer retainer ring is rated to function up to 400 degrees Fahrenheit.

17. The apparatus ofclaim 9, wherein the inner retainer ring has a low electrical conductivity.

18. The apparatus ofclaim 9, wherein the outer retainer ring has a low electrical conductivity.

19. The apparatus ofclaim 9, wherein the inner retainer ring is manufactured using an additive manufacturing process.

20. The apparatus ofclaim 9, wherein the outer retainer ring is manufactured using an additive manufacturing process.

21. A method for making a shaped charge comprising:

forming explosive material inside of a shaped charge case;

forming a liner over the explosive material; and

installing a first retainer ring onto the shaped charge case, wherein the retainer ring prevents axial movement of the liner and the explosive material within said shaped charge case.

22. The method ofclaim 21, further comprising installing a second retainer ring to the shaped charged case.

23. The method ofclaim 21, further comprising installing the shaped charge in a charge tube.

24. The method ofclaim 22, wherein the second retainer ring prevents axial movement of the first retainer ring.

25. The method ofclaim 21, wherein the forming a liner results in a substantially frusto-conical shape.

26. The method ofclaim 21, wherein the forming explosive material results in a substantially frusto-conical shape.

27. The method ofclaim 21 further comprising electrically isolating the shaped charge.

28. The method ofclaim 21 further comprising manufacturing the first retainer ring.

29. The method ofclaim 21 further comprising manufacturing the second retainer ring.

30. The method ofclaim 28 wherein the manufacturing of the first retainer ring includes additive manufacturing.

31. The method ofclaim 29 wherein the manufacturing of the second retainer ring includes additive manufacturing.

32. A shaped charge comprising:

A case having an apex end, an open end having a rim, and a cavity extending into case from the open end;

a liner fitted into the open end of the case;

an electrically insulating ring adapted to fit over the rim of the open end of the case.

33. The shaped charge ofclaim 32 wherein:

the rim of the open end of the case is substantially circular and comprises a substantially cylindrical inner surface and a substantially cylindrical outer surface; and

the insulating ring is substantially circular and comprises a substantially cylindrical inner surface and a substantially cylindrical outer surface.

34. The shaped charge ofclaim 33 wherein: the inner surface of the insulating ring has a smaller diameter than the inner surface of the open end of the case.

35. The shaped charge ofclaim 33 wherein the outer surface of the rim of the case comprises a retention feature.

36. The shaped charge ofclaim 35 wherein the retention feature comprises a raised circumferential ridge.

37. The shaped charge ofclaim 35 wherein the retention feature comprises a plurality of raised circumferential ridges.

38. The shaped charge ofclaim 35 wherein the retention feature comprises a circumferential groove.

39. The shaped charge ofclaim 35 wherein the retention feature comprises a plurality of circumferential grooves.

40. The shaped charge ofclaim 33 wherein the inner surface of the rim of the case comprises a retention feature.

41. The shaped charge ofclaim 40 wherein the retention feature comprises a raised circumferential ridge.

42. The shaped charge ofclaim 40 wherein the retention feature comprises a plurality of raised circumferential ridges.

43. The shaped charge ofclaim 40 wherein the retention feature comprises a circumferential groove.

44. The shaped charge ofclaim 40 wherein the retention feature comprises a plurality of circumferential grooves.

45. The shaped charge ofclaim 33 wherein the wherein the inner surface of the insulating ring comprises a retention feature.

46. The shaped charge ofclaim 45 wherein the retention feature comprises a raised circumferential ridge.

47. The shaped charge ofclaim 45 wherein the retention feature comprises a plurality of raised circumferential ridges.

48. The shaped charge ofclaim 45 wherein the retention feature comprises a circumferential groove.

49. The shaped charge ofclaim 45 wherein the retention feature comprises a plurality of circumferential grooves.

50. The shaped charge ofclaim 33 wherein the wherein the outer surface of the insulating ring comprises a retention feature.

51. The shaped charge ofclaim 50 wherein the retention feature comprises a raised circumferential ridge.

52. The shaped charge ofclaim 50 wherein the retention feature comprises a plurality of raised circumferential ridges.

53. The shaped charge ofclaim 50 wherein the retention feature comprises a circumferential groove.

54. The shaped charge ofclaim 50 wherein the retention feature comprises a plurality of circumferential grooves.

55. The shaped charge ofclaim 32 wherein:

the rim of the open end of the case is substantially circular and comprises a substantially cylindrical inner surface and a substantially cylindrical outer surface; and

the insulating ring comprises a substantially circular end face, a substantially cylindrical inner wall extending axially from the end face, and a substantially cylindrical outer wall extending axially from the end face.

56. The shaped charge ofclaim 55 wherein the outer wall of the insulating ring is adapted to fit outside the outer surface of the rim of the case.

57. The shaped charge ofclaim 55 wherein the outer wall of the insulating ring comprises a retention feature adapted to engage a retention feature on the outer surface of the rim of the case.

58. The shaped charge ofclaim 55 wherein the inner wall of the insulating ring is adapted to fit inside the inner surface of the rim of the case.

59. The shaped charge ofclaim 55 wherein the inner wall of the insulating ring comprises a retention feature adapted to engage a retention feature on the inner surface of the rim of the case.

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