PIG AND PIGGING METHODS FOR GAS PIPELINES

Abstract

A deformable pig and method of pigging are disclosed. The deformable pig is an outer shell having a hollow, spherical shape and a deformable core material contained within the outer shell. The deformable core material may be a shape memory polymer foam which will contour to bends in a pipeline being treated. This enables effective cleaning of the pipeline while inhibiting the pig from getting stuck in the pipeline. Alternatively, the deformable pig may be made from the shape memory polymer foam and be rectangular shaped without an outer shell material.

Claims

1. A deformable pig comprising a shell and a deformable core material.

2. The deformable pig as claimed in claim 1 wherein the deformable core material is a shape memory effect polymer foam.

3. The deformable pig as claimed in claim 1 wherein the deformable core material comprises a material selected from the group consisting of polyurethanes, polysilicons and polyethylenes.

4. The deformable pig as claimed in claim 2 wherein the deformable core material further comprises a wax.

5. The deformable pig as claimed in claim 1 wherein the deformable core material comprises a polymer selected from the group consisting of polytetrafluoroethylene, polyactide and ethylene-vinyl acetate.

6. The deformable pig as claimed in claim 1 wherein the deformable core material comprises a silicone-wax hybrid.

7. The deformable pig as claimed in claim 6 wherein the silicone-wax hybrid is formed by combining silicone, wax and a salt.

8. The deformable pig as claimed in claim 1 wherein the shell is selected from the group consisting of fiber reinforced composites, polystyrene, metal and polymers selected from the group consisting of polyesters, polycarbonates, polyamides, and polyurethanes.

9. The deformable pig as claimed in claim 8 wherein the shell further comprises metal brushes,

10. The deformable pig as claimed in claim 1 wherein the deformable core material is bonded to the shell through a bond selected from the group consisting of covalent and noncovalent bonding.

11. The deformable pig as claimed in claim 1 which is rectangular in shape.

12. The deformable pig as claimed in claim 1 wherein the deformable core material is a polystyrene mixed with a polymer selected from the group consisting of EVA, PVA, vinyl alcohol, ethylene EVOH and polyvinylidene chloride.

13. The deformable pig as claimed in claim 1 further comprising a shell that is fitted with sensors.

14. The deformable pig as claimed in claim 13 wherein the sensors are selected from the group consisting of sensors for monitoring corrosion, monitoring pipeline defect, pipeline imaging, and for generating power.

15. The deformable pig as claimed in claim 1 further comprising a shell loaded with a corrosion inhibitor.

16. The deformable pig as claimed in claim 1 wherein the shell is textured.

17. A deformable pig comprising an outer shell having a hollow, spherical shape and a deformable core material contained within the outer shell.

18. The deformable pig as claimed in claim 17 wherein the deformable core material is a shape memory effect polymer foam.

19. The deformable pig as claimed in claim 17 wherein the deformable core material comprises a material selected from the group consisting of polyurethanes, polysilicons and polyethylenes.

20. The deformable pig as claimed in claim 19 wherein the deformable core material further comprises a wax.

21. The deformable pig as claimed in claim 17 wherein the deformable core material comprises a polymer selected from the group consisting of polytetrafluoroethylene, polyactide and ethylene-vinyl acetate.

22. The deformable pig as claimed in claim 17 wherein the deformable core material comprises a silicone-wax hybrid.

23. The deformable pig as claimed in claim 22 wherein the silicone-wax hybrid is formed by combining silicone, wax and a salt.

24. The deformable pig as claimed in claim 17 wherein the shell is selected from the group consisting of fiber reinforced composites, polystyrene, metal and polymers selected from the group consisting of polyesters, polycarbonates, polyamides, and polyurethanes.

25. The deformable pig as claimed in claim 24 wherein the outer shell further comprises metal brushes.

26. The deformable pig as claimed in claim 17 wherein the deformable core material is bonded to the shell through a bond selected from the group consisting of covalent and non-covalent bonding.

27. The deformable pig as claimed in claim 17 wherein the deformable core material is a polystyrene mixed with a polymer selected from the group consisting of EVA, PVA, vinyl alcohol, ethylene EVOH and polyvinylidene chloride.

28. The deformable pig as claimed in claim 17 further comprising an outer shell that is fitted with sensors.

29. The deformable pig as claimed in claim 28 wherein the sensors are selected from the group consisting of sensors for monitoring corrosion, monitoring pipeline defect, pipeline imaging, and for generating power.

30. The deformable pig as claimed in claim 17 further comprising an outer shell loaded with a corrosion inhibitor.

31. The deformable pig as claimed in claim 17 wherein the shell is textured.

32. A method for cleaning a pipeline comprising pigging the pipeline with a pig comprising a deformable pig comprising an outer shell having a hollow, spherical shape and a deformable core material contained within the outer shell.

33. The method as claimed in claim 32 wherein the pig is launched into the pipeline from a pig launcher.

34. The method as claimed in claim 32 wherein the pig contacts interior walls of the pipeline.

35. The method as claimed in claim 32 wherein the pipeline contains a material selected from the group consisting of natural gas, refined products and crude oil.

36. The method as claimed in claim 32 wherein the method is performed at least on time per year.

37. The method as claimed in claim 32 wherein the pig is passing through the pipeline at speed of 10 to 17 feet per second

38. The method as claimed in claim 32 wherein the deformable core material is a shape memory effect polymer foam.

39. The method as claimed in claim 32 wherein the deformable core material comprises a material selected from the group consisting of polyurethanes, polysilicons and polyethylenes.

40. The method as claimed in claim 33 wherein the deformable core material further comprises a wax.

41. The method as claimed in claim 32 wherein the deformable core material comprises a polymer selected from the group consisting of polytetrafluoroethylene, polyactide and ethylene-vinyl acetate.

42. The method as claimed in claim 32 wherein the deformable core material comprises a silicone-wax hybrid.

43. The method as claimed in claim 42 wherein the silicone-wax hybrid is formed by combining silicone, wax and a salt.

44. The method as claimed in claim 1 wherein the outer shell is selected from the group consisting of fiber reinforced composites, polystyrene, metal and polymers selected from the group consisting of polyesters, polycarbonates, polyamides, and polyurethanes.

45. The method as claimed in claim 44 wherein the outer shell further comprises metal brushes.

46. The method as claimed in claim 32 wherein the deformable core material is bonded to the shell through a bond selected from the group consisting of covalent and noncovalent bonding.

47. The method as claimed in claim 32 wherein the deformable core material is a polystyrene mixed with a polymer selected from the group consisting of EVA, PVA, vinyl alcohol, ethylene EVOH and polyvinylidene chloride.

48. The method as claimed in claim 32 further comprising an outer shell that is fitted with sensors.

49. The method as claimed in claim 48 wherein the sensors are selected from the group consisting of sensors for monitoring corrosion, monitoring pipeline defect, pipeline imaging, and for generating power.

50. The method as claimed in claim 32 further comprising an outer shell loaded with a corrosion inhibitor.

51. The method as claimed in claim 32 wherein the shell is textured.

52. A method for maintaining a functional line for conveying fluid comprising introducing a deformable pig into the pipeline wherein the deformable pig comprises an outer shell having a hollow, spherical shape and a deformable core material contained within the outer shell.

53. The method as claimed in claim 52 wherein the pig is launched into the pipeline from a pig launcher.

54. The method as claimed in claim 52 wherein the pig contacts interior walls of the pipeline.

55. The method as claimed in claim 52 wherein the pipeline contains a material selected from the group consisting of natural gas, refined products and crude oil.

56. The method as claimed in claim 52 wherein the method is performed at least on time per year.

57. The method as claimed in claim 52 wherein the pig is passing through the pipeline at speed of 10 to 17 feet per second

58. The method as claimed in claim 52 wherein the deformable core material is a shape memory effect polymer foam.

59. The method as claimed in claim 52 wherein the deformable core material comprises a material selected from the group consisting of polyurethanes, polysilicons and polyethylenes.

60. The method as claimed in claim 59 wherein the deformable core material further comprises a wax.

61. The method as claimed in claim 52 wherein the deformable core material comprises a polymer selected from the group consisting of polytetrafluoroethylene, polyactide and ethylene-vinyl acetate.

62. The method as claimed in claim 52 wherein the deformable core material comprises a silicone-wax hybrid.

63. The method as claimed in claim 62 wherein the silicone-wax hybrid is formed by combining silicone, wax and a salt.

64. The method as claimed in claim 52 wherein the shell is selected from the group consisting of fiber reinforced composites, polystyrene, metal and polymers selected from the group consisting of polyesters, polycarbonates, polyamides, and polyurethanes.

65. The method as claimed in claim 64 wherein the outer shell further comprises metal brushes.

66. The method as claimed in claim 52 wherein the deformable core material is bonded to the shell through a bond selected from the group consisting of covalent and non-covalent bonding.

67. The method as claimed in claim 52 wherein the deformable core material is a polystyrene mixed with a polymer selected from the group consisting of EVA, PVA, vinyl alcohol, ethylene EVOH and polyvinylidene chloride.

68. The method as claimed in claim 52 further comprising an outer shell that is fitted with sensors.

69. The method as claimed in claim 68 wherein the sensors are selected from the group consisting of sensors for monitoring corrosion, monitoring pipeline defect, pipeline imaging, and for generating power.

70. The method as claimed in claim 52 further comprising an outer shell loaded with a corrosion inhibitor.

71. The method as claimed in claim 52 wherein the shell is textured.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a schematic showing a pig having a deformable shell and core per the invention.

[0033] FIG. 2 is a schematic showing the deformable pig in various deformations as may be encountered in a pipeline.

[0034] FIG. 3 is a schematic of a deformable pig with various functional objects integrated therein.

[0035] FIG. 4 is schematic of a deformable pig comprising core shape memory polymer foam.

[0036] FIG. 5 is a schematic of a pipeline that contains bends and the relative positions of a deformable pig comprising core shape memory polymer foam,

DETAILED DESCRIPTION OF THE INVENTION

[0037] FIG. 1 is a schematic of a deformable pig that comprises an outer shall having a hollow, spherical shape and a deformable core material that is contained within the outer shell. The deformable pig 10 will comprise the outer shell A which is a hollow, spherical shape. This allows for inclusion of a core shape memory polymer foam material B to be present inside the hollow. Typically the deformable pig 10 has the dimensions that are suitable for the diameter of the pipeline that is undergoing the pigging operation.

[0038] FIG. 2 shows the deformable pig as described in FIG. 1 in various configurations. The designations A and B are the same as employed for use in the description of FIG. 1. Deformable pig 20 shows the deformable pig as a round spherical shape as it would look when launched into the pipeline to be treated.

[0039] Deformable pig 30 shows a compressed deformable pig as it may encounter a change in the dimensions of the pipeline being treated. Likewise, deformable pig 40 is compressed in a different manner as it contours itself to fit the pipeline that is being treated.

[0040] FIG. 3 depicts the deformable pig 50 with a variety of sensors and instrumentation. Typically one or more of these devices may be present in the deformable pig 50 as well as all of them being present. The designations A and B are as described again for FIG. 1 with the outer shell A contacting the inner lining of the pipeline that is being treated by the deformable pig 50.

[0041] Cameras labeled 51 and 52 may be employed to provide visual verification of the surface of the pipeline that is being treated. The deformable core material B may be configured to store inhibitor 53 which can be released as a corrosion inhibitor for example if corrosion is detected. This is facilitated by the inhibitor release functionality 54 as may be built into the outer shell material of the deformable pig 50.

[0042] A dynamo 55 may be present inside of the deformable core material B or straddling between the deformable core material B and the outer shell A. This dynamo can produce electricity which can power the devices and sensors that are present in or on the deformable pig 50.

[0043] The deformable pig 50 may also have a corrosion sensing functionality 56 on the surface of outer shell material A. These sensors can detect pitting and other corrosion in the inner walls of the pipeline so that the operator can determine if there is a need for addition of corrosion inhibitor or more stringent restorative efforts.

[0044] A lot of pipelines are fabricated from steel and are buried underground or undersea. Given these circumstances it can be difficult to have radio communications with the pig. However, deformable pig 50 can contain a data transmitter 57 which is present in the deformable core material B and can gather and transmit various data to the operator of the pipeline after the deformable pig has been retrieved from the pipeline. This data can include the actual coordinates that the pig traversed during its run in the pipeline. It can include any visual or other footage captured by the cameras 51 and 52, as well as any corrosion or pitting data that is captured by the corrosion sensing functionality 56.

[0045] FIG. 4 is a schematic showing a rectangular block of core shape memory polymer foam 60 that can be deployed as the deformable pig. Unlike the spherical shaped deformable pig that has been described above, there is no outer shell present.

[0046] FIG. 5 is a depiction of a pipeline C that has bends in it. These bends can be due to the actual physical construction of the pipeline where bends are build in to accommodate naturally occurring phenomena or because of ground shifts and other natural occurrences that cause the pipeline to bend in spots.

[0047] The rectangular block of core shape memory foam as described above is labeled 60 and operates as the deformable pig. This depiction shows the progression of the deformable pig 60 through the pipeline from left to right noting that at least two points there is a slight bend in the pipeline which the deformable pig not only provides cleaning but also traverses these bends which traditional pigs may not accomplish.

[0048] While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims in this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the invention.