Fracturing port collar for wellbore pack-off system, and method for using same

• US 20020195248A1
• Filed: 02/11/2002
• Published: 12/26/2002
• Est. Priority Date: 05/15/2001
• Status: Active Grant

• Current Assignee: Weatherford Technology Holdings, LLC (Weatherford International PLC)
• Original Assignee: Weatherford/Lamb Incorporated (Weatherford International PLC)
• Inventors: Giroux, Richard L., Ingram, Gary D., Hoffman, Corey E.
• Granted Patent: US 6,695,057 B2
• Time in Patent Office: Days
• US Class Current: 166/308.1
• CPC Class Codes: E21B 33/124 Units with longitudinally-spaced plugs for isolating the intermediate space
• CPC Class Codes: E21B 43/26 by forming crevices or fractures

Abstract

A collar for injecting fluid, such as a formation treating fluid, into a wellbore, and a method for using same. The collar is disposed between the upper and lower packing elements of a pack-off system during the treatment of an area of interest within a wellbore. The collar first comprises an inner mandrel running essentially the length of the collar. The inner bore of the collar is in fluid communication with the annular region between the collar and the surrounding perforated casing by a set of actuation ports. A second set of ports, known as frac ports, is disposed within the mandrel. In accordance with one aspect of the invention, the collar further comprises a tubular case which substantially seals the frac ports in a first position, and slidably moves along the outer surface of the mandrel in order to expose the frac ports in a second position. In operation, the upper and lower packing elements are set at a first fluid pressure level. Upon application of a second greater fluid pressure level, the upper and lower packing elements are further separated in accordance with a designed stroke length, thereby exposing the frac ports.

Claims

1. A fracturing port collar for use with a pack-off system within a wellbore, the fracturing port collar being disposed between an upper packing element and a lower packing element of the pack-off system, the fracturing port collar comprising:

a tubular inner mandrel having an inner surface and an outer surface, and defining a bore within the inner surface, the bore being placed in fluid communication with the outer surface of the mandrel by at least one packer actuation port;

at least one frac port for placing the inner surface and the outer surface of the mandrel in fluid communication with one another;

a tubular case disposed along a portion of the tubular inner mandrel, the tubular case being slidably movable relative to the mandrel between a first position and a second position, wherein the tubular case substantially seals the at least one frac port in its first position, and exposes the at least one frac port in its second position.

2. The fracturing port collar of claim 1, further comprising a biasing member for biasing the tubular case to substantially seal the at least one frac port.

3. The fracturing port collar of claim 3, wherein the biasing member is a spring.

4. The fracturing port collar of claim 3, wherein the upper packing element and the lower packing element are set, at least in part, through hydraulic pressure injected through the bore of the mandrel.

5. The fracturing port collar of claim 4, wherein the tubular case is disposed around the mandrel, and is slidably movable along the outer surface of the mandrel.

6. The fracturing port collar of claim 5, wherein the upper packing element and the lower packing element are set at a first pressure level;

and

wherein the fracturing port collar is configured to telescopically extend along a desired stroke length at a second greater pressure level in response to separation between the upper packing element and the lower packing element.

32. The fluid placement port collar of claim 3, wherein the upper packing element and the lower packing element are set, at least in part, through hydraulic pressure injected through a bore of the mandrel.

33. The fluid placement port collar of claim 32, wherein the tubular case is disposed around the mandrel, and is slidably movable along the outer surface of the mandrel.

34. The fluid placement port collar of claim 33, wherein the upper packing element and the lower packing element are set at a first pressure level;

and

wherein the fluid placement port collar is configured to telescopically extend along a desired stroke length at a second greater pressure level in response to separation between the upper packing element and the lower packing element.

35. The fluid placement port collar of claim 34, wherein the telescopic extension occurs between the tubular mandrel and the tubular case such that the tubular case is moved from the first position to the second position.

36. The fluid placement port collar of claim 34, wherein the case slidably moves along the outer surface of the mandrel between its first and second positions.

37. The fluid placement port collar of claim 36, wherein the fracturing port collar is run into the wellbore on a string of coiled tubing.

38. The fluid placement port collar of claim 37, wherein the at least one packer actuation port is disposed within the mandrel of the fluid placement port collar.

39. The fracturing port collar of claim 38, wherein the at least one packer actuation port is disposed within the mandrel immediately above the at least one wall port above the tubular case.

7. The fracturing port collar of claim 7, wherein the telescopic extension occurs between the tubular inner mandrel and the tubular case such that the tubular case is moved from its first position to its second position.

8. The fracturing port collar of claim 7, wherein the case slidably moves along the outer surface of the mandrel between its first and second positions.

9. The fracturing port collar of claim 8, wherein the fracturing port collar is run into the wellbore on a string of coiled tubing.

10. The fracturing port collar of claim 9, wherein the at least one packer actuation port is disposed within the mandrel of the frac port collar.

11. The fracturing port collar of claim 10, wherein the at least one packer actuation port is disposed within the mandrel immediately above the at least one frac port above the tubular case.

13. The fracturing port collar of claim 12, wherein the second fluid pressure level causes the upper packing element and the lower packing element to separate along a stroke length designed within the fracturing collar, thereby placing the inner surface of the mandrel in fluid communication with the outer surface of the mandrel.

14. The fracturing port collar of claim 13, wherein:

The second fluid pressure level is greater than the first fluid pressure level; and

the frac port collar is configured to telescopically extend along the stroke length at the second greater fluid pressure level in response to the separation between the upper packing element and the lower packing element.

15. The fracturing port collar of claim 14, wherein the telescopic extension occurs between the tubular inner mandrel and the first case.

16. The fracturing port collar of claim 15, wherein the fracturing port collar is run into the wellbore on a string of coiled tubing.

17. The fracturing port collar of claim 16, wherein the inner surface of the mandrel is in fluid communication with the string of coiled tubing.

18. The fracturing port collar of claim 17, wherein the outer surface of the mandrel has an enlarged outer diameter portion which defines an upper shoulder and a lower shoulder.

19. The fracturing port collar of claim 18, further comprising:

a top sub, the top sub defining a tubular body disposed around the mandrel above the first case; and

a second case, the second case defining a tubular body that is also slidably movable along the outer surface of the mandrel.

20. The fracturing port collar of claim 19, wherein the at least one packer actuation port is disposed in the mandrel between a bottom end of the top sub and an upper end of the first case.

21. The fracturing port collar of claim 20, wherein the first case comprises an upper body portion, a lower extension member, and a shoulder at a bottom end of the upper body portion.

22. The fracturing port collar of claim 21, wherein the stroke length is defined by the distance between the shoulder of the first case and the upper shoulder of the enlarged outer diameter portion of the mandrel.

23. The fracturing port collar of claim 22, further comprising a biasing member urging the first case and the second case in an upward position;

and

wherein the first case and the second case are moved downwardly along the outer surface of the mandrel in response to the second fluid pressure level.

24. The fracturing port collar of claim 23, further comprising a nipple, the nipple defining a tubular body disposed around the outer surface of the mandrel below the enlarged outer diameter portion of the mandrel, the nipple being threadedly connected to the lower extension member of the first case proximate to an upper end of the nipple, and being threadedly connected to the second case proximate to a lower end of the nipple.

25. The fracturing port collar of claim 24, further comprising a stop ring at a lower end of the mandrel;

and

wherein the biasing member defines a spring disposed around the outer surface of the mandrel held in compression between the stop ring and the nipple.

27. The fluid placement port collar of claim 26, wherein the wall port closure member is movable in response to changes in fluid flow rate.

28. The fluid placement port collar of claim 27, wherein the wall port closure member defines a tubular case disposed along a portion of the tubular mandrel, the tubular case being slidably movable relative to the mandrel between the first position and the second position, and wherein the tubular case substantially seals the at least one wall port in its first position, and exposes the at least one wall port in its second position.

29. The fluid placement port collar of claim 27, wherein the tubular mandrel has an inner surface and an outer surface, and wherein the tubular mandrel further comprises at least one packer actuation port for placing the inner surface of the tubular mandrel into constant fluid communication with the outer surface of the tubular mandrel.

30. The fluid placement port collar of claim 29, further comprising a biasing member for biasing the tubular case in its first closed position.

31. The fluid placement port collar of claim 30, wherein the biasing member is a spring.

12. A fracturing port collar for use with a straddle pack-off system within a wellbore, the fracturing port collar being disposed between an upper packing element and a lower packing element of the straddle pack-off system, the fracturing port collar comprising:

an inner mandrel defining a tubular body, the mandrel having an inner surface defining a bore, and an outer surface;

at least one packer actuation port within the mandrel for placing the inner surface of the mandrel in fluid communication with the outer surface of the mandrel;

a first case defining a tubular body, the first case slidably moving along the outer surface of the mandrel;

at least one frac port in the mandrel, the frac port being substantially sealed by the first case at a first fluid pressure level between the upper packing element and the lower packing element, but being exposed so as to place the inner surface of the mandrel in fluid communication with the outer surface of the mandrel at a second fluid pressure level between the upper packing element and the lower packing element.

26. A fluid placement port collar for use within a wellbore, the fluid placement port collar being disposed in a tubular assembly between an upper packing element and a lower packing element of the tubular assembly, the fluid placement port collar comprising:

a tubular mandrel having a wall with at least one wall port through the wall; and

a wall port closure member disposed along a portion of the tubular mandrel and being movable relative to the mandrel between a first position and a second position, wherein the port closure member substantially closes the at least one wall port in the first position and substantially opens the at least one wall port in the second position.

40. A method for injecting formation treatment fluid into an area of interest within a wellbore, the method comprising the steps of:

running a pack-off system into the wellbore, the pack-off system having a fracturing port collar disposed between an upper packing element and a lower packing element, the fracturing port collar comprising;

a tubular inner mandrel having an inner surface and an outer surface, and defining a bore within the inner surface, the bore being placed in fluid communication with the outer surface of the mandrel by at least one packer actuation port;

at least one frac port for placing the inner surface and the outer surface of the mandrel in fluid communication with one another; and

a tubular case disposed around a portion of the tubular inner mandrel, the tubular case being slidably movable along the outer surface of the mandrel between a first position and a second position, wherein the tubular case substantially seals the at least one frac port in its first position, and exposes the at least one frac port in its second position;

positioning the pack-off system within the wellbore adjacent an area of interest;

injecting an actuating fluid into the pack-off system at a first fluid pressure level so as to set the upper and lower packing elements;

injecting an actuating fluid into the pack-off system at a second greater fluid pressure level so as to cause the case to slide along the outer surface of the mandrel from its first position to its second position;

thereby exposing the at least one frac port; and

injecting a formation treating fluid into the pack-off system through the exposed at least one frac port.

41. The method of claim 40, wherein the inner surface of the mandrel is in fluid communication with a working string.

42. The method of claim 41, further comprising a biasing member for biasing the tubular case to substantially seal the at least one frac port.

43. The method of claim 42, wherein the biasing member is a spring.

44. The method of claim 43, wherein the fracturing port collar is configured to telescopically extend along a desired stroke length at the second greater pressure level in response to separation between the upper packing element and the lower packing element.

45. The method of claim 44, wherein the telescopic extension occurs between the tubular inner mandrel and the tubular case.

46. The method of claim 45, wherein the telescopic extension occurs when the tubular case moves from its first position to its second position.

47. The method of claim 46, wherein the fracturing port collar is run into the wellbore on a string of coiled tubing.

48. The method of claim 46, wherein the at least one packer actuation port is disposed within the mandrel of the frac port collar.

49. The method of claim 48, wherein the at least one packer actuation port is disposed within the mandrel proximate to the at least one frac port collar.

50. A method for placing fluid into an area of interest within a wellbore, the method comprising the steps of:

running a pack-off system into the wellbore, the pack-off system having a port collar disposed between an upper packing element and a lower packing element, the port collar comprising;

a tubular mandrel having a wall with at least one wall port through the wall;

a wall port closure member disposed along a portion of the tubular mandrel, and being slidably movable relative to the mandrel between a first position and a second position, wherein the wall port closure member substantially closes the at least one wall port in the first position, and substantially opens the at least one wall port in the second position;

positioning the pack-off system within the wellbore adjacent an area of interest;

flowing fluid into the pack-off system to set the upper and lower packing elements and to move the wall port closure member from the first position to the second position thereby substantially opening the at least one wall port; and

placing a fluid into the pack-off system and through the opened at least one wall port.

51. The method of claim 50, wherein:

the tubular mandrel has an inner surface and an outer surface;

the tubular mandrel further comprises at least one packer actuation port for placing the inner surface of the tubular mandrel in fluid communication with the outer surface of the tubular mandrel, the at least one packer actuation port being disposed immediately above the at least one wall port; and

the tubular mandrel is in fluid communication with a working string.

52. The method of claim 51, wherein the wall port closure member defines a tubular case disposed along a portion of the tubular mandrel, the tubular case being slidably movable relative to the mandrel between the first position and the second position, and wherein the tubular case substantially seals the at least one wall port in the first position, and substantially opens the at least one wall port in the second position.

53. The method of claim 52, wherein the port collar further comprises a biasing member for biasing the tubular case to substantially seal the at least one frac port, the biasing member defining a spring.

54. The method of claim 53, wherein the port collar is configured to telescopically extend along a desired stroke length at the second greater pressure level in response to separation between the upper packing element and the lower packing element.

55. The method of claim 54, wherein the telescopic extension occurs between the tubular mandrel and the tubular case when the tubular case moves from the first position to the second position.

56. The method of claim 55, wherein the working string is a string of coiled tubing.