Auto adjusting well control system and method

• US 6,595,287 B2
• Filed: 10/05/2001
• Issued: 07/22/2003
• Est. Priority Date: 10/06/2000
• Status: Expired due to Term

• Current Assignee: Weatherford Technology Holdings, LLC (Weatherford International PLC)
• Original Assignee: Weatherford/Lamb Incorporated (Weatherford International PLC)
• Inventors: Fisher, Danny
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): BOMAR, THOMAS S
• Application Number:
  US09/972,390
• Publication Number:
  US 20020074118A1
• Time in Patent Office: 655 Days
• Field of Search: 166/250.15, 166/372, 166/263, 166/53
• US Class Current: 166/250.15
• CPC Class Codes: E21B 43/12 Methods or apparatus for controlling the flow of the obtained fluid to or in wells E21B43/25 takes precedence; valve arrangements E21B34/00

Abstract

A programmable controller for operating an artificial lift well is provided to monitor and operate a variety of analog and digital devices. An on-cycle of the well is initiated based on a pressure differential measured between a casing pressure and a sales line pressure. When a predetermined ON pressure differential is observed, the controller initiates the on-cycle and open a motor valve to permit fluid and gas accumulated in the tubing to eurged out of the well. Thereafter, the controller initiates a mandatory flow period and maintains the motor valve open for a period of time. The valve remains open as the system transitions into the sales time period. During sales time, the controller monitors the gas flow through an orifice disposed in the sales line. A differential pressure transducer is used to measure a pressure differential across the orifice. When the measure pressure differential is less than or equal to a predetermined OFF pressure differential, the controller initiates the off cycle. The off cycle starts with a mandatory shut-in period to a low the plunger to fall back into the well. Thereafter, the well remains in the off-cycle until the controller receives a signal that the ON pressure differential has developed. In another aspect, the controller may adjust the operating parameters of the well based on the completion of the cycle.

Claims

1. A method of operating a well having an on time and an off time cycle, comprising:

measuring a first pressure differential;

comparing the first pressure differential to a first stored value;

opening a valve between a tubing and a sales line when the first pressure differential is at least the same as the first stored value, the valve permitting pressurized gas to flow from the tubing into the sales line;

sensing a completion of a portion of the cycle;

measuring a second pressure differential across two points in the sales line;

comparing the second pressure differential to a second stored value;

closing the valve when the second pressure differential is less than or equal to the second stored value; and

adjusting one or more of the stored values.

2. The method of claim 1, herein the first pressure differential is measured between a casing pressure an a sales line pressure.

3. The method of claim 2, wherein the one or more stored values are adjusted prior to beginning a subsequent cycle.

4. The method of claim 3, wherein the portion of the cycle is the arrival of a plunger at a predetermined location in the tubing.

5. The method of claim 1, further comprising maintaining the valve open for a first time period after sensing the completion of a portion of the cycle.

6. The method of claim 5, further comprising adjusting the first time period for which the valve is maintained open nor to beginning a subsequent cycle.

7. The method of claim 1, further comprising maintaining the valve closed for a first time period after closing the valve.

8. The method of claim 7, further comprising maintaining the valve open for a second time period after sensing the completion of a portion of the cycle.

9. The method of claim 1, wherein the portion of the cycle is the arrival of a plunger at a predetermined location in the tubing.

10. The method of claim 9, wherein the arrival of the plunger is sensed within a first time period.

11. The method of claim 10, wherein the arrival of the plunger is sensed within a second time period if the arrival of the plunger was not sensed in the first time period.

12. The method of claim 11, wherein adjusting one or more of the stored values comprises increasing the first stored value if the arrival of the plunger was not sensed within the second time period.

13. The method of claim 11, wherein adjusting one or more of the stored values comprises increasing the second stored value if the arrival of the plunger was not sensed within the second time period.

14. The method of claim 1, wherein adjusting one or more of the stored values comprises decreasing the first stored value.

15. The method of claim 14, further comprising decreasing the second stored value.

16. The method of claim 15, further comprising maintaining the valve open for a first time period after sensing the arrival of the plunger.

17. The method of claim 16, further comprising adjusting the first time period for which the valve remains open prior to beginning a subsequent cycle.

19. The method of claim 10, further comprising maintaining the sales valve open for a first time period after closing the bypass valve.

20. The method of claim 19, further comprising adjusting the first time period.

18. A method of optimizing an artificial lift well operating on a cycle, comprising:

opening a sales valve disposed on a delivery line for a gas flow;

closing a bypass valve disposed on a bypass line leading from the delivery line to the well;

measuring a first pressure differential across two points upstream from the sales valve on the delivery line;

comparing the first pressure differential to a first stored value;

closing the sales valve when the first pressure differential is less than or equal to the first stored value;

opening a bypass valve to deliver the gas flow to the well;

measuring a second pressure differential across the two points;

comparing the second pressure differential to a second stored value;

closing the bypass valve when the second pressure differential is at least the same as the second stored value;

opening the sales valve;

adjusting one or more of the stored values prior to beginning the subsequent cycle.

21. The method of claim 18, further comprising maintaining the bypass valve open for a first time period after closing the sales valve.

22. The method of claim 21, further comprising adjusting the first time period.

23. The method of claim 18, further comprising a compressor disposed downstream from the two points and upstream from the sales valve.

24. The method of claim 23, wherein the bypass line connects to the delivery line at a location between the compressor and the sales valve.

25. The method of claim 24, further comprising maintaining the sales valve open for a first time period after closing the bypass valve.

26. The method of claim 25, further comprising maintaining the bypass valve open for a second time period time after closing the sales valve.

27. The method of claim 26, further comprising adjusting the first time period.

28. A method of operating an artificial lift system, comprising:

measuring a first pressure at a first location in the system;

measuring a second pressure at a second location in the system;

calculating a first pressure differential between the first pressure and the second pressure;

comparing the first pressure differential to a first stored value;

opening a valve between a tubing and a delivery line when the first pressure differential is at least the same as the first stored value;

the valve permitting pressurized gas to flow from the tubing into the delivery line;

measuring a second pressure differential across two points in the delivery line;

comparing the second pressure differential to a second stored value;

closing the valve when the second pressure differential is less than or equal to the second stored value; and

adjusting one or more of the stored values prior to beginning the subsequent cycle.

29. The method of claim 28, further comprising detecting a closed contact switch.

30. The method of claim 29, wherein detecting a closed contact switch comprises detecting a plunger arrival.

31. The method of claim 29, wherein detecting a closed contact switch comprises detecting a decrease in a casing pressure.

32. The method of claim 28, wherein the closed contact switch is detected within a first time period.

33. The method of claim 32, wherein the closed contact switch is detected within a second time period if the close contact switch was not detected within the first time period.

34. The method of claim 33, wherein detecting the closed contact switch comprises detecting a plunger arrival.

35. The method of claim 34, wherein a vent valve is opened during the second time period.

36. The method of claim 28, wherein the first location is selected from the group consisting of a casing, the tubing, and the delivery line.

37. The method of claim 36, herein the second location is selected from the remaining locations in the group.

38. The method of claim 28 further comprising maintaining the valve open for a first time period after sensing the closed contact switch.

39. The method of claim 38, further comprising adjusting the first time period for which the valve is maintained open prior to beginning a subsequent cycle.

40. The method of claim 28, further comprising maintaining the valve closed for a first time period after closing the valve.

41. The method of claim 40, further comprising maintaining the valve open for a second time period after sensing the closed contact switch.

42. A computer readable medium containing instructions which, when executed, performs an operation for well production processes, the operation comprising:

measuring a first press re differential between a casing pressure and a sales line pressure;

comparing the first pressure differential to a first stored value;

opening a valve between a tubing and a sales line when the first pressure differential is at least the same as the first stored value, the valve permitting pressurized gas to flow from the tubing into the sales line;

detecting the arrival of plunger at a predetermined location in the tubing;

measuring a second pressure differential across two points in the sales line;

comparing the second pressure differential to a second stored value;

closing the valve when he second pressure differential is less than or equal to the second stored value; and

adjusting one or more of the stored values prior to beginning a subsequent cycle.

43. The computer readable medium of claim 42, further comprising maintaining the valve open for a first time period after detecting the arrival of the plunger.

44. The computer readable medium of claim 43, further comprising adjusting the first time period for which the valve is maintained open prior to beginning a subsequent cycle.

45. The computer readable medium of claim 42, further comprising maintaining the valve closed for a first time period after closing the valve.

46. The computer readable medium of claim 45, further comprising maintaining the valve open for a second time period after detecting the arrival of the plunger.

47. The computer readable medium of claim 42, wherein the arrival of the plunger is detected within a first time period.

48. The computer readable medium of claim 47, wherein the arrival of the plunger is detected within a second time period if the arrival of the plunger was not detected in the first time period.

49. The computer readable medium of claim 48, wherein adjusting one or more of the stored values comprises increasing the first stored value if the arrival of the plunger was not detected within the second time period.

50. The computer readable medium of claim 48, wherein adjusting one or more of the stored values comprises increasing the second stored value if the arrival of the plunger was not detected within the second time period.

51. An automated method of operating a well having an on time and an off time, comprising:

measuring a first press re differential between a casing pressure and a sales line pressure;

comparing the first pre sure differential;

opening a valve between a tubing and a sales line when the first pressure differential is at least the same as the first stored value, the valve permitting pressurized gas to flow from the tubing into the sales line;

sensing a completion a portion of the cycle;

maintaining the valve closed for a first time period after closing the valve;

maintaining the valve pen for a second time period after sensing the completion of a portion of the cycle;

measuring a second pressure differential;

comparing the second pressure differential to a second stored value;

closing the valve when the second pressure differential is less than or equal to the second stored value; and

adjusting one or more of the stored values.

52. A method of operating a well having an on time and an off time cycle, comprising:

measuring a first pressure differential;

comparing the first pressure differential to a first stored value;

opening a valve between a tubing and a sales line when the first pressure differential is at least the same as the first stored value, the valve permitting pressurized gas to flow from the tubing into the sales line;

measuring a second pressure differential;

comparing the second pressure differential to a second stored value;

closing the valve when the second pressure differential is less than or equal to the second stored value; and

adjusting one or more of the stored values when a completion of the cycle is detected.

53. The method of claim 52, wherein the first pressure differential is measured between a casing pressure and a sales line pressure.

54. The method of claim 52, wherein the second pressure differential is measured across two points in the sales line.

55. The method of claim 52, wherein the first stored value is adjusted prior to beginning a subsequent cycle.

56. The method of claim 52, wherein the second stored value is adjusted prior to beginning a subsequent cycle.

57. The method of claim 52, further comprising maintaining the valve open for a first time period.

58. The method of claim 57, further comprising adjusting the first time period for which the valve is maintained open.

59. The method of claim 52, further comprising maintaining the valve closed for a first time period after closing the valve.

60. The method of claim 59, further comprising adjusting the first time period for which the valve is closed.