RU2811358C1 - Method for drilling and repairing wells with low formation pressures and device for its implementation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention can be used when drilling and repairing wells with abnormally low formation pressure (ALFP). A drill string with a working tool is lowered into the well, into which a device is installed between the upper and the lower parts, including a jet pump and a self-sealing cup-type packer element, configured to rotate relative to the axis of the device to ensure tightness during operation of the device and dividing the annulus of the well into the upper and the lower annulus. An active fluid flow is supplied through the upper part of the drill string into a device in which the active fluid flow is divided into two parts. One part of the flow is directed into the lower annulus of the well to circulate fluid in the near-wellbore zone. The other part of the flow is directed to a jet pump, which lifts the passive medium along the bottom of the drill string from the bottom-hole zone and directs it to the upper annulus of the well for removal to the surface. The bottom is cleaned by moving the drill string down, drilled and milled by rotating the drill string with the working tool while simultaneously moving down or up.

EFFECT: loss of drilling fluid is minimized when carrying out work in wells with ALFP.

4 cl, 10 dwg

Description

The group of inventions relates to the field of oil and gas industry and can be used for routine and major repairs of oil and gas wells with abnormally low reservoir pressures (ANPR), including inclined and horizontal ones, for drilling, milling of hydraulic fracturing (HF) ports and multi-stage hydraulic fracturing ports (MSHF), removing sand and sludge deposits using a device lowered as part of a drill string or tubing.

The inventive device and the method of its use make it possible to add the required number of drilling or tubing pipes to carry out work in horizontal lateral wellbores and transmit rotation to the working tool.

A device for cleaning a well from a sand plug is known (see RF patent No. 2298643, MPK E21B 37/00, published on May 10, 2007), consisting of a pipe concentrically installed in the hollow body of a hollow cylindrical nozzle installed at the lower end of the hollow body, bends , connecting the internal space of the pipe plugged from below with the zone of sand plug formation, a self-sealing collar, a clamping nut installed at the upper end of the hollow body and a limiter rigidly connected to the hollow body.

The disadvantages of this device are:

- the device cannot be used for milling ports after hydraulic fracturing and multi-stage hydraulic fracturing;

- the device can only be used until the boundary of the absorbent formation is reached;

- the device must be located directly at the border of the sand plug.

A pump-vacuum device for cleaning a well from a sand plug using coiled tubing pipes under conditions of abnormally low reservoir pressures is also known (see RF patent No. 2314411, IPC E21B 37/00, published 01/10/2008), consisting of a jet pump, an isolation unit , including a branch pipe coaxially installed in the housing to form a suction annular channel, upper and lower packing elements located on the housing, and a destruction unit.

The disadvantages of this device are:

- use of coiled tubing pipes, which have a limited resource and high cost

- the device cannot be used for milling hydraulic fracturing and multi-stage hydraulic fracturing ports.

The closest to the claimed technical solution in terms of technical essence and achieved technical result is a jet apparatus for flushing wells (Patent for invention 2139422 Sultanov B.Z., Vagapov S.Yu., Khusni Kh.M. application submission: 1997-06-10 publication patent: 10.10.1999). A jet apparatus for flushing wells contains a housing with a jet pump installed in it, including a nozzle and a diffuser with a displacement chamber. The housing contains channels for supplying active and passive media. A sealing packer is installed on the body, including a barrel, cylinder, piston and collar. The barrel contains a pipe rigidly connected to the body, the internal cavity of which forms a channel for supplying a passive medium. The annular cavity formed by the outer surface of the nozzle and the internal cavity of the barrel is equipped with a plug to isolate it from the suction area, and forms a channel for supplying the active medium to the lower end of the piston. During operation of the installation, the active medium acts on the piston, causing the suction zone to be isolated from the discharge zone. At the same time, the joint operation of a jet pump with a sealing packer makes it possible to increase the reliability of isolation of the annulus.

The disadvantages of this device are:

- due to the immobility of the sealing collars, there is no possibility of transmitting rotation to the tool;

- the diffuser channel is directed in the opposite direction from the direction of movement towards the mouth of the drilling fluid flow, particles may precipitate and create an emergency situation;

- the ability to install only one nozzle and diffuser in the jet pump;

- there is no compensation for the outflow of fluid from the working area, it is possible to cause gas, oil and water ingress from the formation;

- when increasing the drill string, a drop in pressure occurs, the packing elements return to the non-working position, the drilling fluid from the annulus freely penetrates into the productive formation, as a result, significant time is required to initiate circulation.

The listed disadvantages do not allow this device to be used effectively.

The claimed group of inventions is aimed at providing the possibility of drilling, drilling out hydraulic fracturing and multi-stage hydraulic fracturing ports, removing sand and sludge deposits in horizontal sidetracks in oil and gas wells with ANPD.

The technical result of the claimed inventions is to minimize the loss of drilling fluid when carrying out work in oil and gas wells with ANPD.

This technical result is achieved thanks to a method for drilling and repairing wells with low reservoir pressures, which consists in lowering a drill string into the well, into which a device is installed between the upper and lower parts, including a jet pump with a packer element, dividing the annulus of the well into upper and lower parts. lower annulus, feeds an active fluid flow through the upper part of the drill string into a device in which the active fluid flow is divided into two parts, one part of the flow is sent to the lower annulus of the well for fluid circulation in the work area, the other part of the flow is sent to a jet pump , a jet pump lifts the passive medium along the bottom of the drill string from the work area and directs it to the upper annulus of the well for removal to the surface, cleans the bottom by moving the drill string down, drills and mills by rotating the drill string with simultaneous movement down or up .

A device for implementing the method, containing a jet pump and at least one self-sealing cup-type packing element, configured to rotate relative to the axis of the device to ensure tightness during operation of the device, having a channel for supplying an active flow, running along the axis of the device, starting at the top connecting part of the device and ending in the dividing cavity in the device, with which the jet pump nozzle and the bypass channel communicate, made in the device to divert part of the active flow into the lower annulus, bypassing the self-sealing packer element, which is a separate cavity starting in the dividing cavity, passing further along the axis of the device under the self-sealing packing element and ending with an exit to the surface of the device below the self-sealing packing element, formed by connecting holes, channels, cavities made in the parts of the device, a channel for draining the passive medium, made along the axis of the lower part of the device, starting at the bottom connecting parts of the device and ending in the chamber of the jet pump, while the outlet from the expanding pipe of the jet pump to the surface of the device is located above the self-sealing packing element.

The device may include centering blocks designed to rotate relative to the axis of the device.

The invention is illustrated by drawings:

in fig. 1 shows a general diagram of the device in a longitudinal section;

in fig. Fig. 2 shows a general diagram of the device in section along line AA (see Fig. 1);

in fig. 3 shows a general diagram of the position of the device in the well during work;

in fig. Figure 4 shows a diagram of the operation of the device, a longitudinal section;

in fig. Figure 5 shows a diagram of the operation of the device, a cross section along the line BB (see Fig. 4);

in fig. 6-10 shows an example of the implementation of the device design; Fig. 6 shows a longitudinal section; FIG. 7-10 show cross-sections along lines B-B, D-G, D-D and E-E (see Fig. 6), respectively.

Positions in the drawings indicate:

1. body;

2. active flow supply channel;

3. dividing cavity;

4. nozzle;

5. camera;

6. expanding pipe;

7. passive medium removal channel;

8. cup-type self-sealing packer element;

9. bypass channel;

10. lower outlet;

11. upper outlet;

12. well;

13. lower part of the drill string;

14. work area;

15. working tool;

16. claimed device;

17. operating range;

18. shank suspension;

19. upper part of the drill string;

20. active thread;

21. one part of the active thread;

22. another part of the active thread;

23. upper annulus;

24. movement of the passive medium;

25. lower annulus;

26. drive;

27. upper centering block;

28. lower centering block;

29. coupling;

30. coupling passage channel;

31. pump housing;

32. passage channel of the pump housing;

33. longitudinal holes of the pump housing;

34. separator;

35. central chamber;

36. separator holes;

37. passage holes;

38. clip;

39. passage channel of the holder;

40. threaded holes;

41. throttle;

42. cavity;

43. distribution coupling;

44. passage channel of the distribution coupling;

45. longitudinal holes of the distribution coupling;

46. membrane body;

47. emergency membrane;

48. trunk;

49. bore passage;

50. longitudinal grooves;

51. cover;

52. cover cavity;

53. mandrel;

54. O-rings;

55. packer element cage;

56. bushing;

57. washer;

58. groove;

59. radial holes;

60. sub;

61. passage channel of the sub.

In the housing 1 there is a channel 2 for supplying the active flow, starting in the upper connecting (to the drill string) part of the housing 1 and ending in the dividing cavity 3 of the housing 1 (Fig. 1, 2). In housing 1 there is a jet pump consisting of a nozzle 4, a chamber 5 and an expanding pipe 6. The nozzle 4 communicates with the dividing cavity 3. In the housing 1 there is a channel 7 for removing the passive medium, starting in the lower connecting (to the drill string) part of the housing 1 and ending in chamber 5. Channel 2 and channel 7 do not intersect. On the body 1 there is at least one self-sealing cup-type packing element 8, configured to rotate relative to the axis of the device to ensure tightness during operation of the device. The cup-type self-sealing packer element 8 is positioned to withstand the pressure of the liquid column above the device. In the housing 1 there is a bypass channel 9, starting in the dividing cavity 3, passing under the self-sealing packer element 8 and ending with a lower outlet 10 on the surface of the housing 1 below the self-sealing packer element 8. The upper outlet 11 from the expanding pipe 7 on the surface of the housing 1 is located above self-sealing cup-type packing element 8.

The lower part 13 of the drill string is lowered into the well 12 (Fig. 3, 4, 5) using a well workover machine (WWM) or a drilling rig, with the length necessary to reach the work area 14 with a working tool 15 (mill, funnel, pen, etc. .d.), installed at its end with such a condition that the inventive device 16 does not reach the suspension of the liner 18 throughout the entire operating range 17. Then the inventive device 16 is fixed to the lower part 13 of the drill string, the upper part 19 of the drill string is built up above it, continue descent Upon reaching the work zone 14, an active flow 20 (drilling fluid) is supplied to the upper part 19 of the drill string. Having passed through channel 2, the active flow 20 enters the dividing cavity 3. From the dividing cavity 3, one part 21 of the active flow 20 is directed into the nozzle 4 of the jet pump, the other part 22 is sent into the bypass channel 9. The flow 21, leaving the nozzle 4, enters the expanding pipe 6 of the jet pump, creating a vacuum in the chamber 5 of the jet pump, and exits through the upper outlet 11 into the upper annular space 23 above the inventive device 16. The vacuum in the chamber 5 causes the movement of the passive medium 24 from the work area 14 of the well 12 along the lower part 13 of the drill string, then through channel 7 the passive medium 24 enters the chamber 5 of the jet pump and through the expanding pipe 6 of the jet pump, together with the flow 21, is carried into the upper annulus 23, through which it rises to the surface. The self-sealing packer element 8 does not allow the liquid to go back into the absorbent formation. The flow 22, leaving the inventive device 16 into the lower annulus 25 through the lower outlet 10, serves to ensure fluid circulation in the work area 14. The upper part 19 of the drill string is transmitted rotation from the drive 26 located on the surface. Through the inventive device 16 and the lower part 13 of the drill string, rotation is transmitted to the working tool 15. The self-sealing packer element 8 does not participate in the rotation of the drill string, providing a hermetically sealed separation of the annulus. Due to the design of the device, the well is simultaneously flushed, rotated and lowered to the required depth. If necessary, the upper part 19 of the drill string is increased. Technological operations continue. When the required depth is reached, a complete flush is carried out. Raise the drill string completely.

In fig. 6-10 provides an example of the implementation of a preferred device design. The proposed design contains two self-sealing packing elements 8, upper 27 and lower 28 centering blocks, and has the ability to install from one to three nozzles 4 and expanding pipes 6, while unused holes are plugged.

The device contains a coupling 29 with a coupling passage channel 30, at the lower end of which there are installed expanding pipes 6, located evenly around a circle concentric to the axis of the device. In the coupling 29 from the expanding pipes 6 there are upper outlet openings 11 directed upward to drain the passive medium. At the top of the coupling 29 there is a thread for attaching the device to the upper part 19 of the drill string. A pump housing 31 with a passage channel 32 of the pump housing and longitudinal holes 33 of the pump housing, located evenly around a circle concentric with the axis of the device, and forming the beginning of the bypass channel 9 of the device, are screwed onto the lower part of the coupling 29. In the pump housing 31 there is a separator 34 with a central chamber 35 and separator holes 36 radially extending from it. The holes 36 of the separator communicate with the dividing cavity 3 formed by the pump housing 31 and the separator 34. The separator 34 has nozzles 4 located evenly around a circle concentric with the axis of the device. The holes 36 of the separator communicate with the nozzles 4 and, through the cavity 3, with the holes 33 of the pump housing. In the separator 34 between the nozzles 4 there are passage holes 37 for the passage of the passive medium. Between the separator 34 and the coupling 29 in the pump housing 31 there is a holder 38 with a holder passage channel 39 for the active medium. The holder 38 forms the chamber 5. The holes 37 open into the chamber 5. The holder 38 ensures that the axes of the nozzles 4 and the expanding pipes 6 coincide. The holes 33 open into the threaded holes 40 into which the chokes 41 are screwed. The holes of the chokes 41 open into the cavity 42 between the housing 31 and a distribution coupling 43 screwed onto it. The openings of the throttles 41 communicate with the passage channel 44 of the distribution coupling and the longitudinal holes 45 of the distribution coupling, located evenly around a circle concentric with the axis of the device. The holes 45 communicate with the cavity 42. In the distribution coupling 43 there is a membrane housing 46 with an emergency membrane 47 installed in it, when triggered, a communication opens between the central channel 44 and the upper annulus 23 for the emergence of liquid circulation and the possibility of washing the upper annulus 23.

A barrel 48 is screwed into the distribution coupling 43 from below, having a barrel passage channel 49 and longitudinal grooves 50 evenly spaced on its surface. A cover 51 is screwed onto the distribution coupling 43, through which the barrel 48 passes. The cover 51 and the distribution coupling 43 form the cavity 52 of the cover. Holes 45 and grooves 50 communicate with the cavity 52. An upper centering block 27 is placed on the cover 51, freely rotating on the cover 51. Below on the barrel 48 there is a mandrel 53 freely rotating on it, sealed with rings 54 along the surface of contact with the cover 51. On the mandrel 53 self-sealing cup-shaped packing elements 8 are put on with packing element clips 55, separated by a sleeve 56. A lower centering block 28 is screwed onto the lower part of the mandrel 53, freely rotating on the barrel 48 together with the mandrel 53. Below is a washer 57 with a groove 58 and radial holes communicating with it 59. Grooves 50 on the barrel 48 communicate with the groove 58. A threaded sub 60 is screwed onto the barrel 48 from below for attaching the lower part 13 of the drill string to the device. The sub has a passage channel of 61 subs.

In this example implementation, active flow supply channel 2 is formed by holes 30, 39, 35, 36, passive medium outlet channel 7 is formed by holes 37, 32, 44, 49, 61, bypass channel 9 is formed by holes, cavities and grooves 33, 40, 42 , 45, 54, 50, 58, 59 and throttle 41. Housing 1 is formed by parts, except for parts of positions 8, 27, 28.

As used herein, the term “jet pump” means a device that has a nozzle, a chamber and an expansion joint that transfers energy from the working fluid to the produced fluid to artificially lift and remove the produced fluid from the well, while reducing the hydrostatic pressure of the column the combined fluid in the drill string or tubing string below the jet pump.

The term “channel” used in the description of the claimed invention means a cavity in the device formed by connecting holes and cavities made in the parts of the device, intended to form the direction of a separate fluid flow.

As used in the description of the claimed invention, the term “active fluid flow” means a fluid flow supplied through the drill string under pressure from the surface to the device.

The term “passive medium” used in the description of the claimed invention means a fluid flow lifted by the device along the drill string from the place of work in the well and carried to the surface.

Claims (4)

1. A method for drilling and repairing wells with low reservoir pressures, which consists in lowering a drill string with a working tool into the well, into which a device is installed between the upper and lower parts, including a jet pump and a self-sealing cup-type packer element, designed to rotate relative to the axis of the device, ensuring tightness during operation of the device and separating the annular space of the well into the upper and lower annular spaces, an active fluid flow is supplied through the upper part of the drill string into a device in which the active fluid flow is divided into two parts, one part of the flow is directed to the lower annular well space for fluid circulation in the near-wellbore zone, the other part of the flow is directed to a jet pump, which lifts the passive medium along the bottom of the drill string from the near-wellbore zone and directs it to the upper annulus of the well for removal to the surface, cleans the bottom by moving the drill string down, drilled and milled by rotating the drill string with the working tool while simultaneously moving down or up. 2. A device for implementing the method according to claim 1, including a channel for supplying an active flow, running along the axis of the device, starting in the upper connecting part of the device and ending in the dividing cavity in the device, with which the nozzle of the jet pump communicates and a bypass channel made for diversion part of the active flow into the lower annulus, bypassing the self-sealing cup-type packer element, which is a separate cavity starting in the dividing cavity, passing further along the axis of the device under the self-sealing cup-type packer element, ending with exit to the outer surface of the device below the self-sealing cup-type packer element in the lower annular space and formed by connecting holes, channels, cavities made in the device, a channel for draining the passive medium, made along the axis of the device, starting at the lower connecting part of the device and ending in the chamber of the jet pump, with the outlet from the expansion pipe of the jet pump to the surface device into the upper annulus is located above the self-sealing cup-type packer element. 3. The device according to claim 2, characterized in that it contains an additional self-sealing cup-type packer element. 4. The device according to claim 2, characterized in that it additionally contains centering blocks configured to rotate relative to the axis of the device.