Multi-stage blowout preventer for high-pressure deep well

Abstract

The invention discloses a high-pressure deep well multi-stage blowout preventer which is mainly composed of a first-stage blowout preventer assembly, a second-stage blowout preventer assembly, a second-stage blowout preventer assembly, a pressure balance system, an outer annulus blowout preventer assembly and a sealing connector. The two-stage blowout prevention system has the advantages that the two-stage blowout prevention system combines the cone-shaped valve core and the automatic closing and opening advantages of the butterfly valve, automatic double isolation of the fluid pressure of the lower stratum is achieved, and the two-stage blowout prevention system is simple in structure, convenient to operate and high in safety. Compared with an existing blowout prevention tool, the blowout prevention tool has the advantages that an electro-hydraulic valve is not arranged, the butterfly valve and the main valve element can be opened only through the pressure difference between well drilling working fluid and the formation, the structure is simple, machining and manufacturing are easy to achieve, cost is low, and maintenance is easy.

Description

Technical Field

[0001] The invention belongs to the technical field of high-pressure deep well downhole tools and relates to a high-pressure deep well multi-stage blowout preventer. Background Art

[0002] At present, the blowout prevention system of oil and gas fields includes external blowout prevention system and drill string internal blowout prevention system. Both at home and abroad, there are relatively mature products in large quantities in the field, whether it is the blowout preventer for the outer annulus of the wellbore or the tools of the blowout prevention system in the drill string. Among them, patent CN110005371B involves a fully electric-driven downhole blowout preventer. The electric system of the downhole blowout preventer is exposed to the harsh environment underground, with high requirements for structural layout and control, great difficulty in operation, and greatly reduced reliability, and it is impossible to meet the requirements for multi-level safety protection underground.

[0003] Regarding the underground internal and external integrated blowout preventer, in 1993, Norwegian scientists S. Sangesland, A. Sivertsen, etc., mentioned a lift valve type underground blowout preventer in their paper. The control method still adopted the underground automatic judgment method, but deformation occurred when the rubber cylinder was unsealed.

[0004] Therefore, it is necessary to improve the existing downhole blowout prevention tools, which have complex designs, high operating precision requirements, and low reliability. Summary of the invention

[0005] The purpose of the present invention is to provide a high-pressure deep well multi-stage blowout preventer, which can effectively improve the downhole pressure balance during the drilling process and has stable operation.

[0006] The technical solution adopted by the present invention is a high-pressure deep well multi-stage blowout preventer, which includes a first-stage blowout preventer assembly, a second-stage blowout preventer assembly, a third-stage blowout preventer assembly, a pressure balance system and an outer annulus blowout preventer assembly connected in sequence.

[0007] The present invention is also characterized in that:

[0008] The first-stage blowout preventer assembly includes a hollow sleeve-shaped upper shell, an intermediate connecting shell, and a positioning ring which are connected in sequence. The first connecting shell is coaxially arranged outside the upper shell, a cavity is arranged between the upper shell and the first connecting shell, a thrust cylinder is installed at the position of the cavity, and a sealing ring is installed on the outer wall of the thrust cylinder; a cylindrical piston is coaxially arranged inside the intermediate connecting shell, a spring installation cavity is arranged between the cylindrical piston and the intermediate connecting shell, a first spring is installed in the spring installation cavity, the end of the thrust cylinder is close to one end surface of the cylindrical piston, the positioning ring is located at the other end of the cylindrical piston, and a first butterfly valve is installed on the positioning ring through a first pin shaft.

[0009] The second-stage blowout preventer assembly includes a lower shell, one end of which is connected to the middle connecting shell, the other end of which is connected to the second connecting shell, a first valve core is provided at the connection between the lower shell and the second connecting shell, a wear-resistant alloy layer is provided at the contact portion between the first valve core and the lower shell, the second butterfly valve is fixed to the first valve core through a second pin shaft, and a second spring is installed on the first valve core.

[0010] The third-stage blowout preventer includes a third connecting shell, the third connecting shell and the second connecting shell, an outer sleeve is coaxially arranged inside the third connecting shell, a valve stem shell and a valve stem are coaxially arranged inside the outer sleeve in sequence, one end of the valve stem shell is connected to a lower positioning joint, a cavity is arranged in the middle of the lower positioning joint, a third spring is installed in the cavity, the second connecting shell is threadedly connected to the lower positioning joint, and the main valve core is installed at one end of the valve stem away from the lower positioning joint.

[0011] The pressure balancing system includes a balancing pressure hole and a cone valve core, both of which are arranged on the outer cylindrical end surface of the third connecting shell; a fourth spring is installed on the cone valve core, and a central connecting sleeve is also coaxially arranged at the center of the third connecting shell, one end of the central connecting sleeve is arranged close to the main valve core, and the other end of the central connecting sleeve is connected to a sealing joint.

[0012] The area of ​​the third connecting shell where the central connecting sleeve is located and the area where the sealing joint is located are both provided with high-pressure fluid channels.

[0013] The outer annulus blowout preventer assembly comprises a positioning pressure ring, a first rubber cylinder, a second rubber cylinder, a third rubber cylinder, a fourth rubber cylinder and a fifth rubber cylinder which are connected in sequence;

[0014] The positioning pressure ring is installed at the step end surface of the sealing joint, the main pressure ring is installed between the positioning pressure ring and the first rubber cylinder, the first spacer ring is installed between the first rubber cylinder and the second rubber cylinder, the second spacer ring is installed between the second rubber cylinder and the third rubber cylinder, the third spacer ring is installed between the third rubber cylinder and the fourth rubber cylinder, the fourth spacer ring is installed between the fourth rubber cylinder and the fifth rubber cylinder, the fifth rubber cylinder is tightly fitted on one end surface of the retaining ring, and the rubber cylinder seat is serially connected in the middle part of the sealing joint.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1. The present invention is designed with a three-stage blowout preventer assembly to achieve multi-stage protection. At the same time, with an external blowout preventer assembly, it can achieve the goal of rapid and stable internal and external blowout prevention under any pressure conditions. If the first stage fails, other parts can be supplemented in time.

[0017] 2. The present invention does not require electro-hydraulic valve control. Compared with previous blowout prevention tools, it does not require electro-hydraulic valve parts. The butterfly valve and the main valve core can be opened by simply using the pressure difference between the drilling fluid and the formation. The structure is simpler than that of previous electro-hydraulic blowout preventers, easy to manufacture, low cost, and easy to maintain.

[0018] 3. The present invention is designed with a pressure balance system, which does not require other auxiliary structures and can effectively utilize the pressure of the inner and outer annular fluids to automatically compress or reset the isolation rubber, thereby automatically adjusting the balance between the wellhead pressure and the bottom hole pressure.

[0019] 4. The secondary blowout prevention system of the invention combines the advantages of the valve core conical structure and the automatic closing and opening of the butterfly valve to achieve automatic double isolation of the lower formation fluid pressure, thereby preventing the high-pressure formation fluid from continuing to return. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a high-pressure deep well multi-stage blowout preventer of the present invention;

[0021] Figure 2 A schematic diagram of fluid movement during normal drilling of the high-pressure deep well multi-stage blowout preventer of the present invention;

[0022] Figure 3 It is a schematic diagram of the high-pressure deep well multi-stage blowout preventer of the present invention in an open state;

[0023] Figure 4 It is a schematic diagram of the closed state of the high-pressure deep well multi-stage blowout preventer of the present invention.

[0024] In the figure, 1. first-stage blowout preventer assembly, 2. second-stage blowout preventer assembly, 3. third-stage blowout preventer assembly, 4. pressure balance system, 5. outer annular blowout preventer assembly, 6. lower shell, 7. center connecting sleeve, 8. sealing joint, 9. well wall, 10. upper shell, 11. first connecting shell, 12. thrust cylinder, 13. first O-type sealing ring, 14. cylinder piston, 15. first spring, 16. intermediate connecting shell, 17. positioning ring, 18. first pin shaft, 19. first butterfly valve, 20. wear-resistant alloy layer, 21. second pin shaft, 22. first valve core, 23. second butterfly valve, 24. second spring, 25. second O-type sealing ring, 26. second connecting shell , 31. back cap, 32. center tube, 33. third connecting shell, 34. lower positioning joint, 35. third spring, 36. valve stem, 37. outer sleeve, 38. valve stem shell, 301. main valve core, 40. pressure balance hole, 41. second O-ring, 42. cone valve core, 43. fourth spring, 44. high-pressure fluid channel, 50. positioning pressure ring, 51. main pressure ring, 52. first rubber cylinder, 53. first spacer ring, 54. second rubber cylinder, 55. second spacer ring, 56. third rubber cylinder, 57. fourth rubber cylinder, 58. fourth spacer ring, 59. fifth rubber cylinder, 501. retaining ring, 502. rubber cylinder seat, 503. guide joint, 504. tail end positioning cylinder. DETAILED DESCRIPTION

[0025] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] The high-pressure deep well multi-stage blowout preventer of the present invention is as follows Figure 1 As shown, it mainly consists of a first-stage blowout preventer assembly 1, a second-stage blowout preventer assembly 2, a third-stage blowout preventer assembly 3, a pressure balance system 4, an outer annulus blowout preventer assembly 5, a lower shell 6, a central connecting sleeve 7, and a sealing joint 8.

[0027] The first-stage blowout preventer assembly 1 is mainly composed of an upper shell 10, a first connecting shell 11, a thrust cylinder 12, a first O-ring 13, a cylinder piston 14, a first spring 15, an intermediate connecting shell 16, a positioning ring 17, a first pin 18, and a first butterfly valve 19. The upper shell 10 is threadedly connected to the intermediate connecting shell 16, a cavity is arranged between the upper shell 10 and the first connecting shell 11, the thrust cylinder 12 is placed in the cavity, a sealing groove first O-ring 13 is arranged on the outer circumference of the thrust cylinder 12, and a plurality of first O-rings 13 are installed in the sealing grooves. The end of the thrust cylinder 12 is close to the left end surface of the cylinder piston 14, a spring installation cavity is arranged between the cylinder piston 14 and the intermediate connecting shell 16, the first spring 15 is installed in the cavity, the positioning ring 17 is installed at the step position at the right end of the intermediate connecting shell 16, the first butterfly valve 19 is fixed at the right end position of the positioning ring 17 by the first pin 18, and the intermediate connecting shell 16 is threadedly connected to the upper end of the lower shell 6.

[0028] The second-stage blowout preventer assembly is mainly composed of a wear-resistant alloy layer 20, a second pin shaft 21, a first valve core 22, a second butterfly valve 23, a second spring 24, a second O-type sealing ring 25, and a second connecting shell 26. The contact portion between the first valve core 22 and the lower shell 6 is provided with a wear-resistant alloy layer. The second butterfly valve 23 is fixed to the left end position of the inner hole of the first valve core 22 by the second pin shaft 21. The first valve core 22 is provided with a spring seat, and the second spring 24 is installed at the spring seat position. The second connecting shell 26 is provided with sealing grooves, and the second O-type sealing ring 25 is installed in these sealing grooves. The second connecting shell 26 is threadedly connected to the lower end of the lower shell 6.

[0029] The third-stage blowout preventer assembly is mainly composed of a back cap 31, a center pipe 32, a third connecting shell 33, a lower positioning joint 34, a third spring 35, a valve stem 36, an outer sleeve 37, a valve stem shell 38, and a main valve core 301. The back cap 31 is threadedly connected to the center pipe 32, the lower end of the second connecting shell 26 is threadedly connected to the upper end of the third connecting shell 33, a cavity is provided in the middle of the lower positioning joint 34, the third spring 35 is installed in the cavity, the valve stem 36 is installed in the center hole of the valve stem shell 38, the valve stem shell 38 is installed in 37 and the inner hole of the outer sleeve, the third connecting shell 33 is threadedly connected to the lower positioning joint 34, and the main valve core 301 is installed at the right end of the valve stem 36.

[0030] The pressure balancing system is mainly composed of a balancing pressure hole 40, a cone valve core 41, a second O-ring 42, a fourth spring 43, and a high-pressure fluid channel 44. The outer cylindrical end surface of the third connecting shell 33 is provided with a balancing pressure hole 40, and the outer cylindrical end surface of the third connecting shell 33 is provided with an opening groove of the cone valve core 41. The cone valve core 41 is installed in the opening groove, and the fourth spring 43 is installed at the lower end of the cone valve core 41. The third connecting shell 33 and the sealing joint 8 are also provided with a high-pressure fluid channel 44, and the high-pressure fluid channel 44 of the third connecting shell 33 and the sealing joint 8 are connected.

[0031] The outer annulus blowout preventer assembly is mainly composed of a positioning pressure ring 50, a main pressure ring 51, a first rubber cylinder 52, a first spacer ring 53, a second rubber cylinder 54, a second spacer ring 55, a third rubber cylinder 56, a fourth rubber cylinder 57, a fourth spacer ring 58, a fifth rubber cylinder 59, a retaining ring 501, a rubber cylinder seat 502, a guide joint 503, and a tail end positioning cylinder 504. The positioning pressure ring 50 is installed at the step end surface of the sealing joint 8, the main pressure ring 51 is installed in the middle position between the positioning pressure ring 50 and the first rubber cylinder 52, the first spacer ring 53 is installed between the first rubber cylinder 52 and the second rubber cylinder 54, the second spacer ring 55 is installed between the second rubber cylinder 54 and the third rubber cylinder 56, the third spacer ring 58 is installed between the third rubber cylinder 57 and the fourth rubber cylinder 59, the fourth spacer ring 58 is installed between the fourth rubber cylinder 57 and the fifth rubber cylinder 59, the fifth rubber cylinder 59 is tightly fitted on the left end surface of the retaining ring 501, the rubber cylinder seat 502 is connected in series in the middle part of the sealing joint 8, the guide joint 503 is embedded between the retaining ring 501 and the rubber cylinder seat 502 in a threaded connection manner, and the tail end positioning cylinder 504 is embedded in the annular groove of the retaining ring 501.

[0032] Figure 2-Figure 4 FIG. 1 is a schematic diagram of the working process of the high-pressure deep well multi-stage blowout preventer of the present invention, as shown in FIG. Figure 2 , Figure 3 As shown, the tool is lowered into the well. During normal drilling, the pressure of the drilling fluid pumped into the well from the wellhead is higher than the formation pressure. The drilling fluid enters the cavity of the upper shell 10 and the first connecting shell 11, pushing the thrust cylinder 12 and the cylinder piston 14 to move rightward. The cylinder piston 14 pushes the first butterfly valve 19 to rotate counterclockwise, so that the first butterfly valve 19 is in an open state. In addition, the pressure of the drilling fluid pumped into the well is higher than the formation pressure. The drilling fluid continues to move downward, and the second butterfly valve 23 can be quickly pushed open. The drilling fluid enters the lower chamber and finally reaches the drill bit position.

[0033] like Figure 3As shown, when the formation pressure is relatively large and slightly higher than the drilling fluid pressure, the formation fluid enters 301 and the main valve core position, and the formation high-pressure fluid will push the main valve core 301 and the valve stem 36 to move to the left until the main valve core 301 rests on the right end surface of the outer sleeve 37, so that the upper drilling fluid pressure and the returned formation fluid pressure are balanced, reaching a normal drilling state.

[0034] like Figure 4 As shown, when the formation pressure is relatively large, which is larger than the drilling working fluid pressure, a part of the formation fluid enters the main valve core 301 position, and the formation high-pressure fluid will push the main valve core 301 and the valve stem 36 to move to the left until the main valve core 301 rests on the right end surface of the outer sleeve 37, and the other part continues to return upward, passes through the second butterfly valve 23, and then pushes the second butterfly valve 23 and the first valve core 22 to move to the left, so that the second butterfly valve 23 and the first valve core 22 are closed.

[0035] like Figure 4 As shown, when the formation pressure is relatively large, much higher than the drilling fluid pressure, a part of the formation fluid closes the main valve core 301, the second butterfly valve 23 and the first valve core 22, while a part of the formation fluid continues to flow back upward and enters the cylindrical piston 14 and the thrust cylinder 12. Due to the pressure difference, the cylindrical piston 14 and the thrust cylinder 12 will move to the left, and the first butterfly valve 19 will rotate clockwise until the first butterfly valve 19 is in a vertical position, that is, a closed state.

[0036] like Figure 4 As shown, when the external pressure of the BOP system is too high, the high-pressure fluid pushes the cone valve core 41, so that the cone valve core 41 compresses the fourth spring 43 and moves downward, and the high-pressure fluid enters the outer annulus BOP assembly 5 through the high-pressure fluid channel 44, pushing and positioning the pressure ring 50, the main pressure ring 51, the rubber tube and the spacer ring to move downward, and the rubber tube is compressed axially and expanded laterally and then closely attached to the well wall 9, isolating the outer annulus flow channel, so that the high-pressure formation fluid in the outer annulus cannot return, and plays a role in the safety protection of the outer annulus. Similarly, the high-pressure fluid in the outer annulus can reach the position of the cone valve core 41 through the balanced pressure hole 40, and can also cause the rubber tube to expand and isolate the outer annulus.

[0037] Example 1

[0038] A high-pressure deep well multi-stage blowout preventer comprises a first-stage blowout preventer assembly 1, a second-stage blowout preventer assembly 2, a third-stage blowout preventer assembly 3, a pressure balance system 4 and an outer annulus blowout preventer assembly 5 which are connected in sequence.

[0039] Example 2

[0040] On the basis of Example 1, the first-stage blowout preventer assembly 1 includes a hollow sleeve-shaped upper shell 10, an intermediate connecting shell 16, and a positioning ring 17 connected in sequence. The first connecting shell 11 is coaxially arranged on the outside of the upper shell 10, and a cavity is arranged between the upper shell 10 and the first connecting shell 11. The thrust cylinder 12 is installed at the position of the cavity, and a sealing ring 13 is installed on the outer wall of the thrust cylinder 12; a cylindrical piston 14 is coaxially arranged inside the intermediate connecting shell 16, and a spring installation cavity is arranged between the cylindrical piston 14 and the intermediate connecting shell 16. A first spring 15 is installed in the spring installation cavity. The end of the thrust cylinder 12 is close to the end surface of one end of the cylindrical piston 14, and the positioning ring 17 is located at the other end of the cylindrical piston 14. A first butterfly valve 19 is installed on the positioning ring 17 through a first pin 18.

[0041] Example 3

[0042] On the basis of Example 2, the second-stage blowout preventer assembly includes a lower shell 6, one end of the lower shell 6 is connected to the intermediate connecting shell 16, the other end of the lower shell 6 is connected to the second connecting shell 26, a first valve core 22 is provided at the connection between the lower shell 6 and the second connecting shell 26, a wear-resistant alloy layer 20 is provided at the contact portion between the first valve core 22 and the lower shell 6, a second butterfly valve 23 is fixed to the first valve core 22 by a second pin shaft 21, and a second spring 24 is installed on the first valve core 22.

[0043] Example 4

[0044] On the basis of Example 3, the third-stage blowout preventer includes a third connecting shell 33, the third connecting shell 33 and the second connecting shell 26, an outer sleeve 37 is coaxially arranged inside the third connecting shell 33, a valve stem shell 38 and a valve stem 36 are coaxially arranged inside the outer sleeve 37 in sequence, one end of the valve stem shell 38 is connected to a lower positioning joint 34, a cavity is arranged in the middle of the lower positioning joint 34, a third spring 35 is installed in the cavity, the second connecting shell 33 is threadedly connected to the lower positioning joint 34, and the main valve core 301 is installed at one end of the valve stem 36 away from the lower positioning joint 34.

Claims

1. High-pressure deep well multi-stage blowout preventer, characterized by: The invention comprises a first-stage blowout preventer assembly (1), a second-stage blowout preventer assembly (2), a third-stage blowout preventer assembly (3), a pressure balance system (4) and an outer annulus blowout preventer assembly (5) which are connected in sequence.

2. The high-pressure deep well multi-stage blowout preventer according to claim 1 is characterized in that: The first-stage blowout preventer assembly (1) comprises a hollow sleeve-shaped upper shell (10), an intermediate connecting shell (16), and a positioning ring (17) which are connected in sequence. The upper shell (10) is coaxially provided with a first connecting shell (11), a cavity is provided between the upper shell (10) and the first connecting shell (11), a thrust cylinder (12) is installed at the position of the cavity, and a sealing ring (13) is installed on the outer wall of the thrust cylinder (12); a cylindrical piston (14) is coaxially provided inside the intermediate connecting shell (16), a spring installation cavity is provided between the cylindrical piston (14) and the intermediate connecting shell (16), a first spring (15) is installed in the spring installation cavity, the end of the thrust cylinder (12) is closely attached to one end surface of the cylindrical piston (14), the positioning ring (17) is located at the other end of the cylindrical piston (14), and a first butterfly valve (19) is installed on the positioning ring (17) via a first pin (18).

3. The high-pressure deep well multi-stage blowout preventer according to claim 2 is characterized in that: The second-stage blowout preventer assembly comprises a lower housing (6), one end of the lower housing (6) is connected to an intermediate connecting housing (16), the other end of the lower housing (6) is connected to a second connecting housing (26), a first valve core (22) is provided at the connection between the lower housing (6) and the second connecting housing (26), a wear-resistant alloy layer (20) is provided at the contact portion between the first valve core (22) and the lower housing (6), a second butterfly valve (23) is fixed to the first valve core (22) via a second pin shaft (21), and a second spring (24) is installed on the first valve core (22).

4. The high-pressure deep well multi-stage blowout preventer according to claim 3 is characterized in that: The third-stage blowout preventer comprises a third connecting shell (33), the third connecting shell (33) and the second connecting shell (26), an outer sleeve (37) is coaxially arranged inside the third connecting shell (33), a valve stem shell (38) and a valve stem (36) are coaxially arranged inside the outer sleeve (37), one end of the valve stem shell (38) is connected to a lower positioning joint (34), a cavity is arranged in the middle of the lower positioning joint (34), a third spring (35) is installed in the cavity, the second connecting shell (33) is threadedly connected to the lower positioning joint (34), and the main valve core (301) is installed at one end of the valve stem (36) away from the lower positioning joint (34).

5. The high-pressure deep well multi-stage blowout preventer according to claim 4 is characterized in that: The pressure balancing system (4) comprises a balancing pressure hole (40) and a cone valve core (41), both of which are arranged on the outer cylindrical end surface of the third connecting shell (33); a fourth spring (43) is installed on the cone valve core (41), and a central connecting sleeve (7) is coaxially arranged at the center of the third connecting shell (33), one end of the central connecting sleeve (7) is arranged close to the main valve core (301), and the other end of the central connecting sleeve (7) is connected to a sealing joint (8).

6. The high-pressure deep well multi-stage blowout preventer according to claim 5 is characterized in that: The area of ​​the third connection housing (33) where the central connection sleeve (7) is located and the area where the sealing joint (8) is located are both provided with a high-pressure fluid channel (44).

7. The high-pressure deep well multi-stage blowout preventer according to claim 6 is characterized in that: The outer annular blowout preventer assembly (5) comprises a positioning pressure ring (50), a first rubber cylinder (52), a second rubber cylinder (54), a third rubber cylinder (56), a fourth rubber cylinder (57) and a fifth rubber cylinder (59) which are connected in sequence; The positioning pressure ring (50) is installed at the step end surface of the sealing joint (8), the main pressure ring (51) is installed between the positioning pressure ring (50) and the first rubber cylinder (52), the first spacer ring (53) is installed between the first rubber cylinder (52) and the second rubber cylinder (54), the second spacer ring (55) is installed between the second rubber cylinder (54) and the third rubber cylinder (56), the third spacer ring (58) is installed between the third rubber cylinder (57) and the fourth rubber cylinder (59), the fourth spacer ring (58) is installed between the fourth rubber cylinder (57) and the fifth rubber cylinder (59), the fifth rubber cylinder (59) is tightly fitted on one end surface of the retaining ring (501), and the rubber cylinder seat (502) is connected in series to the middle part of the sealing joint (8).

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