High-pressure deep well multi-stage blowout preventer

Abstract

This invention discloses a high-pressure deep well multi-stage blowout preventer (BOP), mainly composed of a first-stage BOP assembly, a second-stage BOP assembly, a pressure balancing system, an outer annular BOP assembly, and a sealing joint. The pressure balancing system of this invention requires no other auxiliary structures and effectively utilizes the fluid pressure of the inner and outer annular spaces to automatically compress or reset the sealing rubber, thus automatically adjusting the balance between wellhead and bottomhole pressures. The second-stage BOP system combines the advantages of a conical valve core and the automatic closing and opening of a butterfly valve to achieve automatic dual isolation of the lower formation fluid pressure, preventing the high-pressure formation fluid from continuing to rise. Compared to previous BOP tools, this invention does not use electro-hydraulic valves; it only utilizes the pressure difference between the drilling fluid and the formation to open the butterfly valve and the main valve core. It has a simple structure, is easy to manufacture, has low cost, and is easy to maintain.

Description

Technical Field

[0001] This invention belongs to the field of high-pressure deep well downhole tool technology, and relates to a high-pressure deep well multi-stage blowout preventer. Background Technology

[0002] Currently, oil and gas field blowout preventer (BOP) systems include external BOP systems and drill string BOP systems. Both domestically and internationally, mature products are widely used in the field for both external annular BOPs and drill string BOP tools. Among them, patent CN110005371B relates to a fully electrically driven downhole BOP. The electric system of the downhole BOP is exposed to the harsh downhole environment, requiring sophisticated structural layout and control, resulting in high operational difficulty, significantly reduced reliability, and an inability to meet the multi-level safety protection requirements of downhole systems.

[0003] Regarding integrated downhole blowout preventers (BOPs), in 1993, Norwegian scientists S. Sangesland and A. Sivertsen, among others, published a paper mentioning a lift valve type downhole BOP. The control method described was still an automatic downhole detection system, but deformation occurred during the unsealing of the rubber sleeve.

[0004] Therefore, it is necessary to improve existing downhole blowout preventer tools, which are characterized by complex design, high operational precision requirements, and low reliability. Summary of the Invention

[0005] The purpose of this invention is to provide a high-pressure deep well multi-stage blowout preventer that can effectively improve downhole pressure balance during drilling and ensure stable operation.

[0006] The technical solution adopted in this invention is a high-pressure deep well multi-stage blowout preventer, comprising a first-stage blowout preventer assembly, a second-stage blowout preventer assembly, a third-stage blowout preventer assembly, a pressure balancing system, and an outer annular blowout preventer assembly connected in sequence.

[0007] The invention is further characterized by:

[0008] The first-stage blowout preventer assembly includes a hollow, sleeve-shaped upper housing, an intermediate connecting housing, and a positioning ring connected in sequence. A first connecting housing is coaxially disposed outside the upper housing, and a cavity is provided between the upper housing and the first connecting housing. A thrust cylinder is installed in the cavity, and a sealing ring is installed on the outer wall of the thrust cylinder. A cylindrical piston is coaxially disposed inside the intermediate connecting housing, and a spring mounting cavity is provided between the cylindrical piston and the intermediate connecting housing. A first spring is installed in the spring mounting cavity. The end of the thrust cylinder is close to one end face of the cylindrical piston, and the positioning ring is located at the other end of the cylindrical piston. A first butterfly valve is installed on the positioning ring via a first pin.

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

[0010] The third-stage blowout preventer includes a third connecting housing, which is coaxially connected to a second connecting housing. An outer sleeve is coaxially arranged inside the third connecting housing. Inside the outer sleeve, a valve stem housing and a valve stem are coaxially arranged in sequence. One end of the valve stem housing is connected to a lower positioning joint. A cavity is provided in the middle of the lower positioning joint. A third spring is installed in this cavity. The second connecting housing is threadedly connected to the lower positioning joint. The main valve core is installed at the 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 located on the outer circular end face of the third connecting housing. A fourth spring is installed on the cone valve core. A central connecting sleeve is also coaxially arranged at the center of the third connecting housing. One end of the central connecting sleeve is located close to the main valve core, and the other end of the central connecting sleeve is connected to a sealing joint.

[0012] High-pressure fluid channels are provided in both the area of ​​the third connecting housing where the central connecting sleeve is located and the area where the sealing joint is located.

[0013] The outer ring blowout preventer assembly includes a positioning pressure ring, a first rubber sleeve, a second rubber sleeve, a third rubber sleeve, a fourth rubber sleeve, and a fifth rubber sleeve connected in sequence;

[0014] The positioning pressure ring is installed on the stepped end face of the sealing joint. The main pressure ring is installed between the positioning pressure ring and the first rubber sleeve. The first spacer ring is installed between the first rubber sleeve and the second rubber sleeve. The second spacer ring is installed between the second rubber sleeve and the third rubber sleeve. The third spacer ring is installed between the third rubber sleeve and the fourth rubber sleeve. The fourth spacer ring is installed between the fourth rubber sleeve and the fifth rubber sleeve. The fifth rubber sleeve is tightly fitted to one end face of the retaining ring. The rubber sleeve seat is connected in series in the middle part of the sealing joint.

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

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

[0017] 2. This invention does not require electro-hydraulic valve control. Compared with previous blowout preventers, it does not require electro-hydraulic valve components. It can open the butterfly valve and the main valve core simply by using the drilling working fluid and the formation pressure difference. The structure is simpler than that of previous electro-hydraulic blowout preventers, which is easier to process and manufacture, has lower cost, and is easier to maintain.

[0018] 3. The present invention is designed with a pressure balancing system, which does not require other auxiliary structures. It can effectively utilize the fluid pressure of the inner and outer annulus to make the sealing rubber automatically compressed or reset, and can automatically adjust the balance between wellhead pressure and bottom hole pressure.

[0019] 4. The two-stage blowout preventer system of this invention combines the advantages of the valve core conical structure and the automatic closing and opening of the butterfly valve to achieve automatic dual isolation of the pressure of the lower formation fluid, thus preventing the high-pressure formation fluid from continuing to rise. Attached Figure Description

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

[0021] Figure 2 This is 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 This is a schematic diagram showing the open state of the high-pressure deep well multi-stage blowout preventer of the present invention;

[0023] Figure 4 This 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 diagram, 1. First-stage BOP assembly, 2. Second-stage BOP assembly, 3. Third-stage BOP assembly, 4. Pressure balancing system, 5. Outer annular BOP assembly, 6. Lower housing, 7. Center connecting sleeve, 8. Sealing joint, 9. Wellbore, 10. Upper housing, 11. First connecting housing, 12. Thrust cylinder, 13. First O-ring seal, 14. Cylindrical piston, 15. First spring, 16. Intermediate connecting housing, 17. Positioning ring, 18. First pin, 19. First butterfly valve, 20. Wear-resistant alloy layer, 21. Second pin, 22. First valve core, 23. Second butterfly valve, 24. Second spring, 25. Second O-ring seal, 26. Second connecting housing 31. Back cap, 32. Central tube, 33. Third connecting housing, 34. Lower positioning joint, 35. Third spring, 36. Valve stem, 37. Outer sleeve, 38. Valve stem housing, 301. Main valve core, 40. Pressure balance hole, 41. Second O-ring seal, 42. Cone valve core, 43. Fourth spring, 44. High-pressure fluid channel, 50. Positioning pressure ring, 51. Main pressure ring, 52. First rubber sleeve, 53. First spacer ring, 54. Second rubber sleeve, 55. Second spacer ring, 56. Third rubber sleeve, 57. Fourth rubber sleeve, 58. Fourth spacer ring, 59. Fifth rubber sleeve, 501. Retaining ring, 502. Rubber sleeve seat, 503. Guide joint, 504. Tail end positioning cylinder. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0026] This invention relates to a high-pressure deep well multi-stage blowout preventer, such as... 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 balancing system 4, an outer annular blowout preventer assembly 5, a lower housing 6, a central connecting sleeve 7, and a sealing joint 8.

[0027] The first-stage blowout preventer assembly 1 mainly consists of an upper housing 10, a first connecting housing 11, a thrust cylinder 12, a first O-ring seal 13, a cylindrical piston 14, a first spring 15, an intermediate connecting housing 16, a positioning ring 17, a first pin 18, and a first butterfly valve 19. The upper housing 10 and the intermediate connecting housing 16 are threaded together. A cavity is provided between the upper housing 10 and the first connecting housing 11, and the thrust cylinder 12 is placed in this cavity. A sealing groove for the first O-ring seal 13 is provided on the outer circumference of the thrust cylinder 12, and multiple first O-ring seals 13 are installed in these sealing grooves. The end of the thrust cylinder 12 is close to the left end face of the cylindrical piston 14. A spring mounting cavity is provided between the cylindrical piston 14 and the intermediate connecting housing 16, and the first spring 15 is installed in this cavity. The positioning ring 17 is installed at the right end step of the intermediate connecting housing 16. The first butterfly valve 19 is fixed to the right end of the positioning ring 17 by the first pin 18. The intermediate connecting housing 16 is threaded together with the upper end of the lower housing 6.

[0028] The second-stage blowout preventer assembly mainly consists of a wear-resistant alloy layer 20, a second pin 21, a first valve core 22, a second butterfly valve 23, a second spring 24, a second O-ring seal 25, and a second connecting housing 26. The first valve core 22 has a wear-resistant alloy layer at the contact point with the lower housing 6. The second butterfly valve 23 is fixed to the left end of the inner hole of the first valve core 22 by the second pin 21. The first valve core 22 has a spring seat, and the second spring 24 is installed in the spring seat. The second connecting housing 26 has sealing grooves, and the second O-ring seal 25 is installed in these sealing grooves. The second connecting housing 26 is threaded to the lower end of the lower housing 6.

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

[0030] The pressure balancing system mainly consists of a balancing pressure hole 40, a cone valve core 41, a second O-ring seal 42, a fourth spring 43, and a high-pressure fluid channel 44. The outer circular end face of the third connecting housing 33 is provided with a balancing pressure hole 40, and the outer circular end face of the third connecting housing 33 is provided with an opening groove for 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 housing 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 housing 33 and the sealing joint 8 are connected.

[0031] The outer ring blowout preventer assembly mainly consists of a positioning pressure ring 50, a main pressure ring 51, a first rubber sleeve 52, a first spacer ring 53, a second rubber sleeve 54, a second spacer ring 55, a third rubber sleeve 56, a fourth rubber sleeve 57, a fourth spacer ring 58, a fifth rubber sleeve 59, a retaining ring 501, a rubber sleeve seat 502, a guide joint 503, and a tail end positioning cylinder 504. The positioning pressure ring 50 is installed at the stepped end face of the sealing joint 8. The main pressure ring 51 is installed between the positioning pressure ring 50 and the first rubber sleeve 52. The first spacer ring 53 is installed between the first rubber sleeve 52 and the second rubber sleeve 54. The second spacer ring 55 is installed between the second rubber sleeve 54 and the third rubber sleeve 56. The third spacer ring 58 is installed between the third rubber sleeve 57 and the fourth rubber sleeve 59. The fourth spacer ring 58 is installed between the fourth rubber sleeve 57 and the fifth rubber sleeve 59. The fifth rubber sleeve 59 is tightly fitted to the left end face of the retaining ring 501. The rubber sleeve 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 sleeve seat 502 by a threaded connection. The tail positioning cylinder 504 is embedded in the annular groove of the retaining ring 501.

[0032] Figures 2-4 This is a schematic diagram illustrating the working process of the high-pressure deep well multi-stage blowout preventer of the present invention, as shown below. Figure 2 , Figure 3 As shown, when the tool is lowered into the well, during normal drilling, the drilling fluid pressure pumped into the wellhead is higher than the formation pressure. The drilling fluid enters the cavity between the upper housing 10 and the first connecting housing 11, pushing the thrust cylinder 12 and the cylindrical piston 14 to the right. The cylindrical piston 14 then pushes the first butterfly valve 19 to rotate counterclockwise, thus opening the first butterfly valve 19. Furthermore, since the drilling fluid pressure pumped into the well is higher than the formation pressure, the drilling fluid continues to move downwards, quickly opening the second butterfly valve 23. The drilling fluid then enters the lower chamber and finally reaches the drill bit position.

[0033] like Figure 3As shown, when the formation pressure is relatively high and slightly higher than the drilling fluid pressure, the formation fluid enters the 301 and main valve core positions. The high-pressure formation fluid will push the main valve core 301 and valve stem 36 to the left until the main valve core 301 abuts against the right end face of the outer sleeve 37, so that the upper drilling fluid pressure and the upward formation fluid pressure are balanced, and the normal drilling state is achieved.

[0034] like Figure 4 As shown, when the formation pressure is high, significantly higher than the drilling fluid pressure, a portion of the formation fluid enters the main valve core 301. The high-pressure formation fluid pushes the main valve core 301 and valve stem 36 to the left until the main valve core 301 abuts against the right end face of the outer sleeve 37. The other portion continues to flow upwards, passing through the second butterfly valve 23, and then pushes the second butterfly valve 23 and the first valve core 22 to the left, causing the second butterfly valve 23 and the first valve core 22 to close.

[0035] like Figure 4 As shown, when the formation pressure is high and significantly higher than the drilling fluid pressure, some of the formation fluid causes the main valve core 301, the second butterfly valve 23, and the first valve core 22 to close. Meanwhile, some of the formation fluid continues to flow upwards 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 it is in a vertical position, i.e., closed.

[0036] like Figure 4 As shown, when the external pressure of the blowout preventer system is too high, the high-pressure fluid pushes the cone valve core 41, causing the cone valve core 41 to compress the fourth spring 43 and move downwards. The high-pressure fluid enters the outer annular blowout preventer assembly 5 through the high-pressure fluid channel 44, pushing the positioning pressure ring 50, the main pressure ring 51, and the rubber sleeve and spacer ring downwards. The rubber sleeve is axially compressed and laterally expanded, then tightly adheres to the well wall 9, sealing the outer annular flow channel and preventing the high-pressure formation fluid in the outer annular space from flowing back up, thus providing safety protection for the outer annular space. Similarly, the high-pressure fluid in the outer annular space can reach the position of the cone valve core 41 through the balance pressure hole 40, and can also cause the rubber sleeve to expand and seal the outer annular space.

[0037] Example 1

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

[0039] Example 2

[0040] Based on Embodiment 1, the first-stage blowout preventer assembly 1 includes a hollow sleeve-shaped upper housing 10, an intermediate connecting housing 16, and a positioning ring 17 connected in sequence. A first connecting housing 11 is coaxially arranged outside the upper housing 10, and a cavity is provided between the upper housing 10 and the first connecting housing 11. A thrust cylinder 12 is installed in 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 housing 16, and a spring mounting cavity is provided between the cylindrical piston 14 and the intermediate connecting housing 16. A first spring 15 is installed in the spring mounting cavity. The end of the thrust cylinder 12 is close to one end face 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] Based on Embodiment 2, the second-stage blowout preventer assembly includes a lower housing 6, one end of which is connected to an intermediate connecting housing 16, and the other end of which 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 area between the first valve core 22 and the lower housing 6. A second butterfly valve 23 is fixed on the first valve core 22 by a second pin 21. A second spring 24 is installed on the first valve core 22.

[0043] Example 4

[0044] Based on Embodiment 3, the third-stage blowout preventer includes a third connecting housing 33, which is connected to a second connecting housing 26. An outer sleeve 37 is coaxially arranged inside the third connecting housing 33. A valve stem housing 38 and a valve stem 36 are coaxially arranged inside the outer sleeve 37. One end of the valve stem housing 38 is connected to a lower positioning joint 34. A cavity is provided in the middle of the lower positioning joint 34. A third spring 35 is installed in the cavity. The second connecting housing 33 is threadedly connected to the lower positioning joint 34. The main valve core 301 is installed at the end of the valve stem 36 away from the lower positioning joint 34.

Claims

1. A high pressure deep well multi-stage blowout preventer, characterized in that: The blowout preventer assembly comprises a first blowout preventer assembly (1), a second blowout preventer assembly (2), a third blowout preventer assembly (3), a pressure balance system (4) and an outer annulus blowout preventer assembly (5) connected in sequence. The first blowout preventer assembly (1) comprises an upper hollow sleeve-shaped shell (10), an intermediate connecting shell (16) and a positioning ring (17) connected in sequence, the upper shell (10) is coaxially provided with a first connecting shell (11) outside, a cavity is provided between the upper shell (10) and the first connecting shell (11), a thrust cylinder (12) is installed at the cavity position, a sealing ring (13) is installed on the outer wall of the thrust cylinder (12); the intermediate connecting shell (16) is coaxially provided with a cylinder-shaped piston (14) inside, the cylinder-shaped piston (14) and the intermediate connecting shell (16) are provided with a spring installation cavity, the first spring (15) is installed in the spring installation cavity, the end of the thrust cylinder (12) abuts against one end face of the cylinder-shaped piston (14), the positioning ring (17) is located at the other end of the cylinder-shaped piston (14), the first butterfly valve (19) is installed on the positioning ring (17) through the first pin shaft (18); The second blowout preventer assembly comprises a lower shell (6), one end of the lower shell (6) is connected with the intermediate connecting shell (16), the other end of the lower shell (6) is connected with a second connecting shell (26), a first valve core (22) is arranged at the connection position of the lower shell (6) and the second connecting shell (26), a wear-resistant alloy layer (20) is arranged at the contact position of the first valve core (22) and the lower shell (6), a second butterfly valve (23) is fixed on the first valve core (22) through a second pin shaft (21), and a second spring (24) is installed on the first valve core (22); The third blowout preventer assembly comprises a third connecting shell (33), the third connecting shell (33) is connected with the second connecting shell (26), the third connecting shell (33) is coaxially provided with an outer sleeve (37) inside, the outer sleeve (37) is coaxially provided with a valve rod shell (38) and a valve rod (36) inside in sequence, one end of the valve rod shell (38) is connected with a lower positioning connector (34), a cavity is arranged in the middle of the lower positioning connector (34), a third spring (35) is installed at the cavity position, the second connecting shell (33) is threadedly connected with the lower positioning connector (34), and a main valve core (301) is installed at one end of the valve rod (36) away from the lower positioning connector (34); The pressure balance system (4) comprises a balance pressure hole (40) and a conical valve core (41), both the balance pressure hole (40) and the conical valve core (41) are arranged on the outer circular end face of the third connecting shell (33); the conical valve core (41) is installed with a fourth spring (43), a center connecting sleeve (7) is coaxially arranged at the center of the third connecting shell (33), one end of the center connecting sleeve (7) is arranged close to the main valve core (301), and the other end of the center connecting sleeve (7) is connected with a sealing connector (8). The outer annular space blowout preventer assembly (5) comprises sequentially connected positioning pressure ring (50), first rubber cylinder (52), second rubber cylinder (54), third rubber cylinder (56), fourth rubber cylinder (57) and fifth rubber cylinder (59); The positioning pressure ring (50) is installed at the stepped end face position 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 combined on one end face of the blocking ring (501), and the rubber cylinder seat (502) is connected in series at the middle position of the sealing joint (8).

2. The high pressure deep well multi-stage blowout preventer of claim 1, wherein: The area of the third connecting shell (33) where the center connecting sleeve (7) is located and the area where the sealing joint (8) is located are both provided with high-pressure fluid channels (44).

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