Underwater safety valve for hydraulic oil extraction of offshore oil well

Abstract

The invention relates to the technical field of safety valves, in particular to an underwater safety valve for hydraulic oil extraction of an offshore oil well, which comprises a shell assembly, the shell assembly comprises a valve body shell, a water inlet pipe and a water outlet pipe are arranged at the upper end and the lower end in the valve body shell, a grading cavity is formed in the side face of the water inlet pipe, and a lower pipe assembly is mounted in the grading cavity; a grading assembly is installed in the lower pipe assembly, a supporting frame and a displacement plate are installed at the position, located at the bottom of the grading assembly, of the lower pipe assembly, and a moving pipe is installed on the side face of the displacement plate. By arranging the upper pipe assembly, when the flow speed is increased, the pressure of liquid on the upper portion of an opening and closing plate is gradually increased, a second pressure rod moves towards the two sides, a springboard enables the opening and closing plate to move towards the inner side, a gap between the two opening and closing plates is reduced, the circulation amount is reduced, liquid is gradually discharged from an external tank body, the pressure of the upper portion is reduced, and the opening and closing plates move towards the two sides, and the gap is increased; the circulation amount is increased, and the constant outflow pressure of the liquid at the top tank body is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of safety valves, and more particularly to an underwater safety valve for hydraulic production of offshore oil wells. Background Art

[0002] A downhole safety valve is a device installed in an oil and gas well. It can be closed urgently in the event of a fire in the production facility, a pipeline rupture, or an irresistible natural disaster (such as an earthquake, hail, or a strong typhoon) to prevent blowouts and ensure the safety of oil and gas wells and production. It is also called an underwater safety valve in offshore operations.

[0003] The Chinese invention patent with the publication number of CN111561295A discloses a dual-channel underwater safety valve for hydraulic oil production in an offshore oil well, comprising a safety valve main pipe, a throat pipe fixedly connected to the middle of the outer side of the safety valve main pipe, a hydraulic expansion sealing mechanism is provided on the safety valve main pipe above the throat pipe, a high-pressure fluid is introduced into the safety valve main pipe to seal the hydraulic expansion sealing mechanism, and the expansion sealing mechanism does not rebound after the pressure is removed, a throat pipe piston valve is provided on the safety valve main pipe below the throat pipe, a high-pressure fluid is introduced into the safety valve main pipe to separate the throat pipe piston valve from the throat pipe sealing surface, so that the spent power fluid after the hydraulic oil production pump is driven to work and the output fluid of the oil well are output to the wellhead surface, a one-way valve is connected to the lower end of the safety valve main pipe, a high-pressure fluid is introduced into the safety valve main pipe to open the one-way valve, and the hydraulic medium smoothly passes to the bottom of the well, driving the hydraulic oil production pump installed at the bottom of the oil well to work. The present invention fills the gap that there is no matching downhole safety valve for the hydraulic oil pump, and effectively prevents the leakage of oil well fluid from polluting the ocean.

[0004] It can be seen that the underwater safety valves currently used in the exploitation process of offshore oil wells usually require the liquid on the well for control, and single-channel safety control cannot be achieved. In addition, the existing safety valves cannot achieve constant pressure. Not only does the pressure of the oil discharged vary greatly, but the pressure of the outflowing liquid cannot be accurately controlled. At the same time, the locking capacity of the safety valves currently used is insufficient, and the safety protection capacity of the safety valves is limited when a pipeline leak occurs at the bottom. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides an underwater safety valve for hydraulic production of marine oil wells to solve the problems existing in the above-mentioned background technology.

[0006] The present invention provides the following technical solutions: an underwater safety valve for hydraulic oil production in an offshore oil well, comprising a housing assembly, the housing assembly comprising a valve body housing, a water inlet pipe and a water outlet pipe are provided at the upper and lower ends of the interior of the valve body housing, a grading cavity is provided on the side of the water inlet pipe, a lower pipe assembly is installed inside the grading cavity, a grading assembly is installed inside the lower pipe assembly, a support frame and a displacement plate are installed on the lower pipe assembly at the bottom of the grading assembly, a moving pipe is installed on the side of the displacement plate, the grading cavity is connected to the water inlet pipe through a plurality of first water holes, a pressure measuring cavity and a constant pressure cavity are provided on the side of the water outlet pipe, an upper pipe assembly is installed inside the constant pressure cavity, the pressure measuring cavity is connected to the grading cavity through a second water hole, the water outlet pipe is connected to the constant pressure cavity through a plurality of third water holes, a pressure measuring tube is provided on the top of the pressure measuring cavity, a locking assembly is installed inside the pressure measuring tube; Furthermore, the upper pipe assembly includes an upper pipe main pipe, the outer side of which is fixedly connected with a lower ring, a first valve, an upper ring and a second valve from bottom to top, pressure plates are installed on both sides of the lower ring, automatic control valves are installed on the sides of the first valve and the upper ring, the automatic control valves are installed on the springboard bracket, and a closing plate is installed inside the second valve.

[0007] Furthermore, the automatic control valve includes a second pressure rod and an opening and closing plate, a third spring is installed on the outer side of the second pressure rod, a springboard is hinged between the third spring and the opening and closing plate, the opening and closing plate is composed of a baffle and a moving rod, and there is a gap between the two baffles.

[0008] Furthermore, the pressure plate includes a first pressure rod, a second spring is installed on the outside of the first pressure rod, the installation method of the pressure plate is the same as that of the automatic control valve, a control plate is installed on the outside of the first pressure rod, and the control plate is placed on both sides of the top of the double side frame.

[0009] Furthermore, the down tube assembly includes a down tube main pipe, a plurality of down tube sub-pipes are installed on the side of the down tube main pipe, a movable groove is opened on the top of the down tube sub-pipe, a connecting rod is installed inside the movable groove, and both ends of the connecting rod are respectively installed on the top of the connecting plate and the bottom of the movable tube.

[0010] Furthermore, the locking assembly includes a straight rod, which is installed inside the pressure measuring tube, a fourth spring is installed at the bottom of the outer side of the straight rod, a closing plate is fixedly connected to the top of the straight rod, and double side frames are fixedly connected to both sides of the straight rod.

[0011] Furthermore, the grading assembly includes a grading valve, the top of which is fixedly connected to a connecting plate, the side of the grading valve is composed of a semicircular groove and a spring inner rod, the bottom of the semicircular groove is provided with a plurality of grading openings, the outer side of the spring inner rod is fixedly connected to two spring baffles, and a first spring is installed on the outer side of the spring inner rod on the side of the spring baffle.

[0012] Furthermore, the displacement plate comprises a right-angle plate, a bevel is provided on the top of the right-angle plate, the bevel is installed between two spring baffles, and upper baffles are fixedly connected to both sides of the right-angle plate. A fifth spring is installed at the bottom of the upper baffle.

[0013] Furthermore, the top of the water outlet pipe is connected to the external tank body, and the bottom of the water inlet pipe is connected to the bottom oil pump.

[0014] Technical effects and advantages of the present invention: The present invention is advantageous in that when the flow rate increases, the pressure of the liquid on the opening and closing plate gradually increases, the second pressure rod moves to both sides, the springboard causes the opening and closing plate to move inward, the gap between the two opening and closing plates decreases, the flow rate decreases, the external tank body gradually releases liquid, the pressure on the upper part decreases, the opening and closing plate moves to both sides, the gap increases, the flow rate increases, and the constant outflow pressure of the liquid at the top tank body is achieved.

[0015] The present invention is provided with a grading component, which is conducive to increasing the liquid pressure so that the flow of a single grading component reaches the maximum value, and then the grading valve moves to the farthest point. The moving pipe enters the interior of the displacement plate to make it move downward, and the right-angle plate descends to unlock the inner rod of the spring. Multiple repeated movements increase multiple grading port outlets, thereby realizing multi-level precise control and management of liquid flow.

[0016] The present invention is provided with a locking assembly, which is beneficial for the first pressure rod to move to both sides when oil leakage occurs underwater and the pressure in the pipeline is greater than a threshold value, and the double-side frames rise to fix the closing plate inside the second valve. At this time, the liquid in the pipeline cannot circulate again, thereby achieving safe protection of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 It is a cross-sectional view of the overall structure of the present invention.

[0019] Figure 3 It is a schematic diagram of the structure of the housing assembly of the present invention.

[0020] Figure 4 It is a schematic structural diagram of the upper tube assembly of the present invention.

[0021] Figure 5 It is a cross-sectional view of the upper pipe main structure of the present invention.

[0022] Figure 6 It is a schematic diagram of the structure of the down tube assembly of the present invention.

[0023] Figure 7 It is a cross-sectional view of the lower tube and auxiliary tube structure of the present invention.

[0024] Figure 8 It is a schematic diagram of the hierarchical component structure of the present invention.

[0025] Fig. 9 It is a schematic diagram of the displacement plate structure of the present invention.

[0026] The accompanying drawings are marked as follows: 1. Shell assembly; 101. Valve body shell; 102. Water inlet pipe; 103. Water outlet pipe; 104. Grading chamber; 105. First water hole; 106. Second water hole; 107. Pressure measuring chamber; 108. Pressure measuring tube; 109. Third water hole; 110. Constant pressure chamber; 2. Lower pipe assembly; 201. Lower pipe main pipe; 202. Lower pipe auxiliary pipe; 203. Moving groove; 204. Connecting rod; 3. Grading assembly; 301. Grading valve; 302. Grading port; 303. Spring inner rod; 304. Spring baffle; 305. Connecting plate; 306. First spring; 4. Upper pipe assembly; 401. Upper pipe Main pipe; 402, lower ring; 403, first valve; 404, upper ring; 405, pressure plate; 4051, first pressure rod; 4052, second spring; 4053, control plate; 406, automatic control valve; 4061, second pressure rod; 4062, third spring; 4063, springboard; 4064, opening and closing plate; 407, springboard bracket; 408, second valve; 5, locking assembly; 501, straight rod; 502, fourth spring; 503, closing plate; 504, double-side frame; 6, support frame; 7, moving pipe; 8, displacement plate; 801, right-angle plate; 802, upper baffle; 803, fifth spring. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. In addition, the forms of the various structures recorded in the following embodiments are merely illustrative. The underwater safety valve for hydraulic production of marine oil wells involved in the present invention is not limited to the various structures recorded in the following embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0028] Reference Figure 1 and Figure 2The present invention provides an underwater safety valve for hydraulic oil production in an offshore oil well, comprising a housing component 1, the housing component 1 comprising a valve body housing 101, a water inlet pipe 102 and a water outlet pipe 103 are provided at the upper and lower ends of the valve body housing 101, a grading cavity 104 is provided on the side of the water inlet pipe 102, a lower pipe component 2 is installed inside the grading cavity 104, a grading component 3 is installed inside the lower pipe component 2, a support frame 6 and a displacement plate 8 are installed at the bottom of the lower pipe component 2, and a grading component 3 is installed on the side of the displacement plate 8. A movable pipe 7 is installed, the grading chamber 104 is connected to the water inlet pipe 102 through a plurality of first water holes 105, a pressure measuring chamber 107 and a constant pressure chamber 110 are provided on the side of the water outlet pipe 103, an upper pipe assembly 4 is installed inside the constant pressure chamber 110, the pressure measuring chamber 107 is connected to the grading chamber 104 through a second water hole 106, the water outlet pipe 103 is connected to the constant pressure chamber 110 through a plurality of third water holes 109, a pressure measuring tube 108 is provided on the top of the pressure measuring chamber 107, and a locking assembly 5 is installed inside the pressure measuring tube 108; In this embodiment, it should be specifically explained that: the top of the water outlet pipe 103 is connected to the external tank body, and the bottom of the water inlet pipe 102 is connected to the bottom oil pump.

[0029] The main difference between this embodiment and the prior art is that in this embodiment, the pressure difference change between the upper and lower oil wells is used to realize the graded processing of the fluid flow rate, and the precise control of the fluid flow is realized. At the same time, the pressure change of the liquid is used to realize the automatic start of the safety protection, and the single-channel downhole safety valve still has a good protection effect, which is specifically in the graded component 3, the upper pipe component 4, and the locking component 5; The above structure is the main structure of this embodiment, which solves the problem that the current single-channel downhole safety valve cannot achieve a good protection effect, and at the same time solves the problem that the pressure cannot be constant during oil production. The tank body and oil pump are existing structures, and this embodiment does not give a specific description of their specific structure and connection method.

[0030] Reference Figure 4 The upper pipe assembly 4 includes an upper pipe main pipe 401, and the outer side of the upper pipe main pipe 401 is fixedly connected with a lower ring 402, a first valve 403, an upper ring 404 and a second valve 408 from bottom to top, respectively. Pressure plates 405 are installed on both sides of the lower ring 402, and automatic control valves 406 are installed on the sides of the first valve 403 and the upper ring 404. The automatic control valve 406 is installed on a springboard bracket 407. A closing plate 503 is installed inside the second valve 408. When the flow rate increases, the internal pressure of the liquid in the upper part of the opening and closing plate 4064 gradually increases with the increase of the flow rate. The increase in the pressure in the pipe causes the second pressure rod 4061 to move to both sides. Under the rotation of the springboard 4063, the opening and closing plate 4064 moves inward, the gap between the two opening and closing plates 4064 is reduced, and the flow rate is reduced.

[0031] In this embodiment, it should be specifically explained that: as the external tank body gradually releases liquid, the pressure in the upper part decreases, the opening and closing plate 4064 moves to both sides, the gap increases, and the flow rate increases, thereby achieving a constant liquid outflow pressure at the top tank body.

[0032] Reference Figure 4 The locking assembly 5 includes a straight rod 501 , a fourth spring 502 is installed at the bottom of the outer side of the straight rod 501 , a closing plate 503 is fixedly connected to the top of the straight rod 501 , and double side frames 504 are fixedly connected to both sides of the straight rod 501 .

[0033] In this embodiment, it should be specifically explained that: the straight rod 501 is installed inside the pressure measuring tube 108, and as the pressure inside the pressure measuring chamber 107 increases, the locking assembly 5 always has an upward trend.

[0034] Reference Figure 5 The automatic control valve 406 includes a second pressure rod 4061 and an opening and closing plate 4064. A third spring 4062 is installed on the outer side of the second pressure rod 4061. A springboard 4063 is hinged between the third spring 4062 and the opening and closing plate 4064. The opening and closing plate 4064 is composed of a baffle and a moving rod. There is a minimum gap between the two baffles. The pressure plate 405 includes a first pressure rod 4051. A second spring 4052 is installed on the outer side of the first pressure rod 4051. The installation method of the pressure plate 405 is the same as that of the automatic control valve 406. A control plate 4053 is installed on the outer side of the first pressure rod 4051. The control plate 4053 is installed on the outer side of the first pressure rod 4051. 53 are placed on both sides of the top of the double-side frame 504. When oil leakage occurs underwater and the pressure in the pipeline is greater than the threshold, all the grading components 3 are at the farthest end of the moving position. At this time, as the pressure inside the upper pipe main 401 increases, the first pressure rod 4051 moves to both sides, and the control plate 4053 moves outward synchronously under the drive of the first pressure rod 4051. When it reaches the farthest end, it loses resistance to the double-side frame 504. The double-side frame 504 rises rapidly under the action of the liquid pressure inside the pressure measuring chamber 107, so that the closing plate 503 is fixed inside the second valve 408, thereby realizing the closure of the pipeline.

[0035] In this embodiment, it should be specifically explained that: when the internal pressure does not reach the threshold value, the increase in pressure inside the upper tube main pipe 401 will also cause the first pressure rod 4051 to move to both sides, and the locking assembly 5 has a tendency to move upward. However, since the control plate 4053 applies pressure to the double side frames 504, the locking assembly 5 does not move at this time, and the closing plate 503 does not affect the flow of liquid inside the upper tube main pipe 401.

[0036] Reference Figure 6The lower pipe assembly 2 includes a lower pipe main pipe 201, and a plurality of lower pipe sub-pipes 202 are installed on the side of the lower pipe main pipe 201. A moving groove 203 is opened on the top of the lower pipe sub-pipe 202, and a connecting rod 204 is installed inside the moving groove 203. The two ends of the connecting rod 204 are respectively installed on the top of the connecting plate 305 and the bottom of the moving pipe 7. When the flow rate increases, the grading valve 301 moves to the farthest point after the flow maximum value of a single grading assembly 3. At this time, the moving pipe 7 moves to the right side driven by the grading assembly 3 and enters the interior of the displacement plate 8 to push the displacement plate 8 to move downward.

[0037] In this embodiment, it should be specifically explained that the top of the lower pipe main tube 201 is connected to the pressure measuring chamber 107, and the liquid enters the lower pipe auxiliary tube 202 from the classification port 302, and enters the pressure measuring chamber 107 after flowing through the lower pipe main tube 201 and the second water hole 106.

[0038] Reference Figure 7-8 The grading component 3 includes a grading valve 301, a connecting plate 305 is fixedly connected to the top of the grading valve 301, the side of the grading valve 301 is composed of a semicircular groove and a spring inner rod 303, a plurality of grading ports 302 are opened at the bottom of the semicircular groove, two spring baffles 304 are fixedly connected to the outer side of the spring inner rod 303, and a first spring 306 is installed on the side of the spring baffle 304 on the outer side of the spring inner rod 303. When the liquid flows, the liquid pressure pushes the grading valve 301 to overcome the pressure of the first spring 306 and move to the right side, so that the grading port 302 extends from the inside of the lower tube auxiliary pipe 202, and the liquid enters the inside of the lower tube auxiliary pipe 202 from the grading port 302.

[0039] In this embodiment, it is necessary to specifically explain that: when the flow rate increases, the liquid pressure in the grading valve 301 increases the moving distance of the grading valve 301, the number of grading ports 302 used increases, and the multiple grading ports 302 increase its adaptability. An alarm is installed on the top of the grading component 3. When the grading component 3 at the highest point moves, the alarm starts to transmit an electrical signal to remind the staff that the pressure at the valve has reached the threshold.

[0040] Reference Fig. 9 The displacement plate 8 includes a right-angle plate 801, and a slope is provided on the top of the right-angle plate 801, which is installed between the two spring baffles 304. The upper baffle 802 is fixedly connected to both sides of the right-angle plate 801. The bottom of the upper baffle 802 is installed with a fifth spring 803. When the flow rate increases, the liquid pressure in the grading valve 301 increases the moving distance of the grading valve 301. The moving tube 7 moves to the right side and enters the interior of the displacement plate 8 under the drive of the grading component 3. The bottom slope of the moving tube 7 pushes the displacement plate 8 to move downward, and the top slope of the right-angle plate 801 moves down from between the two spring inner rods 303, thereby unlocking the movement of the spring inner rod 303.

[0041] In this embodiment, it should be specifically explained that: after the flow rate decreases, the movable tube 7 moves out from the right-angle plate 801. At this time, the multiple grading components 3 are restored to their original positions inside the lower tube auxiliary tube 202 under the action of the first spring 306. Under the action of the inclined surface, the spring baffle 304 slides on the inclined surface so that it can move normally to the left. The right-angle plate 801 is still between the spring baffles 304, so that it cannot move directly to the right.

[0042] Working principle of the present invention: The main problem solved by this embodiment is: utilizing the pressure difference change between the upper and lower oil wells to achieve graded processing of the fluid flow rate, thereby achieving precise control of the fluid flow circulation, and at the same time utilizing the pressure change of the liquid to realize automatic start of safety protection, thereby achieving a single-channel downhole safety valve still having a good protection effect, solving the problem that the current single-channel downhole safety valve cannot achieve a good protection effect, and at the same time solving the problem that the pressure cannot be constant during oil production.

[0043] The specific steps are as follows: Start the bottom oil well pump, and the oil enters the housing assembly 1 from the water inlet pipe 102. As the internal pressure of the water inlet pipe 102 gradually increases, the liquid in the water inlet pipe 102 enters the grading valve 301 in the lower pipe auxiliary pipe 202 from the first water hole 105. The liquid pressure pushes the grading valve 301 to overcome the pressure of the first spring 306 and move to the right, so that the grading port 302 extends from the lower pipe auxiliary pipe 202. The liquid enters the lower pipe auxiliary pipe 202 from the grading port 302, and enters the pressure measuring chamber 107 after flowing through the lower pipe main pipe 201 and the second water hole 106. Then, the liquid enters the upper pipe main pipe 401 from the top of the pressure measuring chamber 107, and enters the water outlet pipe 103 through the third water hole 109 and is collected in the external tank installed on the top. When the flow rate increases, the liquid pressure at the water inlet pipe 102 and the grading valve 301 increases, and the liquid pressure in the grading valve 301 increases the moving distance of the grading valve 301, and the number of grading ports 302 used increases. After the flow maximum value of a single grading component 3 is reached, the grading valve 301 moves to the farthest point. At this time, since a connecting rod 204 is installed on the top of the connecting plate 305, and the top of the connecting rod 204 is installed on the moving tube 7, the moving tube 7 moves to the right side under the drive of the grading component 3 and enters the interior of the displacement plate 8. The bottom inclined surface of the moving tube 7 pushes the displacement plate 8 to move downward, and the top inclined surface of the right-angle plate 801 descends and moves out from between the two spring inner rods 303, realizing the unlocking of the movement of the spring inner rod 303. At this time, the grading component 3 at the top begins to repeat the above movement to increase the outlet of the grading port 302. After the fluid enters the interior of the upper pipe main tube 401, the opening and closing plate 4064 divides the upper pipe main tube 401 into two parts, the internal pressure of the upper part of the liquid gradually increases with the increase of the flow rate. The increase of the pressure in the tube causes the second pressure rod 4061 to move to both sides. Under the rotation of the springboard 4063, the opening and closing plate 4064 moves inward, the gap between the two opening and closing plates 4064 decreases, and the flow rate decreases. As the external tank gradually releases liquid, the pressure in the upper part decreases, the opening and closing plate 4064 moves to both sides, the gap increases, and the flow rate increases, thereby achieving a constant outflow pressure of the liquid at the top tank. When oil leakage occurs underwater and the pressure in the pipeline is greater than the threshold, all the grading components 3 are at the farthest end of the moving position, and the liquid at the lower pipe component 2 enters the pressure measuring chamber 107. The increase in pressure at the pressure measuring chamber 107 causes the locking component 5 inside the pressure measuring tube 108 to have a tendency to move upward rapidly. However, due to the pressure exerted by the control board 4053 on the double-side frame 504 at low pressure, the double-side frame 504 cannot move. At this time, as the pressure inside the upper pipe main 401 increases, the first pressure rod 4051 moves to both sides, and the control board 4053 moves synchronously outward under the drive of the first pressure rod 4051. When reaching the farthest end, the resistance to the double-side frame 504 is lost. The double-side frame 504 rises rapidly under the action of the liquid pressure inside the pressure measuring chamber 107, so that the closing plate 503 is fixed inside the second valve 408, thereby closing the pipeline. At this time, the liquid in the pipeline cannot circulate again, thereby achieving safety protection.

[0044] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An underwater safety valve for hydraulic oil production in an offshore oil well, comprising a housing assembly (1), Features: The housing assembly (1) comprises a valve body housing (101), wherein a water inlet pipe (102) and a water outlet pipe (103) are provided at the upper and lower ends of the valve body housing (101), a grading chamber (104) is provided on the side of the water inlet pipe (102), a lower pipe assembly (2) is installed inside the grading chamber (104), a grading assembly (3) is installed inside the lower pipe assembly (2), a support frame (6) and a displacement plate (8) are installed at the bottom of the grading assembly (3), a moving pipe (7) is installed on the side of the displacement plate (8), and the grading chamber (104) and the water inlet pipe (102) are connected to each other. The pipes (102) are connected to each other through a plurality of first water holes (105); a pressure measuring chamber (107) and a constant pressure chamber (110) are provided on the side of the water outlet pipe (103); an upper pipe assembly (4) is installed inside the constant pressure chamber (110); the pressure measuring chamber (107) and the grading chamber (104) are connected through a second water hole (106); the water outlet pipe (103) and the constant pressure chamber (110) are connected through a plurality of third water holes (109); a pressure measuring tube (108) is provided on the top of the pressure measuring chamber (107); a locking assembly (5) is installed inside the pressure measuring tube (108); The upper pipe assembly (4) comprises an upper pipe main pipe (401), the outer side of which is fixedly connected with a lower ring (402), a first valve (403), an upper ring (404) and a second valve (408) from bottom to top, respectively; pressure plates (405) are installed on both sides of the lower ring (402); automatic control valves (406) are installed on the sides of the first valve (403) and the upper ring (404); the automatic control valve (406) is installed on a springboard bracket (407); and a closing plate (503) is installed inside the second valve (408).

2. An underwater safety valve for hydraulic production of marine oil wells according to claim 1, Features: The automatic control valve (406) comprises a second pressure rod (4061) and an opening and closing plate (4064); a third spring (4062) is installed on the outer side of the second pressure rod (4061); a springboard (4063) is hinged between the third spring (4062) and the opening and closing plate (4064); the opening and closing plate (4064) consists of a baffle and a moving rod; and a gap exists between the two baffles.

3. The underwater safety valve for hydraulic production of marine oil wells according to claim 1, Features: The pressure plate (405) comprises a first pressure rod (4051), a second spring (4052) is installed on the outer side of the first pressure rod (4051), the pressure plate (405) is installed in the same manner as the automatic control valve (406), a control plate (4053) is installed on the outer side of the first pressure rod (4051), and the control plate (4053) is placed on both sides of the top of the double-side frame (504).

4. The underwater safety valve for hydraulic production of offshore oil wells according to claim 1, Features: The lower tube assembly (2) comprises a lower tube main tube (201), a plurality of lower tube auxiliary tubes (202) are installed on the side of the lower tube main tube (201), a movable groove (203) is opened on the top of the lower tube auxiliary tube (202), a connecting rod (204) is installed inside the movable groove (203), and two ends of the connecting rod (204) are respectively installed on the top of the connecting plate (305) and the bottom of the movable tube (7).

5. The underwater safety valve for hydraulic production of offshore oil wells according to claim 1, Features: The locking assembly (5) comprises a straight rod (501), wherein the straight rod (501) is installed inside the pressure measuring tube (108), a fourth spring (502) is installed at the bottom of the outer side of the straight rod (501), a closing plate (503) is fixedly connected to the top of the straight rod (501), and double side frames (504) are fixedly connected to both sides of the straight rod (501).

6. The underwater safety valve for hydraulic production of offshore oil wells according to claim 1, Features: The grading assembly (3) comprises a grading valve (301), the top of the grading valve (301) being fixedly connected to a connecting plate (305), the side of the grading valve (301) being composed of a semicircular groove and a spring inner rod (303), the bottom of the semicircular groove being provided with a plurality of grading openings (302), the outer side of the spring inner rod (303) being fixedly connected to two spring baffles (304), and the outer side of the spring inner rod (303) being located on the side of the spring baffle (304) being installed with a first spring (306).

7. The underwater safety valve for hydraulic production of offshore oil wells according to claim 1, Features: The displacement plate (8) comprises a right-angle plate (801), the top of the right-angle plate (801) is provided with an inclined surface, the inclined surface is installed between two spring baffles (304), and upper baffles (802) are fixedly connected to both sides of the right-angle plate (801). A fifth spring (803) is installed at the bottom of the upper baffle (802).

8. The underwater safety valve for hydraulic production of offshore oil wells according to claim 1, Features: The top of the water outlet pipe (103) is connected to the external tank body, and the bottom of the water inlet pipe (102) is connected to the bottom oil pump.

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