An underwater safety valve for hydraulic oil production in an offshore oil well

Abstract

The present invention relates to the technical field of safety valves, and more specifically discloses an underwater safety valve for hydraulic oil production in offshore oil wells, which includes a housing assembly. The housing assembly includes a valve body housing. An inlet pipe and an outlet pipe are provided at the upper and lower ends inside the valve body housing. A grading chamber is provided on the side of the inlet pipe. A lower pipe assembly is installed inside the grading chamber. A grading assembly is installed inside the lower pipe assembly. A support frame and a displacement plate are installed at the bottom of the lower pipe assembly where the lower pipe assembly is located on the grading assembly. A movable pipe is installed on the side of the displacement plate; by providing an upper pipe assembly in the present invention, when the flow rate increases, the liquid pressure on the upper part of 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 gradually discharges liquid, the pressure on the upper part decreases, the opening and closing plate moves to both sides, the gap increases, and the flow rate increases, realizing the constancy of the liquid outflow pressure at the top tank.

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 oil production in offshore oil wells. Background Art

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

[0003] Chinese Patent Invention Publication No. CN111561295A discloses a dual-channel underwater safety valve for hydraulic oil production in offshore oil wells, which includes a main safety valve pipe. A throat pipe is fixedly connected to the middle part outside the main safety valve pipe. A hydraulic expansion sealing mechanism is sleeved on the main safety valve pipe above the throat pipe. High-pressure fluid is introduced into the main safety valve pipe to seat the hydraulic expansion sealing mechanism, and the expansion sealing mechanism does not rebound after the pressure is removed. A throat pipe piston valve is sleeved on the main safety valve pipe below the throat pipe. High-pressure fluid is introduced into the main safety valve pipe to separate the throat pipe piston valve from the throat pipe sealing surface, so that the exhausted power fluid after driving the hydraulic oil pump and the produced fluid of the oil well are output to the wellhead ground. A check valve is connected to the lower end of the main safety valve pipe. High-pressure fluid is introduced into the main safety valve pipe to open the check valve, and the hydraulic medium smoothly leads to the bottom of the well to drive the hydraulic oil pump installed at the bottom of the oil well to work. The present invention fills the gap of the lack of a supporting downhole safety valve for hydraulic oil pumps 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 process of offshore oil well exploitation usually need to be controlled by liquids on the wellhead, and cannot achieve single-channel safety control. In addition, the existing safety valves cannot achieve constant pressure. Not only does the pressure of the extracted oil fluid change greatly, but also the pressure of the outflowing liquid cannot be accurately controlled. At the same time, the locking ability of the currently used safety valves is insufficient, and the safety protection ability of the safety valve 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 oil production in offshore oil wells to solve the problems existing in the above-mentioned background art.

[0006] The present invention provides the following technical solution: an underwater safety valve for hydraulic oil production in an offshore oil well, comprising a housing assembly. The housing assembly includes a valve body housing. At the upper and lower ends inside the valve body housing, a water inlet pipe and a water outlet pipe are provided. On the side of the water inlet pipe, a grading chamber is provided. Inside the grading chamber, a lower pipe assembly is installed. Inside the lower pipe assembly, a grading assembly is installed. At the bottom of the grading assembly, the lower pipe assembly is provided with a support frame and a displacement plate. On the side of the displacement plate, a moving pipe is installed. The grading chamber and the water inlet pipe are communicated through a plurality of first water holes. On the side of the water outlet pipe, a pressure measurement chamber and a constant pressure chamber are provided. Inside the constant pressure chamber, an upper pipe assembly is installed. The pressure measurement chamber and the grading chamber are communicated through a second water hole. The water outlet pipe and the constant pressure chamber are communicated through a plurality of third water holes. At the top of the pressure measurement chamber, a pressure measurement pipe is provided. Inside the pressure measurement pipe, a locking assembly is installed.

[0007] Further, the upper pipe assembly includes an upper pipe main body. From bottom to top on the outside of the upper pipe main body, a lower ring, a first valve, an upper ring, and a second valve are respectively fixedly connected. On both sides of the lower ring, pressure plates are installed. On the sides of the first valve and the upper ring, automatic control valves are installed. The automatic control valves are installed on the springboard brackets. Inside the second valve, a closing plate is installed.

[0008] Further, the automatic control valve includes a second pressure rod and an opening and closing plate. A third spring is installed on the outside 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. There is a gap between the two baffles.

[0009] Further, 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. The control plate is placed on both sides of the top of the double-sided frame.

[0010] Further, the lower pipe assembly includes a lower pipe main body. A plurality of lower pipe auxiliary pipes are installed on the side of the lower pipe main body. A moving groove is provided at the top of the lower pipe auxiliary pipe. Inside the moving groove, a connecting rod is installed. The two ends of the connecting rod are respectively installed on the top of the connecting plate and the bottom of the moving pipe.

[0011] Further, the locking assembly includes a straight rod. The straight rod is installed inside the pressure measurement pipe. A fourth spring is installed at the bottom on the outside of the straight rod. A closing plate is fixedly connected to the top of the straight rod. Double-sided frames are fixedly connected to both sides of the straight rod.

[0012] Further, the grading assembly includes a grading valve. A connecting plate is fixedly connected to the top of the grading valve. The side of the grading valve is composed of a semi-circular groove and a spring inner rod. A plurality of grading ports are provided at the bottom of the semi-circular groove. Two spring baffles are fixedly connected to the outside of the spring inner rod. A first spring is installed on the outside of the spring inner rod on the side of the spring baffle.

[0013] Further, the displacement plate includes a right-angle plate. An inclined surface is provided at the top of the right-angle plate, and the inclined surface is installed between two spring baffles. Upper baffles are fixedly connected to both sides of the right-angle plate. A fifth spring is installed at the bottom of the upper baffles.

[0014] Further, 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.

[0015] The technical effects and advantages of the present invention:

[0016] In the present invention, by providing an upper pipe assembly, when the flow rate increases, the liquid pressure on the upper part of 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 inwards, the gap between the two opening and closing plates decreases, the flow rate decreases, the external tank body gradually discharges liquid, the upper part pressure decreases, the opening and closing plate moves to both sides, the gap increases, and the flow rate increases, realizing the constancy of the liquid outflow pressure at the top tank body.

[0017] In the present invention, by providing a grading assembly, when the liquid pressure increases and the flow of a single grading assembly reaches the maximum value, the grading valve moves to the farthest position, the moving pipe enters into the displacement plate and causes it to move downward, the right-angle plate descends to unlock the spring inner rod, and the repeated movements increase the outlets of multiple grading ports, realizing the multi-level precise control and management of the liquid flow rate.

[0018] In the present invention, by providing a locking assembly, when oil leakage occurs underwater and the pressure in the pipeline is greater than the threshold value, the first pressure rod moves to both sides, the double-sided frame rises to fix the closing plate inside the second valve, and at this time the liquid in the pipeline cannot flow again, realizing the safety protection of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 is a sectional view of the overall structure of the present invention.

[0021] Figure 3 is a schematic diagram of the structure of the housing assembly of the present invention.

[0022] Figure 4 is a schematic diagram of the structure of the upper pipe assembly of the present invention.

[0023] Figure 5 is a sectional view of the main upper pipe of the present invention.

[0024] Figure 6 is a schematic diagram of the structure of the lower pipe assembly of the present invention.

[0025] Figure 7 is a sectional view of the auxiliary lower pipe of the present invention.

[0026] Figure 8 This is a schematic structural diagram of the grading component of the present invention.

[0027] Figure 9 This is a schematic structural diagram of the displacement plate of the present invention.

[0028] The reference numerals are: 1. housing assembly; 101. valve body housing; 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 pipe; 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 component; 301. grading valve; 302. grading port; 303. inner spring 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. spring board; 4064. opening and closing plate; 407. spring board support; 408. second valve; 5. locking component; 501. straight rod; 502. fourth spring; 503. closing plate; 504. double-sided frame; 6. support frame; 7. moving pipe; 8. displacement plate; 801. right-angle plate; 802. upper baffle; 803. fifth spring. Detailed implementation manners

[0029] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the accompanying drawings in the present invention. In addition, the forms of each structure described in the following embodiments are merely examples, and an underwater safety valve for hydraulic oil production in an offshore oil well related to the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0030] Refer to Figure 1 and Figure 2, the present invention provides an underwater safety valve for hydraulic oil production in an offshore oil well, including a housing assembly 1. The housing assembly 1 includes a valve body housing 101. At the upper and lower ends inside the valve body housing 101, a water inlet pipe 102 and a water outlet pipe 103 are provided. On the side of the water inlet pipe 102, a grading chamber 104 is provided. Inside the grading chamber 104, a lower pipe assembly 2 is installed. Inside the lower pipe assembly 2, a grading assembly 3 is installed. At the bottom of the lower pipe assembly 2 where it is located at the bottom of the grading assembly 3, a support frame 6 and a displacement plate 8 are installed. On the side of the displacement plate 8, a moving pipe 7 is installed. The grading chamber 104 and the water inlet pipe 102 are connected through a plurality of first water holes 105. On the side of the water outlet pipe 103, a pressure measurement chamber 107 and a constant pressure chamber 110 are provided. Inside the constant pressure chamber 110, an upper pipe assembly 4 is installed. The pressure measurement 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. At the top of the pressure measurement chamber 107, a pressure measurement pipe 108 is provided. Inside the pressure measurement pipe 108, a locking assembly 5 is installed;

[0031] In this embodiment, it should be specifically noted that: the top of the water outlet pipe 103 is connected to an external tank body, and the bottom of the water inlet pipe 102 is connected to a bottom oil pump.

[0032] 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 utilized to achieve the grading treatment of the fluid flow rate, realizing the precise control of the fluid flow circulation. At the same time, the automatic start of safety protection is realized by using the pressure change of the liquid, and it is realized that the single-channel downhole safety valve still has a good protection effect, specifically in the grading assembly 3, the upper pipe assembly 4, and the locking assembly 5;

[0033] 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 the oil production process. The tank body and the oil pump are existing structures, and the specific structures and connection methods thereof are not specifically described in this embodiment.

[0034] Refer to Figure 4 , the upper pipe assembly 4 includes an upper pipe main body 401. From bottom to top on the outside of the upper pipe main body 401, a lower ring 402, a first valve 403, an upper ring 404, and a second valve 408 are fixedly connected respectively. On both sides of the lower ring 402, pressure plates 405 are installed. On the sides of the first valve 403 and the upper ring 404, self-control valves 406 are installed. The self-control valves 406 are installed on a springboard support 407. Inside the second valve 408, a closing plate 503 is installed. When the flow rate increases, the pressure of the liquid in the upper part of the opening and closing plate 4064 gradually increases as the flow rate increases. The increase in the pressure inside 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, and the gap between the two opening and closing plates 4064 decreases, and the flow rate decreases.

[0035] In this embodiment, it should be specifically noted that as the external tank gradually discharges 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.

[0036] Refer to Figure 4 , the locking assembly 5 includes a straight rod 501, a fourth spring 502 is installed at the bottom outside the straight rod 501, a closing plate 503 is fixedly connected to the top of the straight rod 501, and double-sided frames 504 are fixedly connected to both sides of the straight rod 501.

[0037] In this embodiment, it should be specifically noted that the straight rod 501 is installed inside the pressure measuring tube 108. As the pressure in the pressure measuring chamber 107 rises, the locking assembly 5 always has an upward trend.

[0038] Refer to 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 outside 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 outside the first pressure rod 4051. The pressure plate 405 is installed in the same way as the automatic control valve 406. A control plate 4053 is installed outside the first pressure rod 4051. The control plate 4053 is placed on both sides of the top of the double-sided frame 504. When oil leaks underwater and the pressure in the pipeline is greater than the threshold value, at this time all the grading components 3 are at the farthest end of the moving position. At this time, as the pressure in the upper pipe main pipe 401 increases, the first pressure rod 4051 moves to both sides, and the control plate 4053 moves synchronously to the outside under the drive of the first pressure rod 4051. When it reaches the farthest end, it loses the resistance to the double-sided frame 504. The double-sided frame 504 rises rapidly under the action of the liquid pressure in the pressure measuring chamber 107, so that the closing plate 503 is fixed inside the second valve 408 to achieve the closure of the pipeline.

[0039] In this embodiment, it should be specifically noted that when the internal pressure does not reach the threshold value, the increase in the pressure in the upper pipe main pipe 401 will also cause the first pressure rod 4051 to move to both sides, and the locking assembly 5 has an upward movement trend. However, since the control plate 4053 applies pressure to the double-sided frame 504, the locking assembly 5 does not move at this time, and the closing plate 503 does not affect the liquid flow inside the upper pipe main pipe 401.

[0040] Refer to Figure 6, the lower pipe assembly 2 includes a lower pipe main pipe 201, and a plurality of lower pipe auxiliary pipes 202 are installed on the side of the lower pipe main pipe 201. A moving groove 203 is opened at the top of the lower pipe auxiliary 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 at the top of the connecting plate 305 and the bottom of the moving pipe 7. When the flow rate increases, after the maximum circulation value of a single grading component 3, the grading valve 301 moves to the farthest position. At this time, the moving pipe 7 moves to the right under the drive of the grading component 3 and enters the inside of the displacement plate 8, pushing the displacement plate 8 downward.

[0041] In this embodiment, it should be specifically noted that: the top of the lower pipe main pipe 201 is communicated with the pressure measuring chamber 107, and the liquid enters the inside of 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.

[0042] Refer to Figures 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 semi-circular groove and a spring inner rod 303. A plurality of grading ports 302 are opened at the bottom of the semi-circular groove. Two spring baffles 304 are fixedly connected to the outside of the spring inner rod 303. A first spring 306 is installed on the outside of the spring inner rod 303 on the side of the spring baffle 304. When the liquid flows, the liquid pressure pushes the grading valve 301 to move to the right against the pressure of the first spring 306, so that the grading port 302 extends out of the inside of the lower pipe auxiliary pipe 202, and the liquid enters the inside of the lower pipe auxiliary pipe 202 from the grading port 302.

[0043] In this embodiment, it should be specifically noted that: when the flow rate increases, the liquid pressure in the grading valve 301 causes the moving distance of the grading valve 301 to increase, and the number of grading ports 302 in use increases. The multiple grading ports 302 increase its adaptability. An alarm is installed at the top of the grading component 3. When the highest grading component 3 moves, the alarm is activated to transmit an electrical signal to remind the staff that the pressure at the valve reaches the threshold.

[0044] Refer to Figure 9 , the displacement plate 8 includes a right-angle plate 801. An inclined surface is opened at the top of the right-angle plate 801. The inclined surface is installed between the two spring baffles 304. 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. When the flow rate increases, the liquid pressure in the grading valve 301 causes the moving distance of the grading valve 301 to increase. The moving pipe 7 moves to the right under the drive of the grading component 3 and enters the inside of the displacement plate 8. The bottom inclined surface of the moving pipe 7 pushes the displacement plate 8 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 movement unlocking of the spring inner rod 303.

[0045] In this embodiment, it should be specifically noted that after the flow rate decreases, the moving pipe 7 moves out from the right-angle plate 801. At this time, the multiple grading components 3 return to their original positions under the action of the first spring 306 inside the lower pipe secondary pipe 202. Under the action of the inclined plane, the spring baffle 304 slides at the inclined plane so that it can move normally to the left. The right-angle plate 801 is still between the spring baffles 304, preventing it from moving directly to the right.

[0046] The working principle of the present invention:

[0047] The main problems solved in this embodiment are as follows: By utilizing the pressure difference change between the upper and lower oil wells to achieve the grading treatment of the fluid flow rate, the precise control of the fluid flow is realized. At the same time, by utilizing the pressure change of the liquid, the automatic start of the safety protection is realized, and it is ensured that the single-channel downhole safety valve still has 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 the oil production process.

[0048] The specific steps are as follows:

[0049] Start the bottom oil well pump. The oil liquid enters the inside of the housing assembly 1 from the water inlet pipe 102. As the pressure inside the water inlet pipe 102 gradually increases, the liquid inside the water inlet pipe 102 enters the grading valve 301 inside the lower pipe secondary pipe 202 from the first water hole 105. The liquid pressure pushes the grading valve 301 to move to the right against the pressure of the first spring 306, causing the grading port 302 to extend out from the inside of the lower pipe secondary pipe 202. The liquid enters the inside of the lower pipe secondary pipe 202 from the grading port 302, and after flowing through the lower pipe main pipe 201 and the second water hole 106, it enters the pressure measurement chamber 107. Subsequently, the liquid enters the upper pipe main pipe 401 from the top of the pressure measurement chamber 107 and is collected into the external tank installed at the top through the third water hole 109 into the water outlet pipe 103.

[0050] When the flow rate increases, the liquid pressure at the water inlet pipe 102 and the grading valve 301 increases. The liquid pressure inside the grading valve 301 causes the moving distance of the grading valve 301 to increase, and the number of grading ports 302 in use increases. After reaching the maximum flow value of a single grading component 3, the grading valve 301 moves to the farthest position. At this time, since the connecting rod 204 is installed at the top of the connecting plate 305 and the top of the connecting rod 204 is installed on the moving pipe 7, the moving pipe 7 moves to the right under the drive of the grading component 3 and enters the inside of the displacement plate 8. The bottom inclined plane of the moving pipe 7 pushes the displacement plate 8 to move downward, and the top inclined plane 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 rods 303. At this time, the grading component 3 at the top starts to repeat the above movement to increase the outlet of the grading port 302.

[0051] After the fluid enters the interior of the upper main pipe 401, since the opening and closing plate 4064 divides the upper main pipe 401 into upper and lower parts, the internal pressure of the upper part of the liquid gradually increases as the flow rate increases. The increase in the pipe internal pressure causes the second pressure rod 4061 to move to both sides. Under the rotational action 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 discharges liquid, the upper part pressure decreases, the opening and closing plate 4064 moves to both sides, the gap increases, and the flow rate increases. Thus, the constant pressure of the liquid flowing out at the top tank is achieved;

[0052] When an oil leakage occurs underwater and the pressure in the pipeline is greater than the threshold value, at this time, all the grading components 3 are at the farthest end of the moving position. The liquid at the lower pipe assembly 2 enters the interior of the pressure measurement chamber 107. The increase in the pressure at the pressure measurement chamber 107 causes the locking component 5 inside the pressure measurement pipe 108 to have a tendency to move upward rapidly. However, since the control plate 4053 applies pressure to the double side frame 504 at low pressure, the double side frame 504 cannot move. At this time, as the pressure inside the upper main pipe 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 reaching the farthest end, the resistance to the double side frame 504 is lost, and the double side frame 504 rapidly rises under the action of the liquid pressure inside the pressure measurement chamber 107, fixing the closing plate 503 inside the second valve 408 to achieve the closure of the pipeline. At this time, the liquid inside the pipeline cannot flow again, realizing safety protection.

[0053] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall 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), characterized in that: 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. The underwater safety valve for hydraulic production of offshore oil wells according to claim 1, characterized in that: 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 offshore oil wells according to claim 1, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in 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.

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