阅读说明：本技术 一种井口安全阀液压控制系统 (Hydraulic control system for wellhead safety valve ) 是由 李友兴 张川 李中华 杜文波 杨超 宋学莲 于 2019-08-01 设计创作，主要内容包括：本发明公开了一种井口安全阀液压控制系统,包括油箱,油箱出油口通过截止阀连接有液压泵,液压泵通过单向阀分两路,一路连接减压阀进油口,减压阀出油口连接液控型换向阀的进油口,液控型换向阀出油口连接地面主安全阀,另一路为单向阀通过蓄能器连接井下安全阀,蓄能器与井下安全阀之间还连接有液控型换向阀,减压阀出油口分为两路,一路为减压阀连接加压阀,加压阀分别连接控制阀和高低压导阀,另一路为减压阀分别通过二位三通液控换向阀和二位三通液控换向阀连接地面主安全阀和地面翼安全阀,可适应高温、高压、爆炸等危险环境,带蓄能器自动补压,性能可靠；能自动且可靠地实现三种安全阀的逻辑顺序开井和顺序关井,保证井口的生产安全。(The invention discloses a hydraulic control system for a wellhead safety valve, which comprises an oil tank, wherein an oil outlet of the oil tank is connected with a hydraulic pump through a stop valve, the hydraulic pump is divided into two paths through a one-way valve, one path is connected with an oil inlet of a pressure reducing valve, an oil outlet of the pressure reducing valve is connected with an oil inlet of a hydraulic control type reversing valve, an oil outlet of the hydraulic control type reversing valve is connected with a ground main safety valve, the other path is the one-way valve which is connected with a downhole safety valve through an energy accumulator, a hydraulic control type reversing valve is further connected between the energy accumulator and the downhole safety valve, the oil outlet of the pressure reducing valve is divided into two paths, one path is the pressure reducing valve which is connected with a pressure valve, the pressure valve is respectively connected with, the device can adapt to dangerous environments such as high temperature, high pressure, explosion and the like, and is provided with an energy accumulator for automatic pressure compensation and reliable in performance; the three safety valves can be automatically and reliably opened and closed in a logic sequence, and the production safety of a wellhead is ensured.)

1. A hydraulic control system for a wellhead safety valve is characterized by comprising an oil tank (1), wherein an oil outlet of the oil tank (1) is connected with a hydraulic pump (5) through a stop valve B (6), the hydraulic pump (5) is divided into two paths through a check valve A (10), one path is connected with an oil inlet of a pressure reducing valve (28), an oil outlet of the pressure reducing valve (28) is connected with an oil inlet of a two-position three-way hydraulic control type reversing valve A (14), an oil outlet of the two-position three-way hydraulic control type reversing valve A (14) is connected with a ground main safety valve, the other path is that the check valve A (10) is connected with an underground safety valve through an energy accumulator A (29), a two-position three-way hydraulic control type reversing valve (12) is further connected between the energy accumulator A (29) and the underground safety valve, the oil outlet of the pressure reducing valve (28) is divided into two paths, the other path is connected, the other path is that a pressure reducing valve (28) is respectively connected with a main ground safety valve and a wing ground safety valve through a two-position three-way hydraulic control type reversing valve A (14) and a two-position three-way hydraulic control type reversing valve B (16).

2. A wellhead safety valve hydraulic control system according to claim 1, characterized in that the oil tank (1) is further connected with a hand pump (8) through a stop valve C (7), the hand pump (8) is further connected with a one-way valve (9), and the one-way valve (9) and the one-way valve A (10) are converged into one way.

3. A wellhead safety valve hydraulic control system according to claim 1, characterized in that the control valve (23) is connected with a fusible plug (17) through a one-way throttle valve (22), the fusible plug (17) is used for protecting pipelines, and the one-way throttle valve (22) is also connected with an emergency shut-off valve (18).

4. A wellhead safety valve hydraulic control system according to claim 3, characterized in that the single throttle valve (22) is also connected to the control valve (23) through a conduit.

5. A wellhead safety valve hydraulic control system according to claim 1, characterized in that the control valve (23) is also connected to the return port of the oil tank.

6. The wellhead safety valve hydraulic control system according to claim 1, characterized in that the oil outlet of the pressure valve (24) is divided into two paths through a control valve (23), one path is the oil outlet of the pressure valve (24) connected with the oil inlet of the control valve (23), the oil outlet of the control valve (23) is connected with the oil inlet of a two-position three-way manual reversing valve A (21), the oil outlet of the two-position three-way manual reversing valve A (21) is connected with a two-position three-way hydraulic reversing valve A (14), a two-position three-way manual reversing valve (19) is further connected between the two-position three-way manual reversing valve A (21) and the two-position three-way hydraulic reversing valve A (14), the two-position three-way manual reversing valve (19) is connected with a two-position three-way hydraulic reversing valve B (16), the two-position three-way hydraulic reversing valve B (16) is further connected with a two-position, a one-way throttle valve A (25) is arranged between the two-position three-way manual reversing valve A (21) and the two-position three-way hydraulic control reversing valve A (14); the other path is that a pressure valve (24) is connected with a control valve (23), and the control valve (23) is connected with a two-position three-way hydraulic control type reversing valve (12).

7. A wellhead safety valve hydraulic control system according to claim 6, characterized in that a two-position three-way manual reversing valve A (21) is further connected between the control valve (23) and the two-position three-way hydraulic reversing valve (12), the two-position three-way manual reversing valve A (21) is further connected with a two-position three-way hydraulic reversing valve C (20), a one-way throttle valve B (26) and an energy accumulator (27) are further sequentially connected between the control valve (23) and the two-position three-way hydraulic reversing valve (12), and the one-way throttle valve B (26) and the energy accumulator (27) are used for delaying oil return speed.

8. A wellhead safety valve hydraulic control system according to claim 1, characterized in that the control valve (23), the two-position three-way manual type change-over valve a (21), the two-position three-way hydraulic control type change-over valve C (20), the two-position three-way manual type change-over valve (19), the two-position three-way hydraulic control type change-over valve B (16), the two-position three-way hydraulic control type change-over valve a (14) and the two-position three-way hydraulic control type change-over valve (12) are further connected with a tank return port through oil pipes.

9. The wellhead safety valve hydraulic control system according to claim 1, characterized in that an overflow safety valve (11) is further connected between the oil inlet and the oil return port of the two-position three-way hydraulically controlled reversing valve (12), an overflow safety valve A (13) is further connected between the oil inlet and the oil return port of the two-position three-way hydraulically controlled reversing valve A (14), and an overflow safety valve B (15) is further connected between the oil inlet and the oil return port of the two-position three-way hydraulically controlled reversing valve B (16).

10. A wellhead safety valve hydraulic control system according to claim 1, characterized in that the oil tank is connected with two oil absorption filters (3) through two stop valves (2), the two oil absorption filters (3) are connected with two stop valves A (4), and the two stop valves A (4) are converged to one connecting stop valve B (6) to form a parallel oil transportation line.

Technical Field

The invention belongs to the technical field of hydraulic systems, and particularly relates to a hydraulic control system for a wellhead safety valve.

Background

The oil gas well head safety valve control system requires safety and reliability, and has higher control requirements for three safety valves, namely an underground safety valve, a ground main safety valve and a ground wing safety valve, and mainly shows that: the underground safety valve has higher control pressure between 10000psi and 20000psi, while the pressure of the ground main safety valve and the ground wing safety valve is about 3000psi generally, and the pressure difference of each level is larger; oil and gas well heads are generally in remote unattended areas, and serious accidents can be caused when the pressure of a production pipeline is too high or too low and even no human intervention is performed when a fire disaster happens; when the ground main valve is shut off, the ground wing valve is also shut off. Only when the ground main valve is opened, the ground wing valve can be opened, and a simple and reliable automatic control method is not available at present; three safety valve shut-in sequence requirements: firstly, closing a ground wing safety valve, closing a ground main safety valve in a delayed manner, and finally closing an underground safety valve in a delayed manner, wherein a simple, reliable and automatic control method does not exist at present; three safety valves are required in the well opening sequence: firstly opening the underground safety valve, then opening the ground main safety valve and finally opening the ground wing safety valve, otherwise, the production safety is also influenced if the underground safety valve cannot be completely opened; the production process requires that when the underground safety valve is closed, the ground main valve and the ground wing valve must be closed, and only when the underground safety valve is opened, the ground main valve and the ground wing valve can be opened, so that no simple and reliable automatic control method exists at present.

Disclosure of Invention

The invention aims to provide a hydraulic control system for a wellhead safety valve, which solves the problems of poor reliability, complex structure, incapability of automatic control and limited use environment in the prior art.

The technical scheme includes that a hydraulic control system of a wellhead safety valve comprises an oil tank, an oil outlet of the oil tank is connected with a hydraulic pump through a stop valve B, the hydraulic pump is divided into two paths through a one-way valve A, one path is connected with an oil inlet of a pressure reducing valve, an oil outlet of the pressure reducing valve is connected with an oil inlet of a hydraulic control type reversing valve A, an oil outlet of a two-position three-way hydraulic control type reversing valve A is connected with a ground main safety valve, the other path is that the one-way valve A is connected with an underground safety valve through an energy accumulator A, a two-position three-way hydraulic control type reversing valve is further connected between the energy accumulator A and the underground safety valve, the oil outlet of the pressure reducing valve is divided into two paths, the one path is that the pressure reducing valve is connected with a pressure valve, the pressure valve is.

The invention is also characterized in that:

the oil tank is also connected with a hand pump through a stop valve C, the hand pump is also connected with a one-way valve, and the one-way valve A are converged into one path;

the control valve is connected with an fusible plug through a one-way throttle valve, the fusible plug is used for protecting a pipeline, and the one-way throttle valve is also connected with an emergency shut-off valve;

the single throttle valve is also connected with a control valve through an oil guide pipe;

the control valve is also connected with an oil return port of the oil tank;

the oil outlet of the pressure valve is divided into two paths through a control valve, one path is that the oil outlet of the pressure valve is connected with the oil inlet of the control valve, the oil outlet of the control valve is connected with the oil inlet of a two-position three-way manual reversing valve A, the oil outlet of the two-position three-way manual reversing valve A is connected with a liquid control type reversing valve A, a two-position three-way manual reversing valve is further connected between the two-position three-way manual reversing valve A and the liquid control type reversing valve A, the two-position three-way manual reversing valve is connected with a two-position three-way liquid control type reversing valve B, the two-position three-way liquid control type reversing valve B is further connected with the two-position three-way manual reversing valve through an oil return pipe to form an oil return path; the other path is that a pressure valve is connected with a control valve, and the control valve is connected with a two-position three-way hydraulic control type reversing valve;

the control valve is connected with a two-position three-way hydraulic control type reversing valve, a two-position three-way manual type reversing valve A is connected with a two-position three-way hydraulic control type reversing valve C, a one-way throttle valve B and an energy accumulator are sequentially connected between the control valve and the two-position three-way hydraulic control type reversing valve, and the one-way throttle valve B and the energy accumulator are used for delaying oil return speed;

the control valve, the two-position three-way manual reversing valve A, the two-position three-way hydraulic reversing valve C, the two-position three-way manual reversing valve, the two-position three-way hydraulic reversing valve B, the two-position three-way hydraulic reversing valve A and the two-position three-way hydraulic reversing valve are also connected with an oil tank return port through oil pipes;

an overflow safety valve A is also connected between the oil inlet and the oil return port of the two-position three-way hydraulic control type reversing valve A, and an overflow safety valve B is also connected between the oil inlet and the oil return port of the two-position three-way hydraulic control type reversing valve B;

the oil tank is respectively connected with two oil absorption filters through two stop valves, the two oil absorption filters are respectively connected with two stop valves A, and the two stop valves A converge to one path to be connected with a stop valve B to form a parallel oil transportation line;

the invention has the beneficial effects that:

the hydraulic control system of the wellhead safety valve can adapt to dangerous environments such as high temperature, high pressure and explosion, and is provided with the energy accumulator for automatic pressure compensation and reliable in performance; the logical sequence well opening and sequential well closing of the three safety valves can be automatically and reliably realized, and the production safety of a well head is ensured; the system has the closing function of the high-low pressure pilot valve, and automatically closes the ground main safety valve and the ground wing safety valve when the pressure fluctuation of the oil-gas pipeline is large; the emergency shutdown function is provided, the shutdown of the three safety valves is completed by one-time operation on the escape road, and the operation is quick, simple and reliable. And a redundant oil way is arranged to ensure the reliability of the system.

Drawings

Fig. 1 is a schematic diagram of a wellhead safety valve hydraulic control system according to the invention.

In the figure, 1, an oil tank, 2, a stop valve, 3, an oil absorption filter, 4, a stop valve A, 5, a hydraulic pump, 6, a stop valve B, 7, a stop valve C, 8, a hand pump, 9, a one-way valve, 10, a one-way valve A, 11, an overflow safety valve, 12, a two-position three-way hydraulic control type reversing valve, 13, an overflow safety valve A, 14, a two-position three-way hydraulic control type reversing valve A, 15, an overflow safety valve B, 16, a two-position three-way hydraulic control type reversing valve B, 17, a fusible plug, 18, an emergency shut-off valve, 19, a two-position three-way manual type reversing valve, 20, a two-position three-way hydraulic control type reversing valve C, 21, a two-position three-way manual type reversing valve A, 22, a one-way throttle valve, 23, a control valve, 24, a pressurizing valve, 25, a one-way throttle valve A, 26.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention provides a hydraulic control system for a wellhead safety valve, which comprises an oil tank 1 as shown in figure 1, wherein the oil tank is respectively connected with two oil absorption filters 3 through two stop valves 2, the two oil absorption filters 3 are respectively connected with two stop valves A4, and then the two stop valves A4 converge to one path to be connected with a stop valve B6 to form a parallel oil transmission line;

an oil outlet of an oil tank 1 is connected with a hydraulic pump 5 through a stop valve B6, the hydraulic pump 5 is divided into two paths through a one-way valve A10, one path is connected with an oil inlet of a pressure reducing valve 28, an oil outlet of the pressure reducing valve 28 is connected with an oil inlet of a two-position three-way hydraulic control type reversing valve A14, an oil outlet of a two-position three-way hydraulic control type reversing valve A14 is connected with a ground main safety valve, the other path is a one-way valve A10 connected with a downhole safety valve through an energy accumulator A29, a two-position three-way hydraulic control type reversing valve 12 is further connected between the energy accumulator A29 and the downhole safety valve, the oil outlet of the pressure reducing valve 28 is divided into two paths, one path is the pressure reducing valve 28 connected with a pressurizing valve 24, the pressurizing valve 24 is respectively connected with a control valve 23 and a high-low pressure pilot valve, the other path is the, the fusible plug 17 is used for protecting pipelines, the one-way throttle valve 22 is also connected with an emergency shut-off valve 18, and the one-way throttle valve 22 is also connected with a control valve 23 through an oil guide pipe;

the oil tank 1 is also connected with a hand pump 8 through a stop valve C7, the hand pump 8 is also connected with a one-way valve 9, and the one-way valve 9 and the one-way valve A10 are converged into one path;

an oil outlet of a pressurizing valve 24 is divided into two paths through a control valve 23, one path is that the oil outlet of the pressurizing valve 24 is connected with an oil inlet of the control valve 23, the oil outlet of the control valve 23 is connected with an oil inlet of a two-position three-way manual reversing valve A21, an oil outlet of a two-position three-way manual reversing valve A21 is connected with a two-position three-way hydraulic reversing valve A14, a two-position three-way manual reversing valve 19 is further connected between the two-position three-way manual reversing valve A21 and a two-position three-way hydraulic reversing valve A14, the two-position three-way manual reversing valve 19 is connected with a two-position three-way hydraulic reversing valve B16, the two-position three-way hydraulic reversing valve B16 is further connected with the two-position three-way manual reversing valve 19 through an oil return pipe to form an oil return path, and a one-way; the other path is that a pressure valve 24 is connected with a control valve 23, and the control valve 23 is connected with a two-position three-way hydraulic control type reversing valve 12;

a two-position three-way manual reversing valve A21 is further connected between the control valve 23 and the two-position three-way hydraulic reversing valve 12, the two-position three-way manual reversing valve A21 is further connected with a two-position three-way hydraulic reversing valve C20, a one-way throttle valve B26 and an energy accumulator 27 are further sequentially connected between the control valve 23 and the two-position three-way hydraulic reversing valve 12, and the one-way throttle valve B26 and the energy accumulator 27 are used for delaying oil return speed;

the control valve 23, the two-position three-way manual reversing valve A21, the two-position three-way hydraulic reversing valve C20, the two-position three-way manual reversing valve 19, the two-position three-way hydraulic reversing valve B16, the two-position three-way hydraulic reversing valve A14 and the two-position three-way hydraulic reversing valve 12 are also connected with an oil tank return port through oil pipes;

an overflow safety valve 11 is further connected between the oil inlet and the oil return port of the two-position three-way hydraulic control type reversing valve 12, an overflow safety valve A13 is further connected between the oil inlet and the oil return port of the two-position three-way hydraulic control type reversing valve A14, and an overflow safety valve B15 is further connected between the oil inlet and the oil return port of the two-position three-way hydraulic control type reversing valve B16.

The advantages of the invention are explained by the working principle:

as shown in fig. 1, after passing through a stop valve 2, a stop valve a4 and an oil suction filter 3 from an oil tank 1, hydraulic oil enters a hydraulic pump 5 through a stop valve B6, the pump 5 increases the pressure of the hydraulic oil and divides the hydraulic oil into two paths through a check valve a10, and one path is used for supplying oil to a ground main safety valve and a ground wing safety valve through a pressure reducing valve 28. The other way enters an accumulator A29 to charge the accumulator and supply oil for opening the downhole safety valve, and when the pressure is too high, the hydraulic oil returns to the tank through an overflow safety valve 11. After the accumulator A29 is full of hydraulic oil, it can be used as an auxiliary power source to provide continuous pressure for the system, ensuring normal function, at this time, the pump can be stopped until the accumulator pressure is less than the motor, and the pump can be started again.

The hydraulic oil is divided into two paths after passing through the pressure reducing valve 28, and one path of the hydraulic oil is used as pilot oil to supply oil for the control valve 23 and the high-low pressure pilot valve through the pressure reducing valve 24. The other path of the hydraulic oil is supplied to a two-position three-way hydraulic control type reversing valve A14 and a two-position three-way hydraulic control type reversing valve B16 which supply oil to a ground main safety valve and a ground wing safety valve, and when the pressure is too high, the hydraulic oil returns to the oil tank through an overflow safety valve A13 and an overflow safety valve B15;

logical well opening of three safety valves: the pressure oil enters a two-position three-way manual reversing valve 23 through a pressure reducing valve 24, the two-position three-way manual reversing valve manually controls a downhole safety valve, and when a handle of the two-position three-way manual reversing valve 23 is manually pulled, A is enabled₁Mouth and B₁The port is communicated and passes through the B of the two-position three-way manual reversing valve 23₁The post-port pilot oil is divided into four paths: one path of hydraulic control port D flows through the one-way throttle valve 22 and then flows back to the two-position three-way manual reversing valve 23₁Keeping the two-position three-way manual reversing valve 23 in an open state; one path of the oil supply system II supplies oil to a two-position three-way manual reversing valve A21 for controlling a ground safety main valve; d for III one-way feed two-position three-way hydraulic control type reversing valve C20₇One way of the IV is directly led to the D of the two-position three-way hydraulic control type reversing valve 12 through a one-way throttle valve B26₆The port pushes the valve core of the two-position three-way hydraulic control type reversing valve 12 to act, so that the oil port A of the valve core is enabled to₆And B₆And if the hydraulic oil is communicated, the hydraulic oil flowing out of the hydraulic pump 5 is led to a downhole safety valve to be opened. Only when the control valve 23 of the downhole safety valve is opened, the pilot oil can enter the two-position three-way manual reversing valve A21 of the surface main safety valve, and the manual opening makes A open₂Mouth and B₂The port is communicated, and the pilot oil enters two positions through a one-way throttle valve A25Hydraulic control port D of three-way hydraulic control type reversing valve A14₅The valve core of the two-position three-way hydraulic control type reversing valve A14 is pushed to act, so that the oil port A of the valve core is enabled to be₅And B₅And the hydraulic oil is communicated with a main ground safety valve to open. Similarly, when the high-low pressure pilot valve is normal, only the two-position three-way manual reversing valve a21 of the ground main safety valve is opened, and the pilot oil can open the ground safety valve through the two-position three-way manual reversing valve 19. Accordingly, the sequential opening logic function of three safety valves is realized: firstly, opening the underground safety valve to open the main ground safety valve; the ground wing safety valve can be opened after the ground main safety valve is opened.

Three safety valve logic shut-in wells: when the manual control valve 23 of the downhole safety valve is manually closed in a state where all three safety valves are open, B₁Mouth and oil drainage port C₁The pilot oil flows back to the oil tank. D of two-position three-way hydraulic control type reversing valve C20 communicated with D₇When the hydraulic oil returns, the valve core of the two-position three-way hydraulic control reversing valve C20 is reset by the spring force B₇And C₇D of two-position three-way manual reversing valve A21 with communicated ports₂The port pilot oil directly returns to the oil tank through a two-position three-way hydraulic control type reversing valve C20, and the ground main safety valve controls the two-position three-way hydraulic control type reversing valve A21 to be closed under the action of a spring. An oil supply port A of the two-position three-way manual reversing valve 19 communicated with the two-position three-way manual reversing valve A21 at the same time₃And then the oil is returned, and the two-position three-way manual reversing valve 19 next to the ground wing safety valve is also closed. The manual control valve 23, the two-position three-way manual reversing valve A21 and the two-position three-way manual reversing valve 19 for controlling the three safety valves are closed at intervals in a short time (compared with the condition that the two-position three-way manual reversing valve A21 and the two-position three-way manual reversing valve B16 can be closed simultaneously), and the two-position three-way hydraulic reversing valve 12, the two-position three-way hydraulic reversing valve A14 and the two-position three-way hydraulic reversing valve B16 are sequentially and correspondingly controlled to be reversed, so that the corresponding underground safety valve. The two-position three-way manual reversing valve 19 is connected with the two-position three-way hydraulic control reversing valve B16 only through a pipeline, the direct oil return speed is the fastest, and therefore the wing safety valve is closed firstly; a one-way throttle valve A is arranged between the two-position three-way manual reversing valve A21 and the two-position three-way hydraulic control reversing valve A1425, the oil return process is slowed down through throttling, the oil return time is longer than that of direct oil return of the two-position three-way hydraulic control type reversing valve B16, and therefore the main safety valve is closed behind the wing safety valve; the control valve 23 is connected with the two-position three-way hydraulic control type reversing valve 12 through the one-way throttle valve B26 and the energy accumulator 27, the oil return speed is slow through throttling, and the energy accumulator 27 replenishes hydraulic oil into the pipe to further delay the oil return process, so that the underground safety valve is closed after the main safety valve. In conclusion, when the well is shut down, the ground wing safety valve is firstly closed, then the ground main safety valve is closed, and finally the underground safety valve is closed, so that the logical well shut-down sequence of the three safety valves is realized.

When the three safety valves are opened, the handle of the two-position three-way manual reversing valve A21 of the ground main safety valve is only pulled manually to close the three-position three-way manual reversing valve A21, and then the three-position three-way manual reversing valve B is pulled manually₂Mouth and C₂The port is communicated with a pilot oil return tank, pilot oil of the two-position three-way manual reversing valve 19 also returns to the tank, and the two-position three-way manual reversing valve 19 is closed under the action of the self spring force. The two-position three-way manual reversing valve 19 is connected with the two-position three-way hydraulic control reversing valve B16 only through a pipeline, the direct oil return speed is high, and therefore the wing safety valve is closed firstly; the two-position three-way manual reversing valve A21 and the two-position three-way hydraulic control reversing valve A14 are connected through a one-way throttle valve A25, the process of oil return is slowed down through throttling, the oil return time is longer than the direct oil return of the two-position three-way hydraulic control reversing valve B16, and therefore the main safety valve is closed behind the wing safety valve. At the moment, the underground safety valve is still in an open state, and the two ground safety valves are closed according to a logic sequence.

And (3) automatically closing the well when the temperature rises in case of fire: when fire occurs at the well mouth, the temperature of the oil (gas) production tree rises, the fusible plug 17 arranged on the oil (gas) production tree is melted, so that the oil circuit of the circuit is conducted, the hydraulic oil flows out of the hydraulic oil pipe, the pressure of the hydraulic oil is reduced, the flow is reduced, the one-way throttle valve 22 prevents the supplement of the hydraulic oil at the front end of the valve, and the supplement of the hydraulic oil at the front end of the valve is along with the D of the control valve 23₁The hydraulic oil flows out, the spring force of the control valve 23 is not balanced enough, the control valve 23 is closed under the action of the spring force, and the oil supply port A₁Opening of the mouth, B₁Mouth and C₁The ports are communicated with each other, the hydraulic oil returns to the oil tank, and three safety valves are arrangedAnd the valves are closed in sequence according to a logic sequence, so that the loss of the oil-gas well is reduced, and the production safety is ensured.

Emergency shut-in: when the emergency situations of leakage, sudden pressure rise, incapability of control and the like occur, field operators evacuate rapidly, emergency shutoff is arranged on an evacuation escape path, the emergency shutoff valve 18 is opened by the operators, hydraulic oil flows out of the pipe, the pressure reduction flow is less, and the three safety valves are repeatedly closed sequentially according to a logic sequence.

Automatically closing the ground main and wing safety valves during pressure fluctuation: the other path of hydraulic oil is supplied to the high-low pressure pilot valve after being decompressed by the decompression valve 24, when the pressure of the production pipeline is in a normal range, the hydraulic oil can return from the high-low pressure pilot valve and reach A of the two-position three-way hydraulic control type reversing valve C20₇D of two-position three-way hydraulic control type reversing valve C20 during normal work₇Is provided with a pressure oil supply A₇Mouth and B₇The opening is communicated, so that the return oil of the high-low pressure pilot valve acts on D of the two-position three-way manual reversing valve A21₂The two-position three-way manual reversing valve A21 is ensured to be kept in an opening state A₂And B₂And conducting. When the pressure fluctuation of the production pipeline is large and is not in the normal range, the high-low pressure pilot valve is closed, and the return oil of the high-low pressure pilot valve cannot act on the D of the two-position three-way manual reversing valve A21₂The mouth keeping it open or C₂And B₂When the production pressure is switched on, the two-position three-way manual reversing valve A21 automatically resets under the action of the self spring force when the production pressure has large fluctuation, so that the two-position three-way hydraulic reversing valve A14 starts to reset, the two-position three-way manual reversing valve 19 is closed due to linkage, and the two-position three-way hydraulic reversing valve B16 is closed, and because the oil return time of the two-position three-way hydraulic reversing valve A14 is different from that of the two-position three-way hydraulic reversing valve B16, the ground wing safety valve controlled by the two-position three-way hydraulic reversing valve B16 is firstly closed with the ground main safety valve controlled by the two-position three-way hydraulic reversing valve A14.

Replacing the filter element on line without stopping the machine: the system sets up one and uses one and be equipped with two oil absorption filter circuit, when the work filter core need be changed, closes the removable filter core of stop valve 2 and stop valve A4, opens the stop valve of reserve oil absorption return circuit simultaneously, does not shut down and does not influence the normal work of system.

Manual emergency oil source: the stop valve C7, the hand pump 8 and the one-way valve 9 are connected with the hydraulic pump 5 in parallel to serve as a standby pump oil way, and the hand pump 8 can be operated to serve as an emergency oil source under the condition that the system is powered off.