阅读说明：本技术 自控阀 (Self-control valve ) 是由 陆林峰 李�杰 马辉运 李玉飞 张�林 唐庚 罗伟 田璐 龚浩 王珏皓 陆小锋 于 2020-06-05 设计创作，主要内容包括：本申请公开了一种自控阀,属于油层钻井领域。所述自控阀呈管状空心结构,自控阀包括自控阀外壳,自控阀外壳内部自上而下依次设置有第一连接扣、球阀控制组件、中心杆和第二连接扣,其中,中心杆周侧设置有液压缸推动组件,球阀控制组件活动连接有球阀；自控阀设置于油管之间,并通过第一连接扣和第二连接扣分别将自控阀的顶部和底部与油管相连,油管设置于油层套管内,油管与油层套管之间存在环空压力；当液压缸推动组件受到的环空压力达到工作压力阈值时,液压缸推动组件带动中心杆向上运动,球阀控制组件受到中心杆的推动并向上运动；球阀控制组件向上运动时带动球阀翻转。本申请实施例的自控阀能够避免环空压力过高导致的油层套管挤毁问题。(The application discloses automatic control valve belongs to oil reservoir well drilling field. The automatic control valve is of a tubular hollow structure and comprises an automatic control valve shell, wherein a first connecting buckle, a ball valve control assembly, a central rod and a second connecting buckle are sequentially arranged in the automatic control valve shell from top to bottom, a hydraulic cylinder pushing assembly is arranged on the periphery of the central rod, and the ball valve control assembly is movably connected with a ball valve; the automatic control valve is arranged between oil pipes, the top and the bottom of the automatic control valve are respectively connected with the oil pipes through a first connecting buckle and a second connecting buckle, the oil pipes are arranged in the oil layer casing pipes, and annular pressure exists between the oil pipes and the oil layer casing pipes; when the annular pressure applied to the hydraulic cylinder pushing assembly reaches a working pressure threshold value, the hydraulic cylinder pushing assembly drives the central rod to move upwards, and the ball valve control assembly is pushed by the central rod and moves upwards; when the ball valve control assembly moves upwards, the ball valve is driven to overturn. The self-control valve of the embodiment of the application can avoid the problem of oil layer casing pipe collapse caused by overhigh annular pressure.)

1. The automatic control valve is characterized by being of a tubular hollow structure and comprising an automatic control valve shell, wherein a first connecting buckle, a ball valve control assembly, a central rod and a second connecting buckle are sequentially arranged in the automatic control valve shell from top to bottom, a hydraulic cylinder pushing assembly is arranged on the periphery of the central rod, and the ball valve control assembly is movably connected with a ball valve;

the automatic control valve is arranged between oil pipes, the top and the bottom of the automatic control valve are respectively connected with the oil pipes through the first connecting buckle and the second connecting buckle, the oil pipes are arranged in the oil layer casing pipe, and annular pressure exists between the oil pipes and the oil layer casing pipe;

when the annular pressure applied to the hydraulic cylinder pushing assembly reaches a working pressure threshold value, the hydraulic cylinder pushing assembly drives the central rod to move upwards, and the ball valve control assembly is pushed by the central rod to move upwards;

the ball valve control assembly drives the ball valve to turn over when moving upwards, and the ball valve is switched from a first state to a second state, wherein the ball valve is provided with a drift diameter and an orifice, and the flow area of the drift diameter is larger than that of the orifice; in the first state, the automatic control valve carries out gas-liquid transmission through the drift diameter; in the second state, the self-control valve performs the gas-liquid transfer through the orifice.

2. The self-controlling valve of claim 1, wherein the hydraulic cylinder pushing assembly comprises a hydraulic cylinder and a piston connected to each other;

the annular pressure is transmitted to the hydraulic cylinder through a pressure transmitting hole, and when the annular pressure borne by the hydraulic cylinder reaches the working pressure threshold value, the hydraulic cylinder drives the piston to move upwards, wherein the pressure transmitting hole is formed in the shell of the automatic control valve;

the piston is fixedly arranged on two sides of the central rod, and when the piston moves upwards, the central rod fixedly connected with the piston moves upwards.

3. The autonomous valve of claim 1, wherein a centerline of the drift diameter and a centerline of the orifice bore are perpendicular to each other.

4. The self-controlling valve of claim 3, wherein said ball valve control assembly comprises a ball valve pusher;

the ball valve push rod is provided with a 90-degree rotating stop, is used for bearing force and rotating by 90 degrees when the central rod moves upwards and driving the ball valve to turn by 90 degrees, and is switched from the first state to the second state.

5. The self-control valve according to claim 4, wherein when the ball valve is in the second state and the annular pressure is lower than the working pressure threshold, the hydraulic cylinder drives the piston to move downwards, the central rod fixedly connected with the piston moves downwards, and the ball valve push rod is driven to rotate; the ball valve is driven by the ball valve push rod to overturn and is switched from the second state to the first state.

6. The self-controlling valve according to any one of claims 1 to 5, wherein said ball valve control assembly further comprises a ball valve cylinder housing for receiving said ball valve;

the ball valve is turned over in a cavity of the ball valve cylinder sleeve.

7. The self-regulating valve according to any one of claims 1 to 5, wherein the working pressure threshold is less than an annulus pressure threshold, the annulus pressure threshold being the maximum sustainable pressure of the tubing.

8. The self-regulating valve of claim 7, wherein the annulus pressure threshold is determined from formation data and base data of the pay casing;

the stratum data comprises stratum water density, and the basic data of the oil layer casing pipe comprises oil layer casing pipe internal pressure resistance strength, oil layer casing pipe internal pressure resistance safety factor, annular protection liquid density and annular vertical depth.

9. The autonomous valve of claim 7 wherein the operating pressure threshold is determined based on the annulus pressure threshold and a vertical run-in depth of the autonomous valve.

10. The self-control valve according to any one of claims 1 to 5, wherein the throttling hole is used for throttling gas and liquid and generating the internal pressure of an oil pipe when the ball valve is in the second state;

when the ball valve is continuously in the second state, the self-control valve controls the annular pressure not to exceed the internal pressure of the oil pipe through the throttle hole.

Technical Field

The embodiment of the application relates to the field of oil reservoir drilling, in particular to an automatic control valve.

Background

In the process of natural gas exploration and development, the shut-in pressure of an ultrahigh pressure gas well (the formation pressure is more than or equal to 105MPa) is high, oil pipe leakage is easy to occur, the annular pressure of an oil sleeve annulus rises, and the oil sleeve is easy to crush due to the liquid column pressure of oil sleeve annulus protection liquid, so that the safety production of the gas well is seriously influenced.

In the related art, in order to avoid the oil pipe leakage problem, a method is adopted for injecting nitrogen into the hollow part of an oil sleeve ring to reduce the pressure of a liquid column so as to improve the safety coefficient of an oil layer casing pipe, but for an ultrahigh pressure gas well, the method still causes the risk that the oil layer casing pipe is crushed; in addition, a method for reducing the pressure of the underground throttler is adopted, but the highest working pressure environment of the underground throttler still does not reach the pressure environment of the ultrahigh-pressure gas well, and certain safety risks exist in the putting-in and working process of the underground throttler in the continuous operation process. Therefore, for the ultrahigh pressure gas well, the natural gas exploration and development process still faces the risks that the downhole tool cannot meet the production requirement and the operation of the ultrahigh pressure gas well under pressure cannot be avoided.

Disclosure of Invention

The embodiment of the application provides a self-control valve, can be used to solve among the related art because of the oil pipe seepage leads to the great problem that makes the reservoir casing to be crowded ruined of annular pressure. The technical scheme is as follows:

on one hand, the embodiment of the application provides an automatic control valve which is of a tubular hollow structure and comprises an automatic control valve shell, wherein a first connecting buckle, a ball valve control assembly, a central rod and a second connecting buckle are sequentially arranged in the automatic control valve shell from top to bottom, a hydraulic cylinder pushing assembly is arranged on the periphery of the central rod, and the ball valve control assembly is movably connected with a ball valve;

the automatic control valve is arranged between oil pipes, the top and the bottom of the automatic control valve are respectively connected with the oil pipes through the first connecting buckle and the second connecting buckle, the oil pipes are arranged in the oil layer casing pipe, and annular pressure exists between the oil pipes and the oil layer casing pipe;

when the annular pressure applied to the hydraulic cylinder pushing assembly reaches a working pressure threshold value, the hydraulic cylinder pushing assembly drives the central rod to move upwards, and the ball valve control assembly is pushed by the central rod to move upwards;

the ball valve control assembly drives the ball valve to turn over when moving upwards, and the ball valve is switched from a first state to a second state, wherein the ball valve is provided with a drift diameter and an orifice, and the flow area of the drift diameter is larger than that of the orifice; in the first state, the automatic control valve carries out gas-liquid transmission through the drift diameter; in the second state, the self-control valve performs the gas-liquid transfer through the orifice.

Optionally, the hydraulic cylinder pushing assembly comprises a hydraulic cylinder and a piston which are connected with each other;

the annular pressure is transmitted to the hydraulic cylinder through a pressure transmitting hole, and when the annular pressure borne by the hydraulic cylinder reaches the working pressure threshold value, the hydraulic cylinder drives the piston to move upwards, wherein the pressure transmitting hole is formed in the shell of the automatic control valve;

the piston is fixedly arranged on two sides of the central rod, and when the piston moves upwards, the central rod fixedly connected with the piston moves upwards.

Optionally, a center line of the drift diameter and a center line of the throttle hole are perpendicular to each other.

Optionally, the ball valve control assembly comprises a ball valve push rod;

the ball valve push rod is provided with a 90-degree rotating stop, is used for bearing force and rotating by 90 degrees when the central rod moves upwards and driving the ball valve to turn by 90 degrees, and is switched from the first state to the second state.

Optionally, when the ball valve is in the second state and the annular pressure is lower than the working pressure threshold, the hydraulic cylinder drives the piston to move downward, the central rod fixedly connected with the piston moves downward, and drives the ball valve push rod to rotate; the ball valve is driven by the ball valve push rod to overturn and is switched from the second state to the first state.

Optionally, the ball valve control assembly further comprises a ball valve cylinder sleeve, and the ball valve cylinder sleeve is used for accommodating the ball valve;

the ball valve is turned over in a cavity of the ball valve cylinder sleeve.

Optionally, the working pressure threshold is smaller than an annular pressure threshold, and the annular pressure threshold is the maximum tolerable pressure of the oil pipe.

Optionally, the annulus pressure threshold is determined according to formation data and base data of the reservoir casing;

the stratum data comprises stratum water density, and the basic data of the oil layer casing pipe comprises oil layer casing pipe internal pressure resistance strength, oil layer casing pipe internal pressure resistance safety factor, annular protection liquid density and annular vertical depth.

Optionally, the working pressure threshold is determined according to the annulus pressure threshold and the vertical penetration depth of the automatic control valve.

Optionally, the throttle hole is used for throttling gas and liquid and generating oil pipe internal pressure when the ball valve is in the second state;

when the ball valve is continuously in the second state, the self-control valve controls the annular pressure not to exceed the internal pressure of the oil pipe through the throttle hole.

In the embodiment of the application, an automatic control valve is provided, seepage takes place when oil pipe, annular pressure risees the problem, and annular pressure surpasss when pneumatic cylinder promotion subassembly operating pressure threshold value, pneumatic cylinder promotion subassembly motion drives well core rod upward movement, make ball valve control subassembly receive well core rod's promotion and upward movement, furthermore, drive the ball valve upset, the ball valve switches to the second state from first state, with the gas-liquid to the oil pipe throttle, with this control annular pressure does not exceed the oil pipe internal pressure after the throttle, protect oil reservoir casing's safety, can avoid the problem that the oil reservoir casing that leads to because annular pressure is too high is crowded, also can prevent the gas well underground gas hydrate and appear ice blocking problem simultaneously.

Drawings

Fig. 1 is a structural diagram of an initial state of a self-control valve according to an embodiment of the present application;

FIG. 2 illustrates an operation scenario of an autonomous valve provided by an embodiment of the present application;

FIG. 3 is a block diagram illustrating a ball valve rollover state of the self-control valve according to an embodiment of the present disclosure;

FIG. 4 is a block diagram illustrating a ball valve in a first state;

FIG. 5 is a block diagram illustrating the ball valve in a second state;

FIG. 6 is a block diagram illustrating an initial state of another self-control valve according to an embodiment of the present invention;

FIG. 7 is a block diagram of another self-controlling valve ball valve rollover state provided by an embodiment of the present application;

FIG. 8 is a flow chart of a method of use of a self-regulating valve operation provided by an embodiment of the present application.

Wherein the reference numerals in the drawings are explained as follows:

1: a housing of the automatic control valve; 2: a first connecting buckle; 3: a ball valve control assembly;

4: a center pole; 5: a second connecting buckle; 6: a hydraulic cylinder pushing assembly;

7: a ball valve; 8: an oil pipe; 9: an oil layer casing;

10: passing through; 11: an orifice; 12: a hydraulic cylinder;

13: a piston; 14: a ball valve push rod; 15: a ball valve cylinder liner;

16: and (6) pressure transfer holes.

With the foregoing drawings in mind, certain embodiments of the disclosure have been shown and described in more detail below. These drawings and written description are not intended to limit the scope of the disclosed concepts in any way, but rather to illustrate the concepts of the disclosure to those skilled in the art by reference to specific embodiments.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Reference herein to "a plurality" means two or more. "and/or" describes the association relationship of the associated objects, meaning that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

In the embodiments of the present application, the usage scenario of the automatic control valve is described by taking an ultrahigh pressure gas well usage scenario in an oil field production process as an example.

The shut-in pressure of the ultrahigh-pressure gas well is high, when an oil pipe leaks, the annular pressure can rise sharply, and in addition, the liquid column pressure of oil sleeve annular protection liquid can cause the oil layer casing to be damaged by squeezing, so that the high-pressure gas well is blown to the ground surface, and the safety production of the gas well is seriously influenced.

For the problems of the ultrahigh-pressure gas well, a method of injecting nitrogen into an oil sleeve annulus is generally adopted in the related art to reduce the hydrostatic column pressure so as to improve the safety coefficient of an oil layer casing, but for the gas well with overhigh wellhead pressure, the risk of crushing the oil layer casing still exists; in addition, a pressure reduction method of the downhole choke is adopted in the related technology, although the pressure reduction purpose is achieved, the highest working environment of the downhole choke is still limited, and certain safety risks exist in the operation process. Thus, the methods provided in the related art still face the safety risks of the downhole tools failing to meet production requirements and the operation of the ultra-high pressure gas well under pressure.

The embodiment of the application provides a self-control valve, can be used to solve among the related art because of the oil pipe seepage leads to the great problem that makes the reservoir casing to be crowded ruined of annular pressure. Referring to fig. 1 to 4, there are shown schematic structural views related to an automatic control valve provided in an exemplary embodiment of the present application.

As shown in fig. 1, the automatic control valve is a tubular hollow structure, and includes an automatic control valve housing 1, a first connecting buckle 2, a ball valve control assembly 3, a central rod 4 and a second connecting buckle 5 are sequentially arranged in the automatic control valve housing 1 from top to bottom, wherein a hydraulic cylinder pushing assembly 6 is arranged around the central rod 4, and the ball valve control assembly 3 is movably connected with a ball valve 7.

The shell 1 is used for isolating and protecting the automatic control valve; the first connecting buckle 2 and the second connecting buckle 5 are respectively used for connecting the top and the bottom of the automatic control valve with an oil pipe.

Fig. 2 shows an operation scenario of the automatic control valve according to the embodiment of the present application. In fig. 2, the automatic control valve is arranged between the oil pipes 8, namely, the upper part of the automatic control valve is connected with a section of oil pipe 8, and the lower part of the automatic control valve is also connected with a section of oil pipe 8; the top and the bottom of the automatic control valve are respectively connected with an oil pipe 8 by the automatic control valve through a first connecting buckle 2 and a second connecting buckle 5; in actual operation, the oil pipe 8 is arranged in the production casing 9, and an annular pressure exists between the oil pipe 8 and the production casing 9.

When the annular pressure between the oil pipe 8 and the oil layer casing pipe 9 is in a normal range, the risk that the oil layer casing pipe 9 is damaged by extrusion is small; when the oil pipe 8 leaks and the annular pressure increases sharply, the oil casing 9 is very easy to be squeezed to destroy liquid, in the self-control valve provided by the application, as shown in fig. 1, the annular pressure applied to the hydraulic cylinder pushing assembly 6 reaches the working pressure threshold value, the hydraulic cylinder pushing assembly 6 drives the central rod 4 to move upwards, and the ball valve control assembly 3 is pushed by the central rod 4 and moves upwards; further, when the ball valve control assembly 3 moves upwards, the ball valve 7 is driven to overturn, and the ball valve 7 is switched from the first state to the second state.

As shown in fig. 3, the configuration diagram of the automatic control valve when the ball valve 7 is in the second state corresponds to fig. 2, which corresponds to the configuration diagram of the automatic control valve when the ball valve 7 is in the first state.

As shown in fig. 4 and 5, the ball valve 7 is provided with a bore 10 and an orifice 11, and the flow area of the bore 10 is larger than the flow area of the orifice 11. As shown in fig. 4, in the first state, the self-control valve performs gas-liquid transmission through the drift diameter 10, and the flow area of the drift diameter 10 is large, so that the flow rate requirement during normal gas-liquid transmission can be met; as shown in fig. 5, in the second state, the automatic control valve performs gas-liquid transmission through the orifice 11, and since the flow area of the orifice 11 is small, the gas-liquid flow rate is reduced, so that the annular pressure is controlled not to exceed the pressure in the oil pipe after throttling, and the safety of the reservoir casing 9 is protected.

To sum up, in the embodiment of this application, an automatic control valve is provided, take place the seepage when oil pipe, annular pressure risees the problem, and annular pressure surpasss when pneumatic cylinder promotion subassembly operating pressure threshold value, pneumatic cylinder promotion subassembly motion drives well core rod upward movement, make ball valve control subassembly receive well core rod's promotion and upward movement, furthermore, drive the ball valve upset, the ball valve is from first state conversion to second state, with throttle to the gas-liquid in the oil pipe, with this control annular pressure no longer than the oil pipe internal pressure after the throttle, protect the oil reservoir casing's safety, can avoid the problem that the oil reservoir casing that leads to because annular pressure is too high is crowded and ruined promptly, also can prevent the gas well underground natural gas hydrate simultaneously and appear the ice-blocking problem.

Referring to fig. 6, there is shown a schematic structural view of a self-regulating valve provided in accordance with another exemplary embodiment of the present application.

In the embodiment of the present application, the principle that the hydraulic cylinder pushing assembly 6 drives the central rod 4 to move is realized by a hydraulic cylinder and a piston. As shown in fig. 6 and 7, the cylinder pushing assembly 6 includes a cylinder 12 and a piston 13 connected to each other.

In a possible implementation mode, a pressure transfer hole 16 is formed in the self-control valve shell 1, annular pressure existing between the oil pipe 8 and the oil layer casing pipe 9 is transferred to the hydraulic cylinder 12 through the pressure transfer hole 16, and when the annular pressure borne by the hydraulic cylinder 12 reaches the working pressure threshold of the hydraulic cylinder 12, the hydraulic cylinder 12 drives the piston 13 to move upwards; wherein, the piston 13 is fixedly arranged at two sides of the central rod 4, and when the piston 13 moves upwards, the central rod 4 fixedly connected with the piston 13 also moves upwards.

Further, as shown in fig. 6 and 7, in the present embodiment, the ball valve control assembly 3 includes a ball valve push rod 14. Optionally, the ball valve push rod 14 is provided with a 90-degree rotation stop, the ball valve push rod 14 is stressed and rotates 90 degrees when being used for the upward movement of the central rod 4, and drives the ball valve 7 to turn 90 degrees, and the ball valve 7 is switched from the first state to the second state. The first state corresponds to the structure diagram shown in fig. 6, and the second state corresponds to the structure diagram shown in fig. 7.

When the ball valve 7 is turned by 90 degrees so as to be switched from the first state to the second state, the ball valve 7 may be structurally designed such that the center line of the bore 10 and the center line of the orifice 11 are perpendicular to each other.

Through the upset of ball valve 7, carry out gas-liquid transmission through orifice 11 this moment, and then throttled the gas-liquid pressure in the oil pipe to this control annular space pressure does not exceed the oil pipe internal pressure after the throttle, protects oil layer sleeve's safety.

In one possible embodiment, the throttling hole 11 is used for throttling gas and liquid and generating the inner pressure of the oil pipe when the ball valve 7 is in the second state; when the ball valve 7 is continuously in the second state, the self-control valve controls the annular pressure not to exceed the internal pressure of the oil pipe 8 through the throttling hole 11.

Further, when the air pressure in the oil layer casing pipe is relieved, or after a period of production, the ball valve 7 is in a second state, and the annular pressure is lower than the working pressure threshold value, the hydraulic cylinder 12 drives the piston 13 to move downwards, the central rod 4 fixedly connected with the piston 13 moves downwards, and the ball valve push rod 14 is driven to rotate; the ball valve 7 is driven by the ball valve push rod 14 to overturn and is switched from the second state to the first state, and then the throttling function is relieved.

It should be noted that, because the hollow pressure in the production process changes irregularly, the automatic control valve can repeatedly realize the turning and rotation of the ball valve 7, so as to realize the automatic pressure control function of the automatic control valve.

Optionally, the ball valve control assembly 3 further includes a ball valve cylinder sleeve 15, the ball valve cylinder sleeve 15 is used for accommodating the ball valve 7, and the ball valve 7 is turned inside a cavity of the ball valve cylinder sleeve 15.

On the basis of the above embodiment, the embodiment of the application also discloses specific configurations of a hydraulic cylinder pushing assembly and a ball valve control assembly so as to further explain the principles of central rod movement and ball valve overturning; compared with the method for injecting nitrogen and setting the underground throttler in the related technology, the automatic control valve in the embodiment of the application realizes the movement of the piston through the stress induction of the hydraulic cylinder, then drives the central rod to move and the ball valve to overturn, finally realizes the automatic pressure control function of the automatic control valve, and avoids the problem that an oil layer casing is crushed due to overhigh annular pressure.

In the above embodiment, the hydraulic cylinder plays a key role in judging the magnitude of the received annular pressure. In each embodiment of the present application, the working pressure threshold of the hydraulic cylinder is a parameter set by combining the current device parameter and the actual production environment, and the requirement that the working pressure threshold is smaller than the annular pressure threshold needs to be satisfied. Therefore, based on the above embodiments, the present application also includes the contents of how to determine the working pressure threshold and the annulus pressure threshold, please refer to a flow chart of a method for operating and using the self-control valve shown in fig. 8.

Referring to FIG. 8, a flow chart of a method of using the self-regulating valve operation provided by an exemplary embodiment of the present application is shown.

Step 801, an annulus pressure threshold is calculated.

And the working pressure threshold is smaller than the annular pressure threshold, and the annular pressure threshold is the maximum bearable pressure of the oil pipe.

In the embodiment of the present application, formula 1 for calculating the annular pressure threshold is provided:

p_max1＝p_b/r+(p_d-p_a)g h₁*10^-3(formula 1)

Wherein p is_max1: the annular pressure threshold of the oil layer casing is MPa;

p_b: the internal pressure resistance of the oil layer casing is MPa;

r: the safety coefficient of the oil layer casing against internal pressure;

p_a: density of annular protection fluid in g/cm³；

p_d: density of formation water in g/cm³；

h₁: annulus vertical depth, m;

g: a constant of gravity.

As can be seen from equation 1, in the embodiment of the present application, the annular pressure threshold is determined based on the formation data and the base data of the casing. The stratum data comprise stratum water density, and the basic data of the oil layer casing comprise oil layer casing internal pressure resistance strength, oil layer casing internal pressure resistance safety factor, annular protection liquid density and annular vertical depth.

Step 802, calculating a working pressure threshold value according to the annulus pressure threshold value.

In one possible embodiment, the operating pressure threshold is determined based on the annulus pressure threshold and the vertical run-in depth of the autonomous valve.

In the embodiment of the present application, equation 2 for calculating the working pressure threshold is provided:

p_max2＝p_max1*S+p_agh₂*10^-3(formula 2)

Wherein p is_max2: the working pressure threshold of the hydraulic cylinder is MPa;

p_max1: the annular pressure threshold of the oil layer casing is MPa;

s: an annulus pressure threshold reduction factor;

p_a: density of annular protection fluid in g/cm³；

h₂: the vertical penetration depth of the automatic control valve is m;

g: a constant of gravity.

And step 803, the automatic control valve with the set working pressure threshold is put into the well.

In one possible embodiment, the self-controlled valve is arranged between the tubing between the upper part of the completion packer and the wellhead by means of a first and a second coupling link. In the well entering process, the initial state of the ball valve is the first state, and then the drift diameter in the pipe column is kept smooth.

In response to the annulus pressure exceeding the hydraulic cylinder working pressure threshold, the ball valve is flipped from the first state to a second state, step 804.

When the annular pressure rises, the annular pressure is transmitted to the hydraulic cylinder through the pressure transmitting hole; further, when the annular pressure exceeds the working pressure threshold value of the hydraulic cylinder, the hydraulic cylinder moves and drives the piston to move, then the ball valve push rod is driven to move upwards, the ball valve overturns 90 degrees, the ball valve overturns to the second state from the first state, throttling action is achieved, the annular pressure is controlled not to exceed the oil pipe pressure after throttling, and the safety of an oil layer casing is protected.

In response to the annulus pressure being below the hydraulic cylinder operating pressure threshold, the ball valve is returned from the second state to the first state, step 805.

When the annular pressure in the oil casing is relieved and the annular pressure is lower than the working pressure threshold of the hydraulic cylinder, the ball valve rotates reversely by 90 degrees, the ball valve returns to the first state, and the throttling effect is removed.

It should be noted that, because the air pressure in the production process changes irregularly, the self-control valve can repeatedly implement step 804 and step 805 to implement the automatic pressure control function of the self-control valve.

In one example, a natural gas well has a vertical depth of 7200m, a zone pressure of 130MPa, a zone temperature of 160 ℃, and a daily gas production of 30X 104m³D, oil pressure of a well head is 90MPa in production, and vertical depth h of an annulus is₁5000m, annular space protection fluid density p_aIs 1.0g/cm³Oil layerInternal pressure resistance p of casing_b94.4MPa, water density of stratum p_dIs 1.04g/cm³. Wherein the safety coefficient r of the internal pressure resistance of the oil layer casing is 1.25, and the annular pressure threshold value p is obtained by calculation_max1Is 77.48 MPa.

Further, an operating pressure threshold is calculated. Wherein the vertical penetration depth h of the automatic control valve₂Is 3000m, the reduction coefficient S of the annular pressure threshold value is 0.41, and the working pressure threshold value p is obtained through calculation_max2Is 61.4 MPa. When the annular pressure of the oil layer casing is larger than 61.4MPa, the hydraulic cylinder starts to work, and the ball valve is turned over, so that a gas-liquid column in the oil pipe generates a throttling effect, and the oil layer casing cannot be damaged by extrusion.

Furthermore, in the production process, when the annular pressure is reduced to be lower than 61.4MPa, the automatic control valve drives the ball valve to return to the initial state, namely, the ball valve returns to the first state from the second state, the throttling effect is removed, and the automatic control valve continues to keep the first state.

In another example, a natural gas well may have a vertical depth of 6800m, a zone pressure of 80MPa, a zone temperature of 120 deg.C, a wellhead oil pressure of 65MPa, a casing annulus pressure of 0MPa, and a daily water production of 6m³(d) daily gas production of 12X 104m³D annulus vertical depth h₁6000m, annular space protection fluid density p_aIs 1.0g/cm³Internal pressure resistance p of oil casing_b94.4MPa, water density of stratum p_dIs 1.04g/cm³. Wherein the safety coefficient r of the internal pressure resistance of the oil layer casing is 1.25, and the annular pressure threshold value p is obtained by calculation_max1Is 77.87 MPa. Further, the vertical penetration depth h of the automatic control valve₂The reduction coefficient S of the annular pressure threshold is 0.41, and the working pressure threshold p is obtained by calculation_max2Is 63.29 MPa. In the production process, the wellhead temperature is 26 ℃, the natural gas hydrate generation temperature is 31.7 ℃, and the ice blockage phenomenon caused by the natural gas hydrate is easy to occur near the wellhead.

In order to solve the problem of ice blockage, ground pressurization equipment can be adopted to pressurize the annular pressure of an oil layer sleeve to 35MPa, then a hydraulic cylinder works, a ball valve turns over 90 degrees, a throttling hole of the ball valve throttles a gas-liquid column in an oil pipe, the pressure of a well mouth after throttling is 20MPa, the production temperature of a natural gas hydrate is 24.2 ℃ at 20MPa, and then the problem of ice blockage caused by the natural gas hydrate in the well is avoided.

In the embodiment of the application, an operation and use method of the automatic control valve is provided, and the operation and use method is applied to the automatic control valve shown in each embodiment. The automatic control valve in each embodiment has the key effect of judging the size of the annular pressure borne by the hydraulic cylinder, the working pressure threshold value of the hydraulic cylinder is a parameter set by combining the current device parameter and the actual exploitation environment, and the requirement that the working pressure threshold value is smaller than the annular pressure threshold value needs to be met.

The above description is only exemplary of the present application and should not be taken as limiting, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.