CN220015125U - Differential pressure control type one-way valve and tool pipe string - Google Patents

Abstract

The utility model provides a differential pressure control type one-way valve and a tool pipe string, wherein the one-way valve comprises a sleeve, a piston, a valve clack mechanism and a first locking mechanism, the piston is arranged in the sleeve in a penetrating way, a gap is formed between the piston and the sleeve, a first flange is arranged on the outer wall of the piston, the gap is divided into a first chamber and a second chamber by the first flange, and the piston can axially move to control the one-way valve to be opened and closed; the first locking mechanism is arranged in the second chamber and can lock the piston at the lowest end to keep the one-way valve open; the valve clack mechanism is arranged below the first locking mechanism, can be limited between the piston and the sleeve by the piston when the one-way valve is opened, and can block and close the one-way valve at the lower end of the piston after the piston moves upwards; the check valve solves the problem of plugging in the oil pipe in the conventional oil pipe with fracturing, can realize state switching through oil jacket pressure difference, can realize reverse circulation operation function, can keep the check valve open by simple operation, and ensures safe and efficient operation with pressure.

Description

Differential pressure control type one-way valve and tool pipe string

Technical Field

The utility model relates to the technical field of oil and gas well drilling downhole tools, in particular to a differential pressure control type one-way valve and a tool pipe string.

Background

At present, a high-inclination well of an oil well in a long-distance oil-producing area is usually subjected to fracturing construction by adopting a bottom-seal hydraulic jet fracturing tool technology, and is transmitted through a conventional oil pipe, a drilling tool can be adjusted to the next-layer section for construction after each-layer section is constructed by closing the well, open-flow and backwashing, the construction efficiency is seriously restricted, and the flow-back fluid is high in pulling and conveying and treatment cost. After a section of conventional oil pipe single-bottom sealing hydraulic spraying fracturing process is fractured, a drilling tool can be adjusted to the next section of the oil pipe under pressure to continue construction without discharging and backwashing, the defect of the original bottom sealing hydraulic spraying fracturing tool technology can be effectively overcome through continuous high-efficiency fracturing construction under pressure, the conventional oil pipe single-bottom sealing hydraulic spraying fracturing construction is realized, the prior art cannot realize that a hydraulic working machine is not used for carrying out hydraulic dragging and layer changing, and one of the main problems is that sealing and blocking in the oil pipe cannot be safely and effectively realized before the hydraulic dragging and layer changing is implemented after the fracturing of the section.

Disclosure of Invention

The present utility model aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the purposes of the present utility model is to provide a differential pressure control type one-way valve and a tool pipe string, so as to solve the technical problem that sealing and plugging in an oil pipe cannot be safely and effectively achieved in the implementation process of a conventional oil pipe pressurized dragging hydraulic jet fracturing process.

In order to achieve the above object, according to an aspect of the present utility model, there is provided a differential pressure control type check valve, which may include a sleeve, a piston, a valve flap mechanism, and a first locking mechanism, wherein the piston may be penetrated in the sleeve, a gap may be formed between the piston and the sleeve, a first flange may be provided on an outer wall of the piston, the first flange may be attached to an inner wall of the sleeve, the first flange may divide the gap between the piston and the sleeve into a first chamber located above and a second chamber located below, and the piston may move up and down in an axial direction of the sleeve under a differential pressure of the first chamber and the second chamber to control the check valve to be opened or closed; a first locking mechanism can be arranged in the second chamber, and the first locking mechanism can lock the piston at the lowest end of the moving stroke so as to keep the one-way valve in an open state; the valve clack mechanism can be arranged below the first locking mechanism, can be limited in a gap between the piston and the sleeve by the piston in the opening state of the one-way valve, and can block the lower end of the piston after the piston moves upwards so as to close the one-way valve.

Optionally, a second flange may be further provided on the outer wall of the piston, and the second flange may be located below the first flange; the first locking mechanism can comprise a first locking piece and an adjusting ring, the first locking piece can be sleeved on the piston, a first pawl can be formed at the upper end of the first locking piece and can be clamped with the second flange so as to lock the piston at the lowest end of the moving stroke; the adjusting ring can be sleeved on the first locking piece, and the adjusting ring can adjust the locking force of the first locking piece to the piston.

Alternatively, the valve clack mechanism may include a valve clack and an elastic member, one end of the elastic member may be fixedly connected to the inner wall of the sleeve, the other end of the elastic member may be fixedly connected to the valve clack, and the valve clack may be turned under the action of the elastic force of the elastic member to block the lower end of the piston.

Optionally, a plurality of first side holes may be formed on a side wall of the piston, and the first side holes may communicate the first chamber with the inner cavity of the piston; the side wall of the sleeve can be provided with a plurality of second side holes, and the second side holes can be used for communicating the second chamber with the outer wall of the sleeve; the pressure in the first chamber can be adjusted by changing the pressure of the inner chamber of the piston and the pressure in the second chamber can be adjusted by changing the oil jacket annulus pressure outside the sleeve.

Optionally, a water hole screw and a filter screen may be installed in the second side hole, the water hole screw may plug the second side hole, and the filter screen may filter the fluid passing through the second side hole.

Optionally, the check valve may further include a sand control ring, the sand control ring may be sleeved on the piston and located at the first side hole, and a plurality of line cutting slits may be formed on the sand control ring, and the sand control ring may be capable of filtering fluid passing through the first side hole.

Optionally, the check valve may further include an upper joint fixedly connected to an upper end of the sleeve, and a second locking mechanism capable of being placed in the upper joint and abutting against an upper end of the piston in an opened state of the check valve, and limiting the piston to a lowermost end of a moving stroke to prevent the check valve from being closed.

Optionally, the second locking mechanism may include a second locking member and a valve core, and a second pawl may be formed at an upper end of the second locking member, where the second pawl may be engaged with a slot on an inner wall of the upper joint, so as to fix the second locking member and limit the piston from ascending; the valve core can be arranged in the second locking piece, and can allow fluid below the second locking piece to flow upwards and prevent fluid above the second locking piece from flowing downwards.

Optionally, the one-way valve may further include a lower connector, the lower connector may be mounted at a lower end of the sleeve, and an inner cavity of the lower connector is in communication with an inner cavity of the piston.

Another aspect of the utility model provides a tool string that may include a differential pressure controlled one-way valve as described above.

Compared with the prior art, the utility model has the beneficial effects that at least one of the following contents is included:

the differential pressure control type one-way valve solves the problem of plugging in an oil pipe in the implementation process of a conventional oil pipe pressurized dragging hydraulic jet fracturing process, can realize free switching of plugging or opening fracturing states through simple operation of manufacturing oil jacket differential pressure, has a simple operation method, ensures safer and more efficient pressurized operation, has the function of realizing reverse circulation and other operations, and can be in an open state through simple operation when a pipe column is required to perform reverse circulation and other operations, so that the construction mode is more flexible.

Drawings

The foregoing and other objects and/or features of the utility model will become more apparent from the following description taken in conjunction with the accompanying drawings in which:

fig. 1 illustrates an open state schematic diagram of a differential pressure control type check valve according to an exemplary embodiment of the present utility model.

Fig. 2 is a schematic diagram showing a closed state of a differential pressure control type check valve according to an exemplary embodiment of the present utility model.

Fig. 3 shows a schematic view of a second locking mechanism in a differential pressure controlled check valve according to an exemplary embodiment of the present utility model.

Fig. 4 is a schematic view showing a state in which the differential pressure control type check valve is kept locked open during the tripping process according to an exemplary embodiment of the present utility model.

Reference numerals illustrate:

1. sleeve, 11, first chamber, 12, second chamber, 13, second side hole, 131, water eye screw, 132, screen, 2, piston, 21, first flange, 22, second flange, 23, first side hole, 3, first locking mechanism, 31, first locking piece, 311, first pawl, 32, adjusting ring, 4, clack mechanism, 41, clack, 42, elastic piece, 5, sand control ring, 6, upper joint, 7, second locking mechanism, 71, second locking piece, 711, second pawl, 72, valve core, 8, lower joint.

Detailed Description

Hereinafter, the differential pressure control type check valve and the tool string of the present utility model will be described in detail with reference to exemplary embodiments.

In the description of the present utility model, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

The high-inclination well is usually subjected to fracturing construction by adopting a bottom-seal hydraulic jet fracturing tool technology, and is transported through a conventional oil pipe, a drilling tool can be adjusted to the next interval for construction after each interval is subjected to construction by well closing, open flow and back flushing, so that the construction efficiency is seriously restricted, and the flow-back fluid is high in pulling, transporting and treating cost. After a section of conventional oil pipe single-bottom sealing hydraulic spraying fracturing process is fractured, a drilling tool can be adjusted to the next section of the oil pipe under pressure to continue construction without discharging and backwashing, the defects of the original bottom sealing hydraulic spraying fracturing tool technology can be effectively overcome through continuous high-efficiency fracturing construction under pressure, but the mode of conventional oil pipe under pressure hydraulic spraying fracturing construction cannot be adopted, the purpose that a pressurized working machine is not used for carrying out pressurized dragging and layer changing is not achieved, and one of the main problems is that sealing and plugging in the oil pipe cannot be safely and effectively achieved before pressurized dragging and layer changing are implemented after the section of the oil pipe is fractured.

Based on the above, the utility model provides a differential pressure control type one-way valve and a tool pipe string, wherein the one-way valve can comprise a sleeve, a piston, a valve clack mechanism and a first locking mechanism, the piston can be arranged in the sleeve in a penetrating way, a gap can be formed between the piston and the sleeve, a first flange can be arranged on the outer wall of the piston, the first flange can be attached to the inner wall of the sleeve, the gap between the piston and the sleeve can be divided into a first chamber positioned above and a second chamber positioned below by the first flange, and the piston can move up and down along the axial direction of the sleeve under the differential pressure action of the first chamber and the second chamber so as to control the one-way valve to be opened or closed; a first locking mechanism can be arranged in the second chamber, and the first locking mechanism can lock the piston at the lowest end of the moving stroke so as to keep the one-way valve in an open state; the valve clack mechanism can be arranged below the first locking mechanism, can be limited in a gap between the piston and the sleeve by the piston in the opening state of the one-way valve, and can block the lower end of the piston after the piston moves upwards so as to close the one-way valve.

The differential pressure control type one-way valve solves the problem of plugging in an oil pipe in the implementation process of a conventional oil pipe pressurized dragging hydraulic jet fracturing process, can realize free switching of plugging or opening fracturing states through simple operation of manufacturing oil jacket differential pressure, has a simple operation method, ensures safer and more efficient pressurized operation, has the function of realizing reverse circulation and other operations, and can be in an open state through simple operation when a pipe column is required to perform reverse circulation and other operations, so that the construction mode is more flexible.

Example embodiment 1

The present exemplary embodiment provides a differential pressure control type check valve.

Fig. 1 is a schematic view showing an opened state of a differential pressure control type check valve according to an exemplary embodiment of the present utility model; FIG. 2 is a schematic diagram showing a closed state of a differential pressure control type check valve according to an exemplary embodiment of the present utility model; FIG. 3 illustrates a schematic diagram of a second locking mechanism in a differential pressure controlled check valve according to an exemplary embodiment of the present utility model; fig. 4 is a schematic view showing a state in which the differential pressure control type check valve is kept locked open during the tripping process according to an exemplary embodiment of the present utility model.

As shown in fig. 1 to 4, the differential pressure control check valve described in the present example may include a sleeve 1, a piston 2, a first locking mechanism 3, and a flap mechanism 4, wherein both the sleeve 1 and the piston 2 may have a cylindrical structure, the sleeve 1 may be sleeved on the piston 2, and a gap is formed between the sleeve 1 and the piston 2; the outer wall of the piston 2 may be formed with a first flange 21, the first flange 21 may be attached to the inner wall of the sleeve 1, so that a gap formed between the sleeve 1 and the piston 2 may be divided into a first chamber 11 and a second chamber 12, the first chamber 11 is located above the second chamber 12, when the pressure in the second chamber 12 is higher than the pressure in the first chamber 11, a pressure difference may be generated at the upper and lower ends of the first flange 21, so that the piston 2 may be pushed to move upward along the axis of the sleeve 1, and the pressure difference control check valve may be adjusted from an open state to a closed state; when the pressure in the first chamber 11 is higher than the pressure in the second chamber 12, a pressure difference may be generated at both upper and lower ends of the first flange 21, so that the piston 2 may be pushed to move downward along the axis of the sleeve 1, and the pressure difference control type check valve may be adjusted from a closed state to an open state.

In this embodiment, the first locking mechanism 3 is installed in the second chamber 12, and the first locking mechanism 3 can lock the piston 2 at the lowest end of the moving stroke, and limit the piston 2 to move upwards in the axial direction, so that the differential pressure control type one-way valve is kept in an open state.

Alternatively, the first locking mechanism 3 may include a first locking member 31 and an adjusting ring 32, where the first locking member 31 may be sleeved on the piston 2 and fixedly disposed in the second chamber 12, a first pawl 311 is formed at an upper end of the first locking member 31, a second flange 22 is disposed on an outer wall of the piston 2, the second flange 22 is located below the first flange 21, and the first pawl 311 may be engaged with the second flange 22 to implement relative fixation between the first locking member 31 and the piston 2, thereby limiting the piston 2 from moving upwards in an axial direction and maintaining the opening of the differential pressure control type check valve; the adjusting ring 32 can be sleeved on the first locking piece 31, the adjusting ring 32 and the first locking piece 31 can be matched through threads, the adjusting ring 32 can be moved up and down along the first locking piece 31 by rotating the adjusting ring 32, and then the clamping locking force between the first pawl 311 and the second flange 22 can be changed by adjusting the length of the arm of force of the first pawl 311, specifically, when the adjusting ring 32 moves up along the first locking piece 31, the locking force of the first locking piece 31 on the piston 2 is increased, and when the adjusting ring 32 moves down along the first locking piece 31, the locking force of the first locking piece 31 on the piston 2 is reduced; however, the present utility model is not limited thereto, and the first locking mechanism 3 may include components not limited to the first locking member 31 and the adjusting ring 32, but may be other components that can be used to lock the piston; other connection manners than screw-threaded engagement, such as slide rail and slide groove engagement, are also possible between the first locking member 31 and the adjusting ring 32, which is not particularly limited in the present utility model.

In the present embodiment, the valve clack mechanism 4 may be installed in the second chamber 12 below the first locking mechanism 3, the piston 2 is limited at the lowermost end of its travel when the differential pressure control check valve is maintained in the open state, at this time, the valve clack mechanism 4 is limited in the gap between the piston 2 and the sleeve 1 by the piston 2, and the inner cavity of the piston 2 may communicate with the space below the piston 2; when the pressure difference control type one-way valve is required to be adjusted from an open state to a closed state, the piston 2 is pushed to move upwards along the axial direction, the valve clack mechanism 4 is not limited by the piston 2 at the moment, and can be turned upwards and blocked at the lower end of the piston 2 under the action of the self elastic force to separate the inner cavity of the piston 2 from the space below the piston 2, so that the pressure difference control type one-way valve is closed.

Alternatively, the valve clack mechanism 4 may include a valve clack 41 and an elastic member 42, where the valve clack 41 may be fixedly connected with one end of the elastic member 42, and the other end of the elastic member 42 may be fixedly connected with the inner wall of the sleeve 1, when the piston 2 is located at the lowest end of its travel, the piston 2 may resist the elastic force generated by the elastic member 42, so as to limit the valve clack 41 in a gap between the piston 2 and the sleeve 1, when the piston 2 moves upward and leaves the valve clack 41, and after the piston 2 moves away from the valve clack 41, the limiting effect of the piston 2 on the valve clack 41 disappears, the elastic force exerted by the elastic member 42 on the valve clack 41 may drive the valve clack 41 to turn upwards, and seal the lower end of the piston 2, so as to implement the closing of the differential pressure control type one-way valve; however, the present utility model is not limited thereto, and the components that may be included in the valve flap mechanism 4 are not limited to the valve flap 41 and the elastic member 42, but may be other components that may be used to block the piston 2, and the present utility model is not particularly limited thereto.

In this embodiment, the sidewall of the piston 2 may be provided with 2 first side holes 23 that radially penetrate, specifically, the 2 first side holes 23 are all formed above the first flange 21, that is, the 2 first side holes 23 may all connect the inner cavity of the piston 2 with the first chamber 11, and the fluid in the inner cavity of the piston 2 may enter the first chamber 11 along the 2 first side holes 23; the side wall of the sleeve 1 may be provided with 2 radially penetrating second side holes 13, specifically, the 2 second side holes 13 are all formed below the first flange 21, that is, the 2 second side holes 13 may both communicate an external space of the sleeve 1 (when the check valve is located downhole, the external space of the sleeve 1 corresponds to an annular space between the sleeve 1 and a downhole casing, that is, an oil casing annulus) with the second chamber 12, and fluid outside the sleeve 1 may enter the second chamber 12 along the 2 second side holes 13; that is, the pressure in the first chamber 11 can be regulated by varying the fluid pressure in the inner chamber of the piston 2, and the pressure in the second chamber 12 can be regulated by varying the fluid pressure in the oil collar air; however, the present utility model is not limited thereto, and the number of the first side holes 23 and the second side holes 13 may be any number other than 2, and the present utility model is not particularly limited thereto.

Optionally, the differential pressure control check valve may further include a sand control ring 5, where the sand control ring 5 is sleeved on the piston 2 and is located in the first chamber 11, specifically, the sand control ring 5 may be disposed outside the first side hole 23, a plurality of linear cutting seams are formed on the sand control ring 5, when fluid flows into the first chamber 11 along the first side hole 23, the fluid needs to be filtered by the sand control ring 5, a liquid portion in the fluid may enter the first chamber 11 through the linear cutting seams on the sand control ring 5, and solid impurities (such as sand grains) in the fluid cannot enter the first chamber 11 through the linear cutting seams on the sand control ring 5, so that the sand control ring 5 may realize the filtering effect on the fluid passing through the first side hole 23.

Optionally, a water hole screw 131 and a filter screen 132 may be installed in the second side hole 13, the water hole screw 131 may be detachably installed in the second side hole 13, and the water hole screw 131 may seal the second side hole 13 to prevent fluid from flowing inside and outside the sleeve 1; specifically, the filter screen 132 may be made of stainless steel material, the filter screen 132 may filter the fluid flowing through the second side hole 13, and may allow the liquid portion of the fluid to enter the interior of the sleeve 1 through the second side hole 13, and prevent solid impurities (such as sand particles, etc.) in the fluid from entering the interior of the sleeve 1 through the second side hole 13; however, the present utility model is not limited thereto, and the material of the filter screen 132 is not limited to stainless steel, but may be other materials capable of achieving the filtering function, and the present utility model is not limited thereto.

In this embodiment, the differential pressure control type check valve may further include a second locking mechanism 7 and an upper joint 6, the upper joint 6 may be fixedly connected to the upper end of the sleeve 1 through a threaded fit, the second locking mechanism 7 may be thrown into the upper joint 6 when the differential pressure control type check valve is in an open state, and then pumped to the piston 2, so that the second locking mechanism 7 abuts against the upper end of the piston 2 and fixes the second locking mechanism 7 in the upper joint 6, thereby limiting the piston 2 at the lowest end of its movement stroke, preventing the differential pressure control type check valve from closing, and keeping the differential pressure control type check valve in an open state; however, the present utility model is not limited thereto, and the upper joint 6 and the sleeve 1 may be connected by other means than screw engagement, which is not particularly limited thereto.

Alternatively, the second locking mechanism 7 may include a second locking member 71 and a valve core 72, the second locking member 71 having a second pawl 711 formed at an upper end thereof, the second pawl 711 being engageable with a catch groove on an inner wall of the upper joint 6 to fix the second locking member 71 in the upper joint 6, thereby locking the piston 2 at a lowermost end of its travel, restricting the piston 2 from ascending; the valve core 72 may be disposed in the second locking member 71, specifically, the valve core 72 may be a steel ball, and the valve core 72 and the second locking member 71 may form a one-way valve structure, which may allow fluid below the second locking member 71 to flow upward and prevent fluid above the second locking member 71 from flowing downward; however, the present utility model is not limited thereto, and the second locking mechanism 7 may include components not limited to the second locking piece 71 and the valve element 72, but may be other components that can limit the piston 2 and realize a one-way circulation function, and the present utility model is not limited thereto.

In this embodiment, the differential pressure control check valve may further include a lower connector 8, where the lower connector 8 may be mounted at the lower end of the sleeve 1 by a threaded fit, and an inner cavity of the lower connector 8 may be communicated with an inner cavity of the piston 2 and an inner cavity of the sleeve 1; however, the present utility model is not limited thereto, and the lower joint 8 and the sleeve 1 may be connected by other means than screw engagement, which is not particularly limited thereto.

The operation of the differential pressure control check valve described in the present exemplary embodiment is described in detail as follows:

the differential pressure control type one-way valve is connected to a specified position of a pipe column and drilled down according to construction design requirements, and in the fracturing construction process, as shown in fig. 1, the differential pressure control type one-way valve is in an open state, and at the moment, a first pawl of a first locking piece is clamped on a second flange of a piston, so that the piston is locked at the lowest end of a moving stroke of the piston.

As shown in FIG. 2, after the last stage of fracturing construction is finished, before the position of the drill string is regulated under pressure, the pressure at the lower part of the oil pipe needs to be blocked, namely the check valve needs to be closed, at the moment, the pumping of fluid into the oil pipe can be stopped, then the pumping displacement of the annular space is gradually increased and the pumping of fluid is continued for a period of time by pumping the fluid into the annular space of the oil jacket, so that the pressure of the annular space of the oil jacket is higher than the pressure in the oil pipe, a certain pressure difference is formed, as the first cavity is communicated with the inner cavity of the piston, the second cavity is communicated with the annular space of the oil jacket, the pressure in the second cavity is higher than the pressure in the first cavity, when the pressure difference reaches the closing pressure difference of the check valve, the piston overcomes the locking force of the first locking mechanism to go upwards, the limiting effect of the piston on the valve clack mechanism disappears, the valve clack can be blocked at the lower end of the piston under the action of the elastic force, and at the moment, the pressure difference control type check valve is switched into a closed state.

As shown in fig. 1, after the position of the drill string is regulated under pressure, the plugging of the oil pipe needs to be relieved, that is, the check valve needs to be opened, fluid can be pumped into the oil pipe at the moment, the pressure in the oil pipe is higher than the pressure in the oil sleeve annulus to form a certain pressure difference, the first chamber is communicated with the inner cavity of the piston, the second chamber is communicated with the oil sleeve annulus, the pressure in the first chamber is higher than the pressure in the second chamber, when the pressure difference reaches the opening pressure difference of the check valve, the piston descends and is locked again by the first locking mechanism, the valve clack is limited between the sleeve and the piston again, the inner channel of the check valve is smooth at the moment, and the pressure difference control type check valve is switched to an opening state again at the moment.

As shown in fig. 4, before the last stage of fracturing construction is ready to drill, in order to prevent the unidirectional valve from being accidentally closed during the drilling operation from affecting the drilling operation, a second locking mechanism is put into an oil pipe and pumped into an upper joint to be abutted against the upper end of a piston, a second pawl at the upper end of the second locking member can be clamped into a clamping groove on the inner wall of the upper joint, the second locking mechanism is fixed in the upper joint, the piston can be effectively prevented from accidentally ascending, and thus the differential pressure control type unidirectional valve can be always locked in an open state, and at the moment, under the cooperation of the second locking member and a valve core, fluid below the second locking member can be allowed to flow upwards, and fluid above the second locking member can be prevented from flowing downwards.

Example embodiment 2

The present exemplary embodiment provides a tool string.

The tool string according to the present exemplary embodiment may include a differential pressure controlled check valve as described in exemplary embodiment 1, and in addition, the tool string according to the present exemplary embodiment may further include other types of downhole tools connected to the lower end and/or the upper end of the differential pressure controlled check valve, such as a fishing device, an MWD measurement while drilling device, a depth measurement device, a casing cutting and forging device, and the like, and may further be connected to other fracturing tools, and the like, and may be used to perform fracturing operations, which is not particularly limited in this respect, and various types of downhole tools may be combined to form the tool string according to the present exemplary embodiment to perform different types of operations downhole.

In summary, the differential pressure control type one-way valve solves the problem of plugging in the oil pipe in the implementation process of the conventional oil pipe pressurized dragging hydraulic jet fracturing process, can realize free switching of plugging or opening fracturing states through simple operation of manufacturing oil jacket differential pressure, has a simple operation method, ensures safer and more efficient pressurized operation, has the function of realizing reverse circulation and other operations, and can be in an open state through simple operation when the pipe column is required to perform reverse circulation and other operations, so that the construction mode is more flexible.

Although the present utility model has been described above with reference to the exemplary embodiments and the accompanying drawings, it should be apparent to those of ordinary skill in the art that various modifications can be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims (10)

1. A differential pressure control type one-way valve is characterized by comprising a sleeve, a piston, a valve clack mechanism and a first locking mechanism, wherein,

the piston penetrates through the sleeve, a gap is formed between the piston and the sleeve, a first flange is arranged on the outer wall of the piston, the first flange is attached to the inner wall of the sleeve, the gap between the piston and the sleeve is divided into a first cavity positioned above and a second cavity positioned below by the first flange, and the piston can move up and down along the axial direction of the sleeve under the action of the pressure difference of the first cavity and the second cavity so as to control the one-way valve to be opened or closed;

the first locking mechanism is arranged in the second chamber and can lock the piston at the lowest end of the moving stroke so as to keep the one-way valve in an open state;

the valve clack mechanism is arranged below the first locking mechanism, can be limited in a gap between the piston and the sleeve by the piston in the opening state of the one-way valve, and can block the lower end of the piston after the piston moves upwards so as to close the one-way valve.

2. The differential pressure control type one-way valve according to claim 1, wherein a second flange is further provided on an outer wall of the piston, the second flange being located below the first flange; the first locking mechanism comprises a first locking piece and an adjusting ring, the first locking piece is sleeved on the piston, a first pawl is formed at the upper end of the first locking piece and can be clamped with the second flange so as to lock the piston at the lowest end of the moving stroke; the adjusting ring is sleeved on the first locking piece, and the adjusting ring can adjust the locking force of the first locking piece to the piston.

3. The differential pressure control type one-way valve according to claim 1, wherein the valve clack mechanism comprises a valve clack and an elastic member, one end of the elastic member is fixedly connected to the inner wall of the sleeve, the other end of the elastic member is fixedly connected with the valve clack, and the valve clack can be turned over under the action of the elasticity of the elastic member so as to be blocked at the lower end of the piston.

4. The differential pressure control type one-way valve according to claim 1, wherein a plurality of first side holes are formed in the side wall of the piston, and the first side holes can communicate the first chamber with the inner cavity of the piston; a plurality of second side holes are formed in the side wall of the sleeve, and the second side holes can be used for communicating the second chamber with the outer wall of the sleeve; the pressure in the first chamber can be adjusted by changing the pressure of the inner chamber of the piston and the pressure in the second chamber can be adjusted by changing the oil jacket annulus pressure outside the sleeve.

5. The differential pressure control type one-way valve according to claim 4, wherein a port screw capable of blocking the second side hole and a filter screen capable of filtering fluid passing through the second side hole are installed in the second side hole.

6. The differential pressure control type one-way valve of claim 4, further comprising a sand control ring sleeved on the piston and positioned at the first side hole, wherein the sand control ring is provided with a plurality of line cutting slits, and the sand control ring can filter fluid passing through the first side hole.

7. The differential pressure controlled check valve of claim 1 further comprising an upper fitting fixedly connected to the upper end of the sleeve and a second locking mechanism capable of being placed in the upper fitting and abutting the upper end of the piston in an open condition of the check valve, limiting the piston to a lowermost end of a travel to prevent the check valve from closing.

8. The differential pressure control type check valve according to claim 7, wherein the second locking mechanism comprises a second locking member and a valve core, a second pawl is formed at the upper end of the second locking member, and the second pawl can be engaged with a clamping groove on the inner wall of the upper joint to fix the second locking member and limit the piston to move upwards; the valve core is arranged in the second locking piece, and can allow fluid below the second locking piece to flow upwards and prevent fluid above the second locking piece from flowing downwards.

9. The differential pressure controlled check valve of claim 1 further comprising a lower connector mounted to a lower end of the sleeve, an interior cavity of the lower connector communicating with the interior cavity of the piston.

10. A tool string comprising a differential pressure controlled one-way valve according to any one of claims 1 to 9.