Water injection valve for water injection well and oil and gas exploitation system comprising same

Abstract

The invention provides a water injection valve for a water injection well and an oil and gas exploitation system comprising the water injection valve. The water injection valve is characterized in that an elastic element is mounted in a valve element; the gland is arranged to be a hollow cavity with the lower portion open, the valve element is installed in the cavity, and a pressing portion in the gland abuts against the elastic element and is used for pressing the elastic element. The gland is sleeved with the ring sleeve, the base presses the gland from bottom to top and is connected with the inner wall face of the ring sleeve, and the valve element is pushed by fluid to move up and down in the axial direction of the gland. The sealing ring is mounted on the outer wall surface of the upper part of the ring sleeve, a connecting part is arranged on the outer wall surface of the lower part of the ring sleeve, and the stress of the sealing ring and the stress of the connecting part are in different directions. The opening and closing actions of the valve element are smooth, and the counter-force value of the elastic element can be accurately set. Several internal parts are made of high-wear-resistance metal alloy materials and can be used for a long time without wear. The outer-layer sleeve is further prevented from being impacted by high-speed water flow due to the outlet flow guide design, and the safety during long-term use is ensured.

Description

Technical Field

[0001] This invention relates to the field of oilfield development, and particularly to a water injection valve for a water injection well and an oil and gas extraction system including the same. Background Technology

[0002] In existing technologies, before oilfield development, the oil, natural gas, and formation water in the reservoir are in a state of high temperature, high pressure, and relative stasis. However, after oilfield development begins, as oil and natural gas are continuously extracted, the bottom hole pressure inevitably decreases, and the reservoir pressure will inevitably decrease with increasing development time. To improve crude oil recovery, water injection is typically used to replenish the reservoir's energy; this is a relatively mature method for maintaining pressure during production. Therefore, water injection in oilfields has become one of the most important tasks in current oil production.

[0003] As oilfields develop, water content increases, and production rises daily. The role of water injection systems in increasing and stabilizing oil production becomes increasingly prominent. Conventional water injection involves drilling several injection wells around the oil well, and after surveying and calculations, injecting an appropriate amount of water into the formation. Due to differences in rock strata properties, sandstone, being a homogeneous and highly permeable formation, easily ensures uniform water injection. However, carbonate rocks are low-permeability and prone to fractures (oil and gas production also relies on fracture extraction). Therefore, in conventional water injection operations, it is difficult to ensure uniform water injection in carbonate rock formations, failing to replenish the pressure in the oil reservoir, leading to injection failure or inefficiency.

[0004] Figure 1 This is a schematic diagram of the structure of a water injection valve in the prior art. (Example:) Figure 1 As shown, in the current structure of the water injection valve, the O-ring 10 is designed to be under pressure on a flat surface. After the bottom thread of the water injection valve is screwed in, pressure is generated, placing high demands on the flatness of the sealing surface and the anti-loosening requirements of the threads. This easily leads to O-ring 10 seal failure. Under pressure, the O-ring 10 is in a compressed state, exerting a reverse force on the valve. Simultaneously, the fluid itself also exerts pressure on the valve, which can cause problems with the O-ring 10 over time. Once the O-ring 10 seal fails, it's equivalent to adding a normally open water injection channel, weakening the water injection valve's efficiency. In severe cases, it can lead to valve failure. Furthermore, the outlet water flow directly impacts the outer casing, posing a risk of wear and damage under long-term production conditions, which could ultimately lead to water injection well failure.

[0005] In view of this, the inventors of this application have designed a water injection valve for water injection wells and an oil and gas extraction system including the valve, in order to overcome the above-mentioned technical problems. Summary of the Invention

[0006] The technical problem solved by the present application is to overcome the low efficiency of the traditional water injection method in the prior art, and to provide a water injection valve for a water injection well and an oil and gas exploitation system comprising the same.

[0007] The present application solves the above technical problem by the following technical scheme: A water injection valve for a water injection well, characterized in that the water injection valve comprises: a valve core, wherein an elastic element is installed in the valve core; a gland, which is provided as a hollow cavity with an open lower part, the valve core is installed in the cavity, and a pressing part in the gland abuts against the elastic element to press the elastic element; a ring sleeve and a base, the ring sleeve is sleeved on the outside of the gland, the base is tightly pressed from bottom to top on the gland, and the inner wall surface of the ring sleeve is connected with the base, and the valve core moves up and down along the axial direction of the gland under the push of fluid; a sealing ring, which is installed on the upper outer wall surface of the ring sleeve, and a connecting part is arranged on the lower outer wall surface of the ring sleeve, and the stress of the sealing ring and the stress of the connecting part are in different directions.

[0008] According to an embodiment of the present application, an installation groove is formed on the valve core, and the elastic element is installed in the installation groove.

[0009] According to an embodiment of the present application, a pressing part is arranged at the upper end of the gland, and the pressing part is aligned with the elastic element up and down.

[0010] According to an embodiment of the present application, a flow channel is formed at the upper end of the gland, an outlet is formed at the top of the gland, the flow channel and the outlet are connected with each other, the gap between the valve core and the base and the gland forms an inlet flow channel, and fluid sequentially passes through the inlet flow channel, the flow channel and the outlet to push the valve core to move close to or away from the upper end of the gland.

[0011] According to an embodiment of the present application, the flow channel comprises a first flow channel and a second flow channel arranged in the vertical direction of the upper end of the gland, and a third flow channel arranged in the horizontal direction of the upper end of the gland, and the third flow channel penetrates the first flow channel, the second flow channel and the outlet in the horizontal direction; the inlet flow channel, the second flow channel to the outlet are sequentially connected to form a main flow channel, and the inlet flow channel, the first flow channel, the third flow channel, the second flow channel to the outlet are connected to form an auxiliary flow channel; When the valve core is in the open state, the main flow channel and the auxiliary flow channel are both in flow; when the valve core is in the closed state, the main flow channel is closed and the auxiliary flow channel is in flow.

[0012] According to one embodiment of the present application, the water injection valve satisfies the following relationship: P1>P2>P3; wherein P1 represents the pressure at the inlet of the inlet flow channel; P2 represents the surface pressure of the valve core; and P3 represents the pressure of the outlet.

[0013] According to one embodiment of the present application, the fluid pressure on the valve core satisfies the following relationship: F1=(P1-P2)×S1; wherein F1 represents the fluid pressure on the valve core; P1 represents the pressure at the inlet of the inlet flow channel; P2 represents the surface pressure of the valve core; and S1 represents the area of the valve core. The pressure of the elastic element on the valve core is F2, when F1<F2, the water injection valve is in the initial open state; when F1>F2, the water injection valve starts to close until the main flow channel is closed.

[0014] According to one embodiment of the present application, the connection between the gland and the ring sleeve and the base is respectively sealed by a sealing structure or a rubber sealing element.

[0015] According to one embodiment of the present application, the water injection valve further comprises a flow guide cover installed between the gland and the ring sleeve for guiding the fluid flowing out of the outlet of the gland to flow along the pipeline axis direction of the water injection well.

[0016] According to one embodiment of the present application, the elastic element comprises an inner ring spring, a spring seat and an outer ring spring, an installation cavity is formed on the valve core, the spring seat is installed in the installation cavity, the inner ring spring is installed in the spring seat and abuts against the gland, and the outer ring spring is installed between the spring seat and the installation cavity.

[0017] The present application further provides an oil and gas exploitation system, characterized in that the oil and gas exploitation system comprises at least one water injection well, and at least one water injection valve for water injection well as described above is installed on the pipeline of each water injection well.

[0018] The positive progress effect of the present application is that: The water injection valve for water injection well and the oil and gas exploitation system comprising the same have the following advantages: I. Small size: under the premise of meeting the production flow and starting pressure, the product can be made very small in size, can be installed in different pipe diameters, and is suitable for oil (gas) wells of various production capacities.

[0019] II. Functionally reliable: the valve core opening and closing action is smooth, the elastic element counterforce value can be accurately set. Internal several parts use high wear-resistant metal alloy materials, which can be used for a long time without wear.

[0020] III. The outlet guide design further avoids the impact of the outer sleeve on the high-speed water flow, ensuring the safety during long-term use.

[0021] IV. The double spring design can greatly reduce the shear stress of the spring, improving the reliability and life of the spring. When the customer has a demand, the closing pressure of the valve can be greatly improved, and the life of the spring is not affected. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other features, properties and advantages of the present application will become more apparent from the following description, taken in conjunction with the accompanying drawings, in which like reference numerals refer to like features throughout the drawings, and wherein: Figure 1 It is a structural schematic diagram of the water injection valve in the prior art.

[0023] Figure 2 It is a structural exploded view of the first embodiment of the water injection valve for the water injection well of the present application.

[0024] Figure 3 It is a cross-sectional view of the first embodiment of the water injection valve for the water injection well of the present application in the valve open state.

[0025] Figure 4 It is a state diagram of the first embodiment of the water injection valve for the water injection well of the present application in the valve open state, opening the water injection.

[0026] Figure 5 It is a cross-sectional view of the first embodiment of the water injection valve for the water injection well of the present application in the valve closed state.

[0027] Figure 6 It is a state diagram of the first embodiment of the water injection valve for the water injection well of the present application in the valve closed state, the main flow passage is closed and the auxiliary flow passage is open.

[0028] Figure 7 It is a schematic diagram of the installation structure of the water injection valve for the water injection well of the present application Figure 1 .

[0029] Figure 8 It is a schematic diagram of the installation structure of the water injection valve for the water injection well of the present application Figure 2 .

[0030] Figure 9 It is a structural exploded view of the second embodiment of the water injection valve for the water injection well of the present application.

[0031] Figure 10Axial sectional view of the second embodiment of the water injection valve for a water injection well according to the present invention.

[0032] Figure 11 Installation schematic view of the second embodiment of the water injection valve for a water injection well according to the present invention.

[0033] Figure 12 Exploded schematic view of the third embodiment of the water injection valve for a water injection well according to the present invention.

[0034] Figure 13 Axial sectional view of the third embodiment of the water injection valve for a water injection well according to the present invention.

[0035] Figure 14 Schematic view of the state in the case of high permeability of the rock formation of a water injection well in the prior art.

[0036] Figure 15 Schematic view of the state in the case of low permeability of the rock formation of a water injection well in the prior art.

[0037] Figure 16 Schematic view of the structure in which the water injection valve is installed on a water injection well in an oil and gas production system according to the present invention.

[0038] REFERENCE NUMERALS

[0039] O-ring 10

[0040] Valve core 100

[0041] Gland 200

[0042] Ring sleeve 300

[0043] Base 400

[0044] Sealing ring 500

[0045] Elastic element 110

[0046] Mounting groove 120

[0047] Groove 310

[0048] Connection portion 320

[0049] Outlet 210

[0050] First flow passage 220

[0051] Second flow passage 230

[0052] Third flow passage 240

[0053] Plugging pin 231

[0054] Inlet flow passage A

[0055] Pressing portion 250

[0056] Spring reaction force F2

[0057] Mounting hole 600

[0058] Mounting socket 700

[0059] Flow guide cover 800

[0060] Connection base 810

[0061] End cap 820

[0062] Flow guide groove 830

[0063] Pipe 20

[0064] Sleeve 21

[0065] Pressing ring 840

[0066] Mounting cavity 130

[0067] Inner ring spring 111

[0068] Spring seat 112

[0069] Outer ring spring 113

[0070] Water injection valve 30 DETAILED DESCRIPTION

[0071] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below in combination with the drawings.

[0072] Reference will now be made in detail to the embodiments of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0073] Further, although the terms used in the present application are selected from publicly-known and used terms, some of the terms mentioned in the specification of the present application can be selected by the applicant at his or her discretion, with their detailed meanings being described in relevant parts of the description herein.

[0074] Further, the present application is to be understood not only in the sense of the actual claimed novel technical solutions per se, but also in the sense associated with the meaning that each term implies.

[0075] As Figures 2 to 6The water injection valve for a water injection well comprises a valve core 100, a gland 200, a ring sleeve 300, a base 400 and a sealing ring 500. The valve core 100 is internally provided with an elastic element 110. For example, a mounting groove 120 is formed on the valve core 100, and the elastic element 110 is mounted in the mounting groove 120. The valve core 100 can be preferably in a columnar block structure, and the elastic element 110 can be preferably a spring.

[0076] In the embodiment, the valve core 100 is completely built-in, and forms a hole and a shaft cooperation relationship with the cooperating gland, the opening and closing movement is smooth, and the opening and closing stroke parameters are accurately limited. The elastic element 110 is built-in the valve core 100, which can avoid the scouring of the produced liquid and protect it from being worn. The pressure corresponding to the initial opening of the valve core and the flow are pre-set, and the starting pressure can be pre-set according to the specific downhole parameters of the water injection well.

[0077] The ring sleeve 300 is sleeved on the outside of the gland 200, the base 400 is tightly pressed from bottom to top on the gland 200, and is connected with the inner wall surface of the ring sleeve 300, the valve core 100 moves up and down along the axial direction of the gland 200 under the pushing of the fluid. The sealing ring 500 is mounted on the upper outer wall surface of the ring sleeve 300, for example, a groove 310 is formed on the upper outer wall surface of the ring sleeve 300, and the sealing ring 500 is mounted in the groove 310. The lower outer wall surface of the ring sleeve 300 is provided with a connecting portion 320, for example, the connecting portion 320 can be provided in a threaded structure.

[0078] When the water injection valve is installed, the ring sleeve 300 is connected with the pipeline of the water injection well through the connecting portion 320, the connecting portion 320 is subjected to a force in the up-down direction, the sealing ring 500 and the wall surface of the pipeline are extruded, and are subjected to a force in the horizontal direction. In this way, the stress direction of the sealing ring 500 and the stress direction of the connecting portion 320 are in different directions, for example, the stress direction of the sealing ring 500 and the stress direction of the connecting portion 320 form a perpendicular relationship in the embodiment, so that the sealing failure of the sealing ring 500 is avoided, and the service life of the sealing ring 500 and the connecting portion 320 is effectively prolonged.

[0079] The gland 200 is provided as a lower open type hollow cavity, the valve core 100 is mounted in the cavity, and there is a gap between the valve core 100 and the inner wall surface of the cavity. A flow channel is formed on the upper end of the gland 200, and an outlet 210 is formed on the top of the gland 200, and the flow channel and the outlet 210 are in communication with each other.

[0080] Preferably, the flow channel comprises a first flow channel 220 arranged in the vertical direction of the upper end of the gland 200, a second flow channel 230, and a third flow channel 240 arranged in the horizontal direction of the upper end of the gland 200, and the first flow channel 220, the second flow channel 230 and the third flow channel 240 are in communication with each other. For example, Figure 4As shown, the first flow channel 220 and the second flow channel 230 are arranged alternately, and the third flow channel 240 extends horizontally through the first flow channel 220, the second flow channel 230, and the outlet 210. Here, the third flow channel 240 can be configured as a through hole that extends through the inside and outside of the pressure cap 200, which facilitates the machining of the parts. Then, the outer ends on both sides of the third flow channel 240 are sealed by sealing pins 231 to form an internal flow channel. The gap between the valve core 100, the base 300, and the pressure cap 200 forms the inlet flow channel A. Fluid flows sequentially through the inlet flow channel A, the flow channels (first flow channel 220, second flow channel 230, and third flow channel 240), and the outlet 210, pushing the valve core 100 closer to or away from the upper end of the pressure cap 200.

[0081] Here, the inlet channel A, the second channel 230, and the outlet 210 are connected in sequence to form the main channel. The inlet channel A, the first channel 220, the third channel 240, the second channel 230, and the outlet 210 are connected to form the auxiliary channel.

[0082] The upper end of the pressure cap 200 is also provided with a pressing part 250, which is aligned vertically with the elastic element 110 and abuts against the elastic element 110 to press the elastic element 110. During the pressing process, the elastic element 110 generates a spring reaction force F2 that moves downward along the valve core 100.

[0083] like Figure 4 As shown, the initial state of the water injection valve is set to the open water injection state. When the valve core 100 is in the open state, the main flow channel (inlet flow channel A, second flow channel 230 to outlet 210) and the auxiliary flow channel (inlet flow channel A, first flow channel 220, third flow channel 240, second flow channel 230 to outlet 210) are both open.

[0084] In this state, the water injection valve satisfies the following relationship: P1>P2>P3; where P1 represents the inlet pressure of the inlet channel; P2 represents the surface pressure of the valve core; and P3 represents the outlet pressure. When the water injection valve is in the open state, the internal elastic element 110 provides a spring reaction force F2, forcing the valve core to be in the open state (e.g., Figure 4 (As shown).

[0085] The fluid pressure on the valve core satisfies the following relationship: F1=(P1-P2)×S1; where F1 represents the fluid pressure on the valve core; P1 represents the pressure at the inlet of the inlet channel; P2 represents the surface pressure of the valve core; and S1 represents the area of ​​the valve core.

[0086] The pressure of the elastic element 110 (such as a spring) on the valve core 100 is F2. When F1 < F2, the water injection valve is in the initial open state. When the water injection valve is in the open state, the flow rate through the valve is normal, and the valve can achieve normal water injection operation.

[0087] When there are cracks in the formation at a certain water injection valve, resulting in a significant increase in the water injection flow rate, the large flow rate will cause an increase in the pressure difference between P1 - P2, thereby causing (P1 - P2) × S1 > F2, that is, F1 > F2. The valve starts to close until the main flow channel is finally closed, and only the normally open flow channel maintains a small flow rate of water injection, that is, only the auxiliary flow channel is opened.

[0088] As Figure 5 shown, the water injection valve changes to the closed state. When the valve core 100 is in the closed state, the main flow channel (inlet flow channel A, second flow channel 230 to outlet 210) is closed, and the normally open flow channel injects water with a small flow rate, that is, the auxiliary flow channel (inlet flow channel A, first flow channel 220, third flow channel 240, second flow channel 230 to outlet 210) is in circulation.

[0089] After the water injection valve is closed due to a large flow rate, the force on the valve core 100 changes as follows: P1 × S1 - P2’ × S1’ > F2’, and the water injection valve remains in the closed state; P1 × S1 - P2’ × S1’ < F2’, and the water injection valve starts to open; Among them, P1 represents the pressure at the inlet of the inlet flow channel; P2’ represents the surface pressure of the valve core; S1 represents the area of the valve core; S1’ represents the sealing area of the valve core; F2’ represents the spring reaction force.

[0090] That is to say, if you want to reopen the closed water injection valve, you need to reduce the water injection pressure to a certain value, and the valve can reopen.

[0091] Regarding the flow rate adjustment of the closed water injection valve: For different water injection (gas) wells, due to production considerations, producers have different requirements for the closed flow rate of the valve. Customers can adjust the flow - through area of the main flow channel to obtain different closed flow rates. The flow rate adjustment of the water injection valve depends on the structural parameters of the components related to the main flow channel. When the cross - sectional area of the main flow channel increases, the corresponding water injection flow rate under the same production pressure difference will increase, and vice versa.

[0092] Regarding the pressure adjustment of the closed water injection valve: If the producer has requirements for the closing pressure of the valve, the corresponding elastic element value can be adjusted in advance to match different closing pressures.

[0093] In addition, since the water injection valve is composed of several parts, the reliability of its work depends on the accurate pressure value, and slight sealing failure can cause pressure loss, thereby affecting the performance parameters of the water injection valve. Long-term leakage can also cause wear of the parts, leading to failure of the pressure valve and affecting the production of the entire well. Therefore, in the present embodiment, the water injection valve increases the design of the sealing structure, such as increasing the internal sealing structure and the external sealing structure.

[0094] The sealing design inside the water injection valve can adopt face sealing design, for example, the connection between the gland 200 and the ring sleeve 300, and the base 400 is respectively formed by a sealing structure to form face sealing (such as metal face sealing). This sealing structure is simple in processing technology and reliable in sealing effect. Of course, the water injection valve can also be sealed by a rubber sealing element, such as an O-shaped sealing ring.

[0095] Since the water injection valve needs to be installed on the pipeline, the external part of the water injection valve also needs to be sealed. For example, the water injection valve is installed by thread connection, and the connection with the pipeline also needs to be sealed. In the present embodiment, the sealing structure outside the water injection valve adopts two seals, namely the first external sealing position B and the second external sealing position C. The second external sealing position C adopts an O-shaped sealing ring as the main sealing, which can achieve complete sealing, and the first external sealing position B adopts metal face sealing as an auxiliary sealing method.

[0096] As shown in Figure 7 and Figure 8 In the present embodiment, the connection between the parts of the water injection valve adopts hole, shaft cooperation connection, and thread connection. The assembly of the water injection valve needs to use special tools, and the internal thread connection is coated with thread glue to prevent loosening and rotation. When the water injection valve is assembled, if it needs to be disassembled, special tools also need to be used, otherwise it cannot be disassembled. The finished assembly of the water injection valve adopts anti-disassembly design and needs to be installed and disassembled by special tools. The internal part of the water injection valve adopts thread connection, and the product is not assembled by screws.

[0097] The water injection valve is installed on the production pipeline by thread connection. The screwing of the thread needs to provide a suitable connection method. Figure 7 and Figure 8 The installation hole 600 design and the installation bayonet 700 design can provide effective installation torque to ensure that the water injection valve can be installed in place. Of course, the shape and number of the installation hole 600 and the installation bayonet 700 here are only schematic, and can be adjusted according to the actual situation, which is not limited here.

[0098] Embodiment two: As shown in Figures 9 to 11As shown, the structure of the present embodiment is basically the same as that of Embodiment One, except that the water injection valve further comprises a flow guide cover 800, which is installed between the gland 200 and the ring 300, for guiding the fluid flowing out of the outlet of the gland 200 to flow along the axis of the pipe 20 of the injection well.

[0099] Preferably, the flow guide cover 800 comprises a connecting base 810 and an end cover 820, which is installed at the upper end of the connecting base 810. The end cover 820 and the upper end of the connecting base 810 are different by a flow guide groove 830. The fluid flowing out of the outlet 210 of the water injection valve flows along the flow guide groove 830, thereby avoiding the fluid from washing the outer sleeve 21 of the pipe 20. The lower end of the connecting base 810 is connected and fixed with the ring 300.

[0100] As shown in Figure 11 , the water flow out of the outlet of the water injection valve (e.g. the structure of Embodiment One) directly washes the sleeve 21 outside the pipe 20, as shown by the arrow in Figure 11 . Such installation structure is prone to cause the sleeve to be eroded and damaged, affecting the normal operation of the water injection valve. Therefore, the structure of the present embodiment adds the flow guide cover 800, which can be adjusted in rotation to adjust the angle of the outlet, so that the fluid outlet is along the axis of the pipe 20, avoiding washing the sleeve 21 outside the pipe 20. The flow guide cover 800 can accurately adjust the direction of the jet flow of the outlet, to the greatest extent protecting the erosion and wear of the outer sleeve, and improving the reliability and effectiveness of the injection well.

[0101] Further preferably, the flow guide cover 800 and the ring 300 are connected through a compression ring 840. One side wall surface of the compression ring is connected with the ring 300, e.g. through threaded connection. The other side wall surface of the compression ring 840 is locked and fixed with the lower end of the flow guide cover 800.

[0102] Embodiment Three As shown in Figure 12 and Figure 13 , the structure of the present embodiment is basically the same as that of Embodiment Two, except that the elastic element 110 of the present embodiment comprises an inner coil spring 111, a spring seat 112 and an outer coil spring 113. An installation cavity 130 is formed in the valve core 100, the spring seat 112 is installed in the installation cavity 130, the inner coil spring 111 is installed in the spring seat 112 and abuts against the gland 200, and the outer coil spring 113 is installed between the spring seat 112 and the installation cavity 130.

[0103] When the customer needs to greatly increase the closing pressure of the water injection valve, merely increasing the mechanical parameters (such as hardness, wire diameter, etc.) of the elastic element 110 cannot meet the design requirements, or will increase the potential failure risk of the elastic element 110. Therefore, in the embodiment, the elastic element 110 is provided as a built-in mechanism of double springs, which, through the series combination of the two springs, not only does not increase the failure risk of the spring itself, but also comprehensively increases the equivalent spring pressure, and finally increases the closing pressure of the water injection valve.

[0104] Alternatively, the double-spring design greatly reduces the shear stress inside the spring without the need to increase the closing pressure of the water injection valve, thereby greatly reducing the failure risk of the spring itself and further improving the performance stability of the water injection valve.

[0105] The series double-spring design inside the water injection valve first effectively reduces the shear stress inside the spring without changing the valve closing pressure, greatly improving the reliability and service life of the spring. Secondly, when the customer needs to increase the valve closing pressure, the double-spring structure design greatly increases the comprehensive pressure without affecting the reliability of the spring, thereby greatly increasing the closing pressure of the valve.

[0106] Of course, the double-spring structure of the elastic element in the embodiment can also be applied to the water injection valve structure of embodiment one or other water injection valve structures, and can also achieve the effect of improving the performance stability of the water injection valve. Herein, only examples are given, and the application is not limited thereto.

[0107] As shown in Figure 16 , the application also provides an oil and gas exploitation system, which comprises at least one water injection well, and at least one water injection valve 30 for the water injection well as described above is installed on the pipeline 20 of the water injection well.

[0108] If the permeability of the rock stratum of the water injection well is high and uniform water injection can be ensured, the pressure of the entire stratum can be uniformly restored (as shown in Figure 14 ). If the permeability of the rock stratum of the water injection well is low and there are cracks, most of the water injection will enter the rock stratum along the cracks without the water injection valve, the stratum pressure recovery is extremely uneven, and the parameter requirements of the water injection well cannot be met (as shown in Figure 15 ).

[0109] As shown in Figure 16As shown, in the case of low permeability of the water injection well rock formation, if the water injection valve is installed, when the flow of the fracture section is too large, the corresponding pressure difference of the water injection valve will increase accordingly, until the set closing pressure is reached, the main flow passage of the water injection valve will be closed, only the small flow auxiliary flow passage is reserved, and other no-leakage sections will not be closed due to the pressure of the water injection valve. Thus, water injection into the rock formation can continue, and the pressure in the formation is effectively supplemented.

[0110] According to the above structural description, the water injection valve for the water injection well can automatically adjust the water injection amount according to the permeability and pressure of different sections of the formation. When the permeability of the region is high, the valve flow is normal, and the water injection operation is normally carried out. When the permeability of a certain region is low and there is a pressure fracture, the flow of the valve will increase significantly. When the flow exceeds the set threshold, the valve will be closed, only a small flow of the "normally open" is reserved, and water injection into the formation continues. In actual water injection operation, a water injection well will pass through different formations, some regions have high permeability and no formation fracture. Some regions have low permeability and formation fractures. The application of the water injection valve can effectively solve the difficulty of traditional water injection operation, that is, a large amount of water is injected into the formation, but the formation pressure required for oil and gas production is not effectively improved.

[0111] In summary, the water injection valve for the water injection well and the oil and gas production system comprising the same have the following advantages: I. Simple structure: the product has few parts, is easy to install, and has reliable function.

[0112] II. Small size: the product can be very small in size under the premise of meeting the production flow and starting pressure, can be installed in different pipe diameters, and is suitable for various yield oil (gas) wells.

[0113] III. Low cost: the material cost of the water injection valve is low.

[0114] IV. Reliable function: the opening and closing actions of the valve core are smooth, the counterforce value of the elastic element can be accurately set, and the internal several parts are made of high wear-resistant metal alloy material, which can be used for a long time without wear.

[0115] V. Simple part processing and assembly process, further reducing the total cost of the product; VI. The outlet flow guide design further avoids the impact of the high-speed water flow on the outer sleeve, ensuring the safety during long-term use.

[0116] VII. The double-spring design can greatly reduce the shear stress of the spring, improve the reliability and service life of the spring, and greatly increase the closing pressure of the valve when the customer needs, without affecting the service life of the spring.

[0117] The foregoing disclosure of the application merely represents examples of the application and is not limiting of the application. Various modifications, improvements, and alterations of the application can become apparent to those skilled in the art from the foregoing disclosure without departing from the spirit and scope of the application. Such modifications, improvements, and alterations are intended to be within the scope of the application.

[0118] Also, the use of "an" or "one" to describe the application, or any feature or component of the application, is not to be construed to exclude the presence of more than one of such feature or component. In other words, the singular includes the plural unless indicated otherwise. Similarly, "another" is defined as a second or additional instance, rather than the only instance. The terms "comprise," "comprising," "include," "including," and "has" or "have" are used in the inclusive, open sense and are not meant to exclude other components or features. The terms "a" and "an" are used in the sense of "one or more" unless otherwise specified.

[0119] Similarly, it is to be noticed that the term "comprising", used in the description, is not used in the sense of "consisting only of" to limit the present application. Limiting the scope of the application to the exact number of constituents recited in each claim is not intended. It is to be noted that, as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component" includes a plurality of such components. In this specification and in the claims that follow, reference can be made to a plurality of devices or structures by using the term "at least one," and this does not imply that the specification and claims are intended to convey to the patent officer the intent that any one of these prepositions can be interpreted to exclude the presence of the other prepositions. Also, the use of the term "about" is intended to cover variations known in the art to fall within the scope of the value stated. For example, "about 10%" covers 9% and 11%.

[0120] Accordingly, in some embodiments, the numerical parameters in the specification and claims are approximations that can vary depending upon the requirements of the particular application. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broadest scope of the application are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, can contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0121] While the application has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the application pertains.

Claims

1. A water injection valve for a water injection well, characterized in that, The water injection valve includes: a valve core, in which an elastic element is installed; a gland, which is arranged as an open-bottomed hollow cavity, the valve core is installed in the cavity, and the pressing part in the gland abuts against the elastic element for pressing the elastic element; a collar and a base, the collar is sleeved outside the gland, the base presses the gland from bottom to top and is connected to the inner wall surface of the collar, and the valve core moves up and down along the axis of the gland under the push of the fluid; a sealing ring, the sealing ring is installed on the upper outer wall surface of the collar, a connecting part is arranged on the lower outer wall surface of the collar, and the forces on the sealing ring and the connecting part are in different directions.

2. The water injection valve for a water injection well as described in claim 1, characterized in that, An installation groove is formed on the valve core, and the elastic element is installed in the installation groove.

3. The water injection valve for a water injection well as described in claim 1, characterized in that, The upper end of the gland is provided with a pressing part, and the pressing part is vertically aligned with the elastic element.

4. The water injection valve for a water injection well as described in claim 1, characterized in that, A flow channel is formed at the upper end of the gland, and an outlet is formed at the top of the gland, and the flow channel and the outlet are interconnected; the gaps between the valve core, the base and the gland form an inlet flow channel, and the fluid sequentially passes through the inlet flow channel, the flow channel and the outlet to push the valve core to approach or move away from the upper end of the gland.

5. The water injection valve for a water injection well as described in claim 4, characterized in that, The flow channel includes a first flow channel and a second flow channel arranged along the vertical direction of the upper end of the gland, and a third flow channel arranged along the horizontal direction of the upper end of the gland, and the third flow channel penetrates through the first flow channel, the second flow channel and the outlet in the horizontal direction; The inlet flow channel, the second flow channel to the outlet are sequentially interconnected to form a main flow channel, and the inlet flow channel, the first flow channel, the third flow channel, the second flow channel to the outlet are interconnected to form an auxiliary flow channel; When the valve core is in the open state, both the main flow channel and the auxiliary flow channel are in circulation; when the valve core is in the closed state, the main flow channel is closed and the auxiliary flow channel is in circulation.

6. The water injection valve for a water injection well as described in claim 4, characterized in that, The water injection valve satisfies the following relationship: P1 > P2 > P3; where, P1 represents the pressure at the inlet of the inlet flow channel; P2 represents the surface pressure of the valve core; P3 represents the pressure at the outlet.

7. The water injection valve for a water injection well as described in claim 5, characterized in that, The fluid pressure received by the valve core satisfies the following relationship: F1 = (P1 - P2) × S1; where, F1 represents the fluid pressure received by the valve core; P1 represents the pressure at the inlet of the inlet flow channel; P2 represents the surface pressure of the valve core; S1 represents the area of the valve core; The pressure of the elastic element on the valve core is F2. When F1 < F2, the water injection valve is in the initial open state; when F1 > F2, the water injection valve starts to close until the main flow channel is closed.

8. The water injection valve for a water injection well as described in claim 1, characterized in that, The connections between the gland and the collar and the base respectively form surface seals through sealing structures or are sealed with rubber seals.

9. The water injection valve for a water injection well as described in claim 1, characterized in that, The water injection valve further includes a diversion cover, which is installed between the gland and the collar and is used to guide the fluid flowing out of the outlet of the gland to flow along the axis direction of the injection well pipe.

10. The water injection valve for a water injection well as described in claim 1, characterized in that, The elastic element includes an inner spring, a spring seat, and an outer spring. A mounting cavity is formed on the valve core. The spring seat is installed in the mounting cavity. The inner spring is installed in the spring seat and abuts against the pressure cap. The outer spring is installed between the spring seat and the mounting cavity.

11. An oil and gas extraction system, characterized in that, The oil and gas extraction system includes at least one water injection well, and each water injection well has at least one water injection valve for the water injection well as described in any one of claims 1-10 installed on its pipeline.

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