Water control screen pipe with backflow prevention function

Abstract

A water control screen pipe with a backflow prevention function comprises a base pipe and a shell, an ICD valve is arranged on the side wall, covered by the shell, of the base pipe and comprises a flow guide channel, a flow control unit is arranged in the flow guide channel, when the well bottom pressure difference is in the forward direction, the flow control unit is located at the first position, and when the well bottom pressure difference is in the reverse direction, the flow control unit is located at the second position. Fluid in the wellbore annulus is not prevented from flowing into the base pipe from the outside of the base pipe through the flow guide channel; and when the well bottom pressure difference is reverse, the flow control unit is located at the second position, the flow guide channel is closed, and the fluid in the base pipe is prevented from flowing into the exterior of the base pipe from the interior of the base pipe through the flow guide channel. When the flow guide channel, provided with the sealing device, on the water control screen pipe needs to be opened, the flow guide channel of the ICD valve can be closed only by filling high-pressure fluid into the base pipe to form reverse shaft bottom pressure difference, the filled fluid can be prevented from leaking into a shaft annulus, high pressure in a central pipe column can be easily established, and the opening pressure of the sealing device can be easily achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil extraction, and relates to a water control screen pipe device, and in particular to a water control screen pipe with a backflow prevention function. Background Art

[0002] During the oil production process, due to the different geological structures and reserves of different strata in the reservoir, it is necessary to artificially control the oil and gas production sequence and production flow of different strata. A water control screen with a pressure-controlled opening function came into being. The principle is that part or all of the diversion channels of the water control screen are closed by a sealing device (such as a bursting diaphragm). Under the condition of a positive bottom hole pressure difference (that is, the pressure in the wellbore annulus is greater than the pressure in the center pipe column), the closed diversion channel does not participate in production; when the diversion channel is needed to participate in production, it is only necessary to inject high-pressure fluid into the center pipe column to form a reverse bottom hole pressure difference. The reverse bottom hole pressure difference makes the sealing device invalid (for example, the bursting diaphragm is broken), and the diversion channel can be opened to participate in the later production. Furthermore, the sealing device can also be set with different opening pressure levels (such as bursting diaphragms of different thicknesses), so that it can be selectively opened by pressures of different levels. In addition, there is also a water control screen with a pressure-controlled closing function, which will not be repeated here.

[0003] In order to ensure reliable opening or closing of the diversion channel and avoid malfunction, the opening pressure needs to be set slightly higher than the production pressure. However, when high-pressure fluid is injected into the center string to generate the opening or closing pressure, the injected fluid will leak from the center string to the wellbore annulus due to the reverse bottomhole pressure difference in the bidirectional common diversion channel or the opened controllable diversion channel. Therefore, it is difficult to achieve precise control of the reverse bottomhole pressure difference at various locations in the center string, especially in the deeper positions in the wellbore, where it is difficult to generate a high reverse bottomhole pressure difference. Summary of the invention

[0004] The purpose of this patent is to overcome the defects of the prior art and provide a water control screen with anti-backflow function, which is conducive to achieving precise control of the reverse pressure difference at various locations in the central pipe column and generating a higher reverse bottom hole pressure difference at a deeper position in the wellbore.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A water control screen pipe with a backflow prevention function comprises a base pipe and an outer shell; wherein the outer shell is a cylindrical structure, coaxially arranged on the circumferential outer side of the base pipe, the two ends of the outer shell are sealed and connected to the circumferential outer side of the base pipe, and a screen is arranged in the middle; an ICD valve is arranged at the side wall position of the base pipe covered by the outer shell, and the ICD valve comprises a diversion channel, and the diversion channel runs through the outside and the inside of the side wall of the base pipe; a flow control unit is arranged in the diversion channel of the ICD valve, wherein when the bottom hole pressure difference is positive, the flow control unit is located at a first position, and does not prevent the fluid in the wellbore annulus from flowing from the outside of the base pipe into the inside of the base pipe through the diversion channel; when the bottom hole pressure difference is reverse, the flow control unit is located at a second position, closing the diversion channel, thereby preventing the fluid in the base pipe from flowing from the inside of the base pipe into the outside of the base pipe through the diversion channel.

[0007] Furthermore, the ICD valve includes a guide seat, a valve seat and a valve ring, wherein the valve seat is a circular ring structure, arranged in the first through hole of the side wall of the base pipe; the guide seat is a circular ring structure, the outer diameter of the guide seat is consistent with the inner diameter of the valve seat, and is fixedly arranged inside the valve seat at one end close to the axis of the base pipe; the valve ring is a circular ring structure, the outer diameter of the valve ring is consistent with the inner diameter of the valve seat, and is fixedly arranged inside the valve seat at one end away from the axis of the base pipe; the inner hole of the valve ring forms a movable cavity; the valve seat, guide seat and valve ring of the ICD valve are coaxially arranged to form a guide channel of the ICD valve.

[0008] Furthermore, the flow control unit is a circular ring structure with a second inner hole inside; the flow control unit is arranged in the movable cavity of the valve ring; wherein, the outer diameter of the flow control unit is consistent with the diameter of the movable cavity of the valve ring, and the axial length of the flow control unit is smaller than the axial length of the movable cavity of the valve ring; the flow control unit can move axially in the movable cavity of the valve ring under the action of downhole fluid.

[0009] Furthermore, a top plate is provided at one end of the valve ring away from the guide seat, and a guide hole is provided at a position where the top plate and the upper end surface of the flow control unit axially overlap, and the outer diameter of the guide hole is smaller than the outer diameter of the flow control unit; when the flow control unit is located at the second position, the upper end surface of the flow control unit cooperates with the lower surface of the top plate to close the guide hole, thereby closing the guide channel.

[0010] Furthermore, the diameter of the first inner hole of the flow guide seat is smaller than the outer diameter of the flow control unit.

[0011] Furthermore, a second through hole is provided on the shell at a position corresponding to the axis direction of the ICD valve, and a valve cover is detachably provided in the second through hole; the valve cover is a circular plate-shaped structure, and the diameter of the valve cover is larger than the outer diameter of the valve ring.

[0012] Furthermore, a boss extending inward is provided at one end of the valve seat close to the axis of the base tube, and a recess matching the boss is provided at a position corresponding to the boss at one end of the guide seat close to the axis of the base tube.

[0013] Furthermore, the valve ring is detachably installed inside the valve seat from top to bottom, and the bottom surface of the valve ring abuts against the top surface of the guide seat.

[0014] Furthermore, a positioning ring protruding outward is provided on the outer circumference of the valve seat located outside the base pipe.

[0015] Furthermore, a bursting membrane is sandwiched between the guide seat and the valve ring, and a soluble component is provided in the first inner hole of the guide seat.

[0016] Furthermore, the ICD valve includes a valve seat, a valve ring and a valve cover, wherein the valve seat is a circular ring structure, arranged in the first through hole of the side wall of the base pipe; the valve ring is a circular ring structure, the outer diameter of the valve ring is consistent with the inner diameter of the valve seat, and is fixedly arranged inside the valve seat, and the inner hole of the valve ring forms a movable cavity; the position where the upper part of the valve ring extends out of the side wall of the valve seat is provided with a cross groove penetrating the side wall of the valve ring; the valve cover is detachably arranged on the outer shell at a position corresponding to the axial direction of the ICD valve, the valve cover is a circular structure, and the lower surface is pressed against the upper surface of the valve seat; the valve seat, valve ring and valve cover of the ICD valve are coaxially arranged, and the valve seat, the movable cavity of the valve ring and the cross groove form the diversion channel of the ICD valve.

[0017] Furthermore, the flow control unit is a circular ring structure, which is arranged in the movable cavity of the valve ring; wherein, the outer diameter of the flow control unit is consistent with the diameter of the movable cavity of the valve ring, and the axial length of the flow control unit is smaller than the axial length of the movable cavity of the valve ring; under the action of downhole fluid, the flow control unit can move axially in the movable cavity of the valve ring.

[0018] Furthermore, the axial length of the flow control unit is smaller than the axial length of the moving cavity of the valve ring; wherein, when the flow control unit is located at a first position, the flow control unit is lower than the lowest position of the cross groove; and when the flow control unit is located at a second position, the flow control unit closes the cross groove.

[0019] Furthermore, a bottom plate is provided at one end of the valve ring close to the axis of the base pipe, and a plurality of leakage holes with inconsistent directions are provided on the bottom plate.

[0020] Furthermore, a step structure is provided at the bottom of the movable cavity, and the inner diameter of the truncated cone formed by the step structure is smaller than the outer diameter of the flow control unit and larger than the inner diameter of the flow control unit.

[0021] The present invention discloses a water control screen with anti-backflow function. By setting a flow control unit in the flow guide channel of the ICD valve, it is possible to only allow liquid to flow from the wellbore annulus into the base pipe under positive pressure differential conditions, and not allow liquid to flow out of the base pipe into the wellbore annulus under reverse pressure differential conditions. When it is necessary to open the flow guide channel provided with a sealing device during completion or production, it is only necessary to fill the base pipe with high-pressure fluid to form a reverse bottomhole pressure differential. At this time, the flow guide channel of the ICD valve with the flow control unit is closed, which can prevent the filled fluid from leaking into the wellbore annulus, thereby being very beneficial to establish high pressure in the center pipe column and easily reaching the opening pressure of the sealing device. On the other hand, when the ICD valves of all water control screens 1 are closed, the reverse pressure increase values ​​at different positions in the center pipe column will also tend to be consistent, making it easier to accurately control the reverse bottomhole pressure differential at different positions inside the center pipe column, and it is also easier to generate the expected reverse bottomhole pressure differential at a deeper position in the wellbore. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of a water control screen pipe with a backflow prevention function in an embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of the axial section structure of part I;

[0024] Figure 3 yes Figure 2 Schematic diagram of the open / closed position of the ICD valve in the axial direction;

[0025] Figure 4 yes Figure 2 Schematic diagram of the open / closed position of the ICD valve in the radial direction;

[0026] Figure 5 yes Figure 1 A schematic diagram of the axial section structure of another structure in part I;

[0027] Figure 6 yes Figure 5 Schematic diagram of the open / closed position of the ICD valve in the axial direction;

[0028] Figure 7 yes Figure 1 A schematic diagram of the axial section structure of another structure in part I;

[0029] Figure 8 yes Figure 7Schematic diagram of the open / closed position of the ICD valve in the axial direction;

[0030] Fig. 9 yes Figure 7 Top view of the middle valve ring.

[0031] Explanation of the reference numerals: water control screen-1, base pipe-11, shell-12, screen-121, ICD valve-2, guide seat-21, first inner hole-211, recessed platform-212, valve seat-22, boss-221, positioning ring-222, valve cover-23, countersunk hole-231, extension surface-232, valve ring-24, guide hole-241, movable cavity-242, top plate-243, cross groove-244, bottom plate-245, leakage hole-246, step structure-247, flow control unit-25, second inner hole-251, bursting membrane-3, soluble part-4. DETAILED DESCRIPTION

[0032] The following is combined with Figures 1 to 9 , further illustrating the specific implementation of the water control screen tube with anti-backflow function of the present invention. The water control screen tube with anti-backflow function of the present invention is not limited to the description of the following embodiments.

[0033] Embodiment 1:

[0034] This embodiment provides a specific structure of a water control screen tube 1 with a backflow prevention function, such as Figure 1-4 As shown, the water control screen pipe 1 includes a base pipe 11 and an outer shell 12; wherein the outer shell 12 is a cylindrical structure, coaxially arranged on the circumferential outer side of the base pipe 11, the two ends of the outer shell 12 are sealed and connected to the circumferential outer side of the base pipe 11, and a screen 121 is provided in the middle; an ICD valve 2 is provided at the side wall position of the base pipe 11 covered by the outer shell 12, and the ICD valve 2 includes a diversion channel, and the diversion channel runs through the outside and the inside of the side wall of the base pipe 11; it is characterized in that: a flow control unit 25 is provided in the diversion channel of the ICD valve 2; wherein, when the bottom hole pressure difference is positive, the flow control unit 25 is located in the first position, and does not prevent the fluid in the wellbore annulus from flowing from the outside of the base pipe 11 to the inside of the base pipe 11 through the diversion channel; when the bottom hole pressure difference is reverse, the flow control unit 25 is located in the second position, closing the diversion channel, thereby preventing the fluid in the base pipe 11 from flowing from the inside of the base pipe 11 to the outside of the base pipe 11 through the diversion channel.

[0035] Specifically, the overall shape of the water control screen 1 is consistent with the shape of the central pipe string lowered into the wellbore during the well completion construction process of the prior art, and can be in the form of short sections or long sections. The shell 12 and the screen 121 are used to protect the ICD valve 2 from friction and collision damage to the wellbore wall when it is lowered into the wellbore, and to prevent particles in the wellbore (particles include sand produced from the wellbore, artificially filled gravel, or artificially filled sealing particles into the wellbore annulus based on the "continuous packer water control technology" proposed by the applicant company, see Chinese Patent No. 20 for details) from being damaged. 1910623000X A sealing method and completion structure for injection and production in the same well, 2019104892759 An artificial well wall formation method and completion structure for preventing mud output or crossflow in mudstone layer, 2021111193667 A continuous sealing body for improving the axial anti-crossflow capability in the downhole annulus, 202120468829X Water injection well, 2023113127387 A method for reducing water and increasing oil production by filling sealing body particles in oil and gas wells in fractured oil and gas reservoirs, etc.) flows into the base pipe through the ICD valve 2. The ICD valve 2 is a horizontal well inflow control valve, and one or more ICD valves 2 can be set on each water control screen pipe 1; the diversion channel of the ICD valve 2 is used to divert the production fluid in the wellbore to the base pipe and produce the wellhead. The flow control unit 25 cooperates with the ICD valve to produce a function similar to a "check valve", that is, only allowing the liquid to flow from the wellbore annulus into the base pipe under the condition of positive bottom hole pressure difference, and not allowing the liquid to flow out from the base pipe to the wellbore annulus under the condition of reverse bottom hole pressure difference. By setting the ICD valve 2 with the flow control unit 25, when it is necessary to open the diversion channel provided with the sealing device as described in the background technology section during the completion or production process, it is only necessary to inject high-pressure fluid into the base pipe to form a reverse bottom hole pressure difference. At this time, the diversion channel of the ICD valve 2 with the flow control unit 25 is closed, which can prevent the injected fluid from leaking into the wellbore annulus, thereby being very conducive to establishing the high pressure inside the central pipe column and easily reaching the opening pressure of the sealing device. On the other hand, when the ICD valves of all the water control screens 1 are closed, the reverse pressure increase values ​​at different positions in the central pipe column will also tend to be consistent, making it easier to accurately control the reverse bottom hole pressure difference at different positions inside the central pipe column, and it is also easier to generate the expected reverse bottom hole pressure difference at a deeper position in the wellbore.

[0036] As an optional embodiment, the ICD valve 2 includes a guide seat 21, a valve seat 22 and a valve ring 24, wherein the valve seat 22 is a circular ring structure, arranged in the first through hole on the side wall of the base pipe 11; the guide seat 21 is a circular ring structure, the outer diameter of the guide seat 21 is consistent with the inner diameter of the valve seat 22, and is fixedly arranged inside the valve seat 22 at one end close to the axis of the base pipe 11; the valve ring 24 is a circular ring structure, the outer diameter of the valve ring 24 is consistent with the inner diameter of the valve seat 22, and is fixedly arranged inside the valve seat 22 at one end away from the axis of the base pipe 11; the inner hole of the valve ring 24 forms a movable cavity 242; the valve seat 22, the guide seat 21 and the valve ring 24 of the ICD valve 2 are coaxially arranged to form a guide channel of the ICD valve 2.

[0037] Specifically, the valve seat 22 can be welded on the side wall of the base pipe 11, usually in a fixed installation mode, that is, it will not be disassembled after installation; the valve seat 22, the flow guide seat 21 and the valve ring 24 of the ICD valve 2 can be connected by threading, for example, the valve seat 22 is provided with an internal thread, and the flow guide seat 21 and the valve ring 24 are provided with an external thread, which are connected and fixed with the valve seat 22 by threads. Of course, as a component that needs to be disassembled frequently, the valve ring 24 can also be connected to the valve seat 22 by a clamping method.

[0038] As an optional embodiment, the flow control unit 25 is a circular ring structure with a second inner hole 251 inside; the flow control unit 25 is arranged in the movable cavity 242 of the valve ring 24; wherein, the outer diameter of the flow control unit 25 is consistent with the diameter of the movable cavity 242 of the valve ring 24, and the axial length of the flow control unit 25 is smaller than the axial length of the movable cavity 242 of the valve ring 24; the flow control unit 25 can move axially in the movable cavity 242 of the valve ring 24 under the action of downhole fluid.

[0039] Specifically, Figure 3 , Figure 4 As shown in the left figure, during normal production, there is a positive bottom hole pressure difference. At this time, the flow control unit 25 is located in the first position. Under the action of the positive bottom hole pressure difference P, the production fluid Q flows out from the bottom. When the user fills the central pipe string with high pressure fluid, as shown in FIG. Figure 3 , Figure 4 As shown in the right figure, under the action of the reverse bottom hole pressure difference P, the fluid in the flow guide channel changes direction and drives the flow control unit 25 to move from the first position to the second position.

[0040] As an optional embodiment, a top plate 243 is further provided at one end of the valve ring 24 away from the guide seat 21, and a guide hole 241 is provided at a position where the top plate 243 and the upper end surface of the flow control unit 25 axially overlap, and the outer diameter of the guide hole 241 is smaller than the outer diameter of the flow control unit 25; when the flow control unit 25 is located at the second position, the upper end surface of the flow control unit 25 cooperates with the lower surface of the top plate 243 to close the guide hole 241, thereby closing the guide channel.

[0041] Specifically, the top plate 243 may be integrally formed with the annular portion of the valve ring 24. One or more flow guide holes 241 may be provided, and preferably may be equidistantly distributed along the circumferential direction. The outer diameter of the flow guide hole 241 is smaller than the outer diameter (i.e., the thickness of the annular ring) of the flow control unit 25, thereby ensuring that when the flow control unit 25 moves from the first position to the second position, the upper annular end surface of the flow control unit 25 can completely cover the flow guide hole 241, thereby closing the flow guide hole 241, and then achieving the effect of closing the flow guide channel.

[0042] As an optional implementation, the diameter of the first inner hole 211 of the flow guide seat 21 is smaller than the outer diameter of the flow control unit 25 .

[0043] Specifically, the diameter of the first inner hole 211 of the flow guide seat 21 is designed to be smaller than the outer diameter of the flow control unit 25, in order to support the flow control unit 25 from below and prevent the flow control unit 25 from falling into the base pipe. At the same time, the diameter of the first inner hole 211 of the flow guide seat 21 should not be smaller than the inner diameter of the flow control unit 25, in order to ensure a sufficiently large flow area and ensure the liquid production; and when a reverse bottom hole pressure difference is generated, the reverse bottom hole pressure difference can act on the lower surface of the flow control unit 25, thereby pushing the flow control unit 25 to move upward.

[0044] As an optional embodiment, a second through hole is further provided on the shell 12 at a position corresponding to the axial direction of the ICD valve 2, and a valve cover 23 is detachably provided in the second through hole; the valve cover 23 is a circular plate-shaped structure, and the diameter of the valve cover 23 is larger than the outer diameter of the valve ring 24.

[0045] Specifically, the purpose of designing the valve cover 23 is to provide an operating space for replacing the guide seat 21, the valve ring 24, and the flow control unit 25. Specifically, on the one hand, in order to achieve the predetermined flow control effect, it may be necessary to set the guide seat 21 with different flow areas at different positions, which requires frequently replacing the guide seat 21 with different models; on the second hand, when the valve ring 24 and the flow control unit 25 are worn or damaged, they also need to be replaced; on the third hand, referring to the bursting membrane 3 disclosed in Example 2, when the bursting membrane 3 is exploded, it also needs to be replaced when it is used next time. As required by the above requirements, a maintenance operation space must be provided for these components. Preferably, the valve cover 23 is connected and fixed to the housing 12 by a threaded manner, and the valve cover 23 is also provided with two or more countersunk holes 231, which are convenient for inserting disassembly tools to rotate and operate the valve cover 23. The diameter of the valve cover 23 should be larger than the outer diameters of the flow guide seat 21 , the valve ring 24 , and the flow control unit 25 , so that the flow guide seat 21 , the valve ring 24 , and the flow control unit 25 can be removed from or inserted into the second through hole where the valve cover 23 is located.

[0046] As an optional embodiment, the valve seat 22 has an inwardly extending boss 221 at one end close to the axis of the base tube 11 , and the guide seat 21 has a concave platform 212 matching the boss 221 at a position corresponding to the boss 221 at one end close to the axis of the base tube 11 .

[0047] Specifically, when the flow guide seat 21 is installed, after the concave platform 212 of the flow guide seat 21 is pressed against the convex platform 221 of the valve seat 22, reliable positioning between the two can be achieved.

[0048] As an optional implementation, the valve ring 24 is detachably installed inside the valve seat 22 from top to bottom, and the bottom surface of the valve ring 24 abuts against the top surface of the guide seat 21 .

[0049] Specifically, after the bottom surface of the valve ring 24 abuts against the top surface of the guide seat 21 , the two can form a positioning structure to ensure stable and reliable installation.

[0050] As an optional implementation, the valve seat 22 is provided with a positioning ring 222 protruding outward at the outer circumference of the base pipe 11 .

[0051] Specifically, the valve seat 22 can be fixedly connected to the base pipe 11 by welding or threaded connection. By providing the positioning ring 222, it can be ensured that the valve seat 22 is positioned on the base pipe 11 with an appropriate depth and without tilt, thereby improving the convenience and reliability of component assembly.

[0052] Embodiment 2:

[0053] This embodiment provides a water control screen tube with a backflow prevention function. Figure 5-6 As shown, this embodiment adds a bursting membrane 3 and a soluble part 4 on the basis of the water control screen tube disclosed in Example 1. A bursting membrane 3 is further sandwiched between the guide seat 21 and the valve ring 24, and a soluble part 4 is provided in the first inner hole 211 of the guide seat 21.

[0054] Specifically, the bursting diaphragm 3 is extruded and installed between the guide seat 21 and the valve ring 24. By setting the bursting diaphragm 3, the water control screen with anti-backflow function provided in this embodiment has a pressure opening function, and also has the one-way anti-backflow function described in Example 1. Preferably, the bursting diaphragms 3 installed in the ICD valves at different positions can adopt different models, so that the ICD valves at different positions can be opened in batches in a controllable manner. When the bursting diaphragm 3 bursts, the ICD valve can participate in liquid production. The soluble part 4 can be completely dissolved within a certain period of time (for example, 5 to 7 days) under certain acid-base (pH), temperature (T), and pressure (P) conditions. The purpose of setting the soluble part 4 is to protect the bursting diaphragm 3 from accidental explosion. Specifically, when the "continuous sealing body filling and water control" technical solution is adopted, it is necessary to fill the sealing particles in the wellbore annulus with a fluid with high pressure. The provision of the soluble part 4 can prevent the high-pressure fluid from accidentally bursting the bursting membrane 3, thereby causing the ICD valve to fail and then be unable to perform controllable opening control.

[0055] The working process of the ICD valve of the water control screen tube with anti-backflow function provided in this embodiment is as follows: Figure 5 As shown, see Fig. 9 As shown in the upper left figure, in the initial state, the soluble part 4 can protect the bursting diaphragm 3 and gradually dissolve under the action of the fluid Q; referring to the upper right figure, the reverse bottomhole pressure difference P in the base pipe 12 acts on the bursting diaphragm 3 but does not destroy the bursting diaphragm 3; referring to the lower left figure, the reverse bottomhole pressure difference P in the base pipe 12 acts on the bursting diaphragm 3 and has destroyed the bursting diaphragm 3, at this time, the flow control unit 25 moves upward under the action of pressure or fluid to close the diversion hole 241; referring to the lower right figure, in the positive bottomhole pressure difference P in the wellbore annulus, the produced fluid forms a flow Q through the diversion channel of the ICD valve and flows into the inside of the base pipe 12.

[0056] Embodiment 3:

[0057] This embodiment provides another water control screen tube with anti-backflow function, such as Figure 7-9As shown, the water control screen tube with anti-backflow function provided in Example 1 is different only in the structure of the ICD valve 2. Specifically, the water control screen tube with anti-backflow function in this embodiment includes a valve seat 22, a valve ring 24 and a valve cover 23, wherein the valve seat 22 is a circular ring structure, which is arranged in the first through hole of the side wall of the base pipe 11; the valve ring 24 is a circular ring structure, the outer diameter of the valve ring 24 is consistent with the inner diameter of the valve seat 22, and is fixedly arranged inside the valve seat 22, and the inner hole of the valve ring 24 forms a movable cavity 242; the upper part of the valve ring 24 extends out of the valve seat 22 A cross groove 244 is provided on the side wall, which passes through the side wall of the valve ring 24; the valve cover 23 is detachably arranged on the outer shell 12 at a position corresponding to the axial direction of the ICD valve 2, and the valve cover 23 is a circular structure, and the lower surface is pressed against the upper surface of the valve seat 22; the valve seat 22, valve ring 24 and valve cover 23 of the ICD valve 2 are coaxially arranged, and the valve seat 22, the movable cavity 242 of the valve ring 24 and the cross groove 244 form a guide channel of the ICD valve 2.

[0058] Specifically, the valve seat 22 is consistent with the structure adopted in Example 1, and the inner bottom of the valve seat 22 is also provided with a boss protruding inwardly for positioning the valve ring 24 installed inside. After the valve ring 24 is installed inside the valve seat 22, the lower bottom surface of the valve ring 24 abuts against the boss, thereby improving the reliability of installation and the accuracy of positioning. The valve ring 24 can be detachably connected to the valve seat 22 by means of threads or clamping. The cross groove 244 is a structure of 4 through holes arranged on the side wall of the valve ring 24. Of course, other numbers of through hole structures, such as 1, 3 or 6, etc., can also be used, as long as the flow cross-sectional area requirements required for production are met, which are all equivalent technical solutions. The structure of the valve cover 23 is similar to the valve cover disclosed in Example 1. Preferably, a protruding extension surface 232 is further provided at the center of the lower surface of the valve cover 23. The purpose of providing the extension surface 232 is to prevent the upper surface of the flow control unit 25 from being adsorbed on the lower surface of the valve cover 23 and unable to move downward when the bottom hole pressure difference changes from reverse to forward.

[0059] As an optional embodiment, the flow control unit 25 is a circular ring structure, and is arranged in the movable cavity 242 of the valve ring 24; wherein, the outer diameter of the flow control unit 25 is consistent with the diameter of the movable cavity 242 of the valve ring 24, and the axial length of the flow control unit 25 is smaller than the axial length of the movable cavity 242 of the valve ring 24; the flow control unit 25 can move axially in the movable cavity 242 of the valve ring 24 under the action of downhole fluid.

[0060] Specifically, when the bottom hole pressure difference is positive, such as Figure 8As shown in the left figure, the fluid in the wellbore annulus flows into the base pipe 12 under the action of the bottom hole pressure difference P, thereby pushing the flow control unit 25 to the first position; when the bottom hole pressure difference changes from positive to reverse, as shown in FIG. Figure 8 As shown in the right figure, the fluid in the base pipe 12 pushes the flow control unit 25 upward to the second position under the action of the reverse bottom hole pressure difference P.

[0061] As an optional embodiment, the axial length of the flow control unit 25 is smaller than the axial length of the moving cavity 242 of the valve ring 24; wherein, when the flow control unit 25 is located at the first position, the flow control unit 25 is lower than the lowest position of the cross groove 244; when the flow control unit 25 is located at the second position, the flow control unit 25 closes the cross groove 244.

[0062] Specifically, Figure 8 As shown in the left figure, when the bottom hole pressure difference is positive, the flow control unit 25 is located at the first position. At this time, the upper surface of the flow control unit 25 is lower than the lowest position of the cross groove 244, and will not hinder the fluid from flowing through the cross groove 244; the fluid in the wellbore annulus passes through the cross groove 244, the second inner hole 251 of the flow control unit 25, and the leakage hole 246 of the valve ring 24 in sequence, and flows into the base pipe 12; Figure 8 As shown in the right figure, when the bottom hole pressure difference changes from positive to reverse, the flow control unit 25 moves upward from the first position to the second position, and the side and / or top of the flow control unit 25 closes the cross groove 244 and / or the second inner hole 251, thereby closing the fluid channel of the ICD valve.

[0063] As an optional implementation, a bottom plate 245 is further provided at one end of the valve ring 24 close to the axis of the base pipe 11 , and a plurality of leakage holes 246 with inconsistent directions are provided on the bottom plate 245 .

[0064] Specifically, the purpose of providing the bottom plate and the leakage hole 246 is to change the direction of the fluid entering the base pipe, so as to prevent the fluid from directly impacting the inner wall of the opposite base pipe along the axis direction of the ICD valve, thereby damaging the base pipe. Figure 8 and Fig. 9 As shown, the number of the leakage holes 246 is 6, which are evenly and symmetrically distributed in the circumferential direction. The leakage hole 246 located in the center is arranged along the axis of the ICD valve, and the directions of the 5 leakage holes 246 in the circumference are at a certain angle to the axis of the ICD valve, so as to prevent the leaked fluid from directly impacting the inner wall of the opposite base pipe.

[0065] As an optional implementation, a step structure 247 is provided at the bottom of the movable cavity 242 , and the inner diameter of the truncated cone formed by the step structure 247 is smaller than the outer diameter of the flow control unit 25 and larger than the inner diameter of the flow control unit 25 .

[0066] Specifically, the purpose of providing the step structure 247 is to support the flow control unit 25 from below to prevent the flow control unit 25 from falling into the base pipe and to prevent the lower surface of the flow control unit 25 from directly contacting the bottom plate 245, thereby closing the leakage hole 246.

[0067] The above content is a further detailed description of the patent of the present invention in combination with specific preferred implementation methods, and it cannot be determined that the specific implementation of the patent of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the patent of the present invention belongs, they can also make several simple deductions or substitutions without departing from the concept of the patent of the present invention, which should be regarded as falling within the scope of protection of the patent of the present invention.

Claims

1. A water control screen pipe with anti-backflow function, comprising a base pipe and a shell; wherein: The shell is a cylindrical structure, coaxially arranged on the circumferential outer side of the base pipe, the two ends of the shell are sealed and connected to the circumferential outer side of the base pipe, and a screen is arranged in the middle; an ICD valve is arranged at the side wall of the base pipe covered by the shell, and the ICD valve includes a flow guide channel, which passes through the outside and the inside of the side wall of the base pipe; it is characterized in that: a flow control unit is arranged in the flow guide channel of the ICD valve, wherein, When the bottom hole pressure difference is positive, the flow control unit is located at the first position, and does not prevent the fluid in the wellbore annulus from flowing from the outside of the base pipe into the inside of the base pipe through the flow diversion channel; When the bottom hole pressure difference is reversed, the flow control unit is located at the second position to close the flow diversion channel, thereby preventing the fluid in the base pipe from flowing from the inside of the base pipe to the outside of the base pipe through the flow diversion channel.

2. The water control screen pipe with anti-backflow function according to claim 1, characterized in that: The ICD valve comprises a flow guide seat, a valve seat and a valve ring, wherein: The valve seat is a circular ring structure and is arranged in the first through hole of the side wall of the base pipe; The guide seat is a circular ring structure, the outer diameter of the guide seat is consistent with the inner diameter of the valve seat, and is fixedly arranged inside the valve seat close to one end of the base pipe axis; The valve ring is a circular ring structure, the outer diameter of the valve ring is consistent with the inner diameter of the valve seat, and is fixedly arranged at one end of the valve seat away from the axis of the base pipe; the inner hole of the valve ring forms a moving cavity; The valve seat, the flow guide seat and the valve ring of the ICD valve are coaxially arranged to form a flow guide channel of the ICD valve.

3. The water control screen pipe with backflow prevention function according to claim 2, characterized in that: The flow control unit is a circular ring structure with a second inner hole inside; the flow control unit is arranged in the movable cavity of the valve ring; wherein the outer diameter of the flow control unit is consistent with the diameter of the movable cavity of the valve ring, and the axial length of the flow control unit is smaller than the axial length of the movable cavity of the valve ring; the flow control unit can move axially in the movable cavity of the valve ring under the action of downhole fluid.

4. The water control screen pipe with backflow prevention function according to claim 3, characterized in that: A top plate is also provided at one end of the valve ring away from the guide seat, and a guide hole is provided at a position where the top plate and the upper end surface of the flow control unit axially overlap, and the outer diameter of the guide hole is smaller than the outer diameter of the flow control unit; when the flow control unit is located at the second position, the upper end surface of the flow control unit cooperates with the lower surface of the top plate to close the guide hole, thereby closing the guide channel.

5. The water control screen pipe with anti-backflow function according to claim 4, characterized in that: The diameter of the first inner hole of the flow guide seat is smaller than the outer diameter of the flow control unit.

6. The water control screen pipe with backflow prevention function according to claim 5, characterized in that: A second through hole is also provided on the shell at a position corresponding to the axis direction of the ICD valve, and a valve cover is detachably provided in the second through hole; the valve cover is a circular plate-shaped structure, and the diameter of the valve cover is larger than the outer diameter of the valve ring.

7. The water control screen pipe with backflow prevention function according to claim 2, characterized in that: An end of the valve seat close to the axis of the base tube is provided with a boss extending inwardly, and an end of the flow guide seat close to the axis of the base tube is provided with a concave platform matching the boss at a position corresponding to the boss.

8. The water control screen pipe with backflow prevention function according to claim 7, characterized in that: The valve ring is detachably installed inside the valve seat from top to bottom, and the bottom surface of the valve ring abuts against the top surface of the guide seat.

9. The water control screen pipe with backflow prevention function according to claim 2, characterized in that: The valve seat is provided with a positioning ring protruding outward at the outer circumference of the base pipe.

10. The water control screen pipe with backflow prevention function according to claim 2, characterized in that: A bursting membrane is sandwiched between the guide seat and the valve ring, and a soluble component is disposed in the first inner hole of the guide seat.

11. The water control screen pipe with backflow prevention function according to claim 1, characterized in that: The ICD valve comprises a valve seat, a valve ring and a valve cover, wherein: The valve seat is a circular ring structure and is arranged in the first through hole of the side wall of the base pipe; The valve ring is a circular ring structure, the outer diameter of the valve ring is consistent with the inner diameter of the valve seat, and the valve ring is fixedly arranged inside the valve seat, and the inner hole of the valve ring forms a moving cavity; the position where the upper part of the valve ring protrudes from the side wall of the valve seat is provided with a cross groove penetrating the side wall of the valve ring; The valve cover is detachably arranged on the housing at a position corresponding to the axis direction of the ICD valve, and the valve cover is a circular structure, with a lower surface pressed against the upper surface of the valve seat; The valve seat, valve ring and valve cover of the ICD valve are coaxially arranged, and the valve seat, the moving cavity of the valve ring and the cross groove form a guide channel of the ICD valve.

12. The water control screen pipe with backflow prevention function according to claim 11, characterized in that: The flow control unit is a circular ring structure and is arranged in the moving cavity of the valve ring; wherein, the outer diameter of the flow control unit is consistent with the diameter of the moving cavity of the valve ring, and the axial length of the flow control unit is smaller than the axial length of the moving cavity of the valve ring; under the action of downhole fluid, the flow control unit can move axially in the moving cavity of the valve ring.

13. The water control screen pipe with backflow prevention function according to claim 12, characterized in that: The axial length of the flow control unit is smaller than the axial length of the moving cavity of the valve ring; wherein, When the flow control unit is located at the first position, the flow control unit is lower than the lowest position of the cross slot; When the flow control unit is located at the second position, the flow control unit closes the cross groove.

14. The water control screen pipe with backflow prevention function according to claim 13, characterized in that: A bottom plate is also provided at one end of the valve ring close to the axis of the base pipe, and a plurality of leakage holes with inconsistent directions are provided on the bottom plate.

15. The water control screen pipe with backflow prevention function according to claim 14, characterized in that: A step structure is provided at the bottom of the moving cavity, and the inner diameter of the truncated cone formed by the step structure is smaller than the outer diameter of the flow control unit and larger than the inner diameter of the flow control unit.

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