Sand prevention flow-limiting valve and sand prevention tubular column

Abstract

The utility model discloses a sand prevention flow-limiting valve and a sand prevention pipe column, and relates to the technical field of sand prevention in oil exploitation, the sand prevention flow-limiting valve comprises a valve pipe and a valve ball, a baffle is arranged at the upper end of the inner wall of the valve pipe, the baffle is provided with a baffle hole, a valve seat is arranged on the inner wall of the lower end of the valve pipe, and the upper end face of the valve seat is a ball seat face which is contracted inwards downwards; the valve seat is provided with a large flow passing channel and a small flow limiting channel which are axially through. The large overflowing channel is located at the lowest position of the ball seat face, the valve ball is arranged in the valve pipe, and the valve ball can seal the large overflowing channel in a setting mode. The small flow limiting channel is located on the periphery of the large flow passing channel, and the small flow limiting channel is communicated all the time. The sand blocking device is simple in structure, convenient to install and high in safety, and by means of limiting a liquid flow channel, pressure is built in a shaft, the sand blocking barrier is reinforced, and the filling compactness is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of sand prevention in petroleum exploitation, in particular to a sand prevention flow limiting valve and a sand prevention pipe column. Background Art

[0002] Since the oil production plant was put into development, it has gone through the stages of expanding production capacity, high-speed development, stable production development, and declining production. It has now entered the "deep development stage" of ultra-high water content. Through intensive production and injection, the sand bodies that make up the oil layer have become less strong and sand production has become more serious. It has reached the point where wells cannot be drilled without sand prevention.

[0003] The sand control technology has gone through a process from nothing to something, from little to many, and then to precision. At present, in response to the serious sand production in oil reservoirs, a process and technical measure based on circulating filling sand control has been formed. A wire-wound screen is put into the casing and filling sand is squeezed into the annulus of the oil casing to form a sand barrier. Although good results have been achieved, it was found during the production process that the fluid supply of some wells decreased significantly after circulating filling, and some wells had filling sand in the central pipe of the exploration and flushing, and the test squeezed formation absorption pressure was low, resulting in a loose sand barrier.

[0004] After the construction of some sand control wells was completed, the problem of insufficient fluid supply capacity was found during well production. After rework, it was found that the central pipes of some wells were filled with sand, and the test squeeze formation absorption pressure was low. Through production analysis, it was found that the formation deficit at the blasthole formed by the circulating filling caused the sand barrier to loosen, which was the cause of the decrease in fluid supply. Therefore, there is an urgent need for a device with a simple structure that can reinforce the sand barrier and improve the filling density.

[0005] To strengthen sand barriers and improve packing density, Publication No. CN116696289A discloses a variable-density, heated, self-declogging sand screen suitable for hydrate production. This patent addresses sand control in natural gas hydrate reservoirs by varying the packing density of the sand-retaining medium, addressing the problem of clogging of the sand screen during natural gas hydrate reservoir production. However, this technology is only applicable to natural gas hydrate reservoirs, primarily addressing the problem of sand screen clogging caused by secondary hydrate crystals. It is not applicable to conventional sandstone reservoirs. Currently, this technology suffers from high technical costs, a narrow scope of application, and inability to achieve large-scale application.

[0006] Regarding the improvement of the one-way valve of water injection wells, those skilled in the art have proposed the following patents.

[0007] Announcement No.: CN107401391B, discloses a one-way valve for high-pressure water injection wells in oil fields, including an outer tube, an inner valve and a plug. A water injection pipe is provided on the side wall of the outer tube, and the bottom opening is a water inlet. The inner valve is installed inside the outer tube and is slidably sealed with the inner wall of the outer tube. A water outlet is provided on the side wall of the inner valve, and the water outlet is arranged corresponding to the water injection pipe. The upper part of the plug is screwed to the inner wall of the outer tube, and the lower part of the plug is slidably sealed with the inner wall of the outer tube. A hook device is provided at the center of the bottom of the plug and is connected to the top of the inner valve.

[0008] This existing technology is used to solve the maintenance problem of the one-way valve at the wellhead of a high-pressure water injection well, but cannot be used to reinforce the sand retaining barrier and improve the filling density.

[0009] Publication number: CN107905764A, discloses a check valve for the wellhead of a water injection well. When water injection is stopped, the steel ball is tightly seated on the ball seat under the action of a spring. Some mud, sand and other impurities that enter the check valve are blocked by the central tube plug and will not directly impact and damage the steel ball and the ball seat. Instead, they fall into the lower part of the annular space between the central tube and the outer tube by gravity. When water is injected again, the deposited mud and sand will be carried away by the water flow, thereby playing a role in sand prevention.

[0010] This existing technology is used to increase the service life of the valve ball in the wellhead one-way valve, but cannot be used to reinforce the sand retaining barrier and improve the filling density.

[0011] Announcement No.: CN205558863U discloses a ball-type well-washing blowout preventer valve. When the tubing is lowered, the ball-type well-washing blowout preventer valve is installed at the lower end of the oil pipe. Due to the presence of high-pressure liquid in the well, the valve ball is tightly seated on the ball seat, thereby sealing the inner hole of the tubing; when the tubing is lowered and the well is washed, the high-pressure liquid generated by the high-pressure pump truck is greater than the pressure in the well, which separates the valve ball from the ball seat, and the high-pressure water flows downward along the inner hole of the tubing, the tapered hole of the compression screw sleeve, the ball seat and the baffle with holes, while the valve ball is blocked by the baffle with holes, and the well-washing channel is unobstructed; when the tubing needs to be pulled out after the well is washed, the valve ball is seated on the ball seat under the action of the well pressure, and the high-pressure liquid in the well will not rush up along the inner hole of the tubing, thereby sealing the inner hole of the tubing, so that the tubing can be safely pulled out.

[0012] This existing technology is used in wells to prevent blowouts, but cannot be used to reinforce sand barriers and improve filling density.

[0013] In short, the technical solutions of the above-disclosed technologies, the technical problems to be solved and the beneficial effects produced are all different from those of the present utility model. Regarding the more technical features, technical problems to be solved and the beneficial effects of the present utility model, the above-disclosed technical documents do not provide any technical inspiration. Utility Model Content

[0014] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a sand control flow limiting valve and a sand control pipe string.

[0015] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0016] On the one hand, the utility model provides a sand-proof flow-limiting valve, comprising a valve tube and a valve ball, a baffle being provided at the upper end of the inner wall of the valve tube, the baffle being provided with a baffle hole, a valve seat being provided on the inner wall of the lower end of the valve tube, and the upper end surface of the valve seat being a downwardly inwardly retracted ball seat surface; the valve seat being provided with an axially continuous large flow channel and a small flow-limiting channel; the large flow channel being located at the lowest point of the ball seat surface, the valve ball being provided in the valve tube, and the valve ball being capable of sealing the large flow channel; the small flow-limiting channel being located at the outer periphery of the large flow channel, and the small flow-limiting channel being always connected.

[0017] Furthermore, the baffle is provided with at least two baffle holes, and the small flow-restricting channels are provided with at least two;

[0018] The sum of the diameters of all baffle holes > the diameter of the large flow channel > the sum of the diameters of all small flow-restricting channels.

[0019] Furthermore, the large flow channel and the small flow-restricting channel are both circular holes;

[0020] The axis of the large flow channel coincides with the central axis of the valve seat;

[0021] The small flow-limiting channels are evenly distributed along the circumference of the large flow-through channel.

[0022] Furthermore, the outer wall of the baffle is threadedly connected to the upper end of the inner wall of the valve tube, and the valve seat and the valve tube are integrally arranged.

[0023] Furthermore, the ball seat surface is a conical surface or an arc surface.

[0024] Furthermore, a cross-shaped bracket is provided at the center of the baffle, and the baffle holes are separated by the cross-shaped bracket.

[0025] Furthermore, an upper joint thread is provided at the upper end of the outer wall of the valve tube, and a lower joint thread is provided at the lower end of the outer wall of the valve tube. The upper joint thread is an external thread of the oil pipe, and the lower joint thread is connected to a threaded conversion coupling. The inner wall of the lower end of the threaded conversion coupling is provided with an internal thread of the oil pipe.

[0026] On the second aspect, the utility model provides a sand control pipe string with a sand control and flow limiting valve, including an oil pipe and a casing. The upper ends of the oil pipe and the casing are connected to the wellhead. The wellhead is provided with one through port and two through ports. The one through port is connected to the oil pipe, and the two through ports are connected to the annulus of the oil pipe and the casing. It also includes the sand control and flow limiting valve described in the first aspect; the upper end of the valve pipe is connected to the two through ports, and the lower end of the valve pipe is connected to the pumping equipment, and the pumping equipment is connected to the one through port.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The utility model has a simple structure, is easy to install and has strong safety. By limiting the liquid flow channel, pressure is built up in the wellbore, the sand barrier is strengthened and the filling density is improved.

[0029] 2. The utility model has the advantages of improving filling quality, ensuring sand control effect, extending the effective period of sand control, low cost and easy use, which increases oil production in the production process, is simple and efficient, and at the same time makes the sand control process technology more perfect and has high on-site applicability; after experimental production, the effect is obvious and can be widely promoted and applied in mechanical sand control wells in oil wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural diagram of a sand control and flow limiting valve in the utility model;

[0031] Figure 2 The utility model is a structural schematic diagram of a sand control pipe string provided with a sand control flow limiting valve.

[0032] In the figure: 1. baffle; 2. valve tube; 3. valve ball; 4. small flow restriction channel; 5. threaded conversion coupling; 6. baffle hole; 7. upper joint thread; 8. ball seat surface; 9. large flow passage; 10. lower joint thread; 11. wellhead spool; 12. first port; 13. second port; 14. casing; 15. oil pipe; 16. a sand control and flow restriction valve; 17. pumping equipment. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1:

[0035] See also Figure 1The utility model provides a sand control and flow limiting valve, including a valve tube 2 and a valve ball 3. A baffle 1 is provided at the upper end of the inner wall of the valve tube 2, and the baffle 1 is provided with a baffle hole 6. A valve seat is provided on the inner wall of the lower end of the valve tube 2, and the upper end surface of the valve seat is a downwardly retracted ball seat surface 8. The valve seat is provided with an axially through-going large flow channel 9 and a small flow limiting channel 4. The large flow channel 9 is located at the lowest point of the ball seat surface 8, and the small flow limiting channel 4 is located on the outer periphery of the large flow channel 9. The valve ball 3 is provided in the valve tube 2, and the valve ball 3 can seal the large flow channel 9, and the small flow limiting channel 4 is always connected.

[0036] Specifically, the outer wall of the baffle 1 is threadedly connected to the upper end of the inner wall of the valve tube 2, and the baffle 1 is used to prevent the valve ball from falling out.

[0037] Specifically, the valve seat and the valve tube 2 are integrally arranged.

[0038] Specifically, the baffle 1 is provided with at least two baffle holes 6 , and the small flow-restricting channels 4 are provided with at least two. The sum of the diameters of all baffle holes 6 is greater than the diameter of the large flow channel 9 and greater than the sum of the diameters of all small flow-restricting channels 4 .

[0039] Specifically, the large flow channel 9 and the small flow restriction channel 4 are both circular holes, the axis of the large flow channel 9 coincides with the central axis of the valve seat, and the small flow restriction channels 4 are evenly distributed along the circumference of the large flow channel 9 .

[0040] Specifically, the center of the baffle 1 is a cross-shaped bracket, and four baffle holes 6 are separated by the cross-shaped bracket.

[0041] Preferably, the ball seat surface 8 is a conical surface or an arc surface.

[0042] Specifically, an upper joint thread 7 is provided at the upper end of the outer wall of the valve tube 2, and a lower joint thread 10 is provided at the lower end of the outer wall of the valve tube 2. The upper joint thread 7 is an external thread of the oil pipe, and the lower joint thread 10 is connected to the thread conversion coupling 5. The inner wall of the lower end of the thread conversion coupling 5 is provided with an internal thread of the oil pipe.

[0043] Example 2:

[0044] Based on Example 1, Figure 2 , this embodiment provides an application of a sand control flow limiting valve in a sand control pipe string.

[0045] The sand control pipe string includes an oil pipe 15 and a casing 14. The upper ends of the oil pipe 15 and the casing 14 are connected to the wellhead spool 11. The wellhead spool 11 is provided with a single port 12 and two ports 13. The single port 12 is connected to the oil pipe 15, and the two ports 13 are connected to the annulus of the oil pipe 15 and the casing 14. The upper joint thread 7 of the sand control flow limiting valve 16 is connected to the two ports 13, the threaded conversion coupling 5 is connected to the pumping equipment 17, and the pumping equipment 17 is connected to the single port 12.

[0046] The pumping equipment 17 includes a large ground tank and a pump truck.

[0047] During positive circulation, high displacement construction is maintained, the small flow restriction channel 4 limits the flow of liquid, and pressure is generated. The blasthole filling coefficient is increased through pressurized filling to ensure the filling density.

[0048] It should be noted that the sand control string itself is an existing technology, and its structure is known to those skilled in the art, such as announcement number: CN111396008B, which discloses a small-diameter layered sand control water injection full-well backwashing integrated string and method; the pumping equipment 17 itself is an existing technology, and its structure is known to those skilled in the art, such as announcement number: CN210622739U, which discloses a forward and backwashing well reversing device.

[0049] Example 3:

[0050] Based on Example 2, this example provides a method for using a sand control flow limiting valve in a sand control string:

[0051] The diameter of the valve ball 3 is 40mm, the diameter of the large flow channel 9 is 30mm, four small flow limiting channels 4 are set, the diameter of the small flow limiting channels 4 is 5mm, the inner diameter of the baffle 1 is 38mm, and there is a cross-shaped bracket in the middle of the baffle 1 to block the valve ball 3.

[0052] When in use, a sand control and flow limiting valve 16 is installed on the ground in the connection manner described in Example 2, and is added between the wellhead spool 11 and the pumping equipment 17.

[0053] After the valve pipe 2 is installed on the ground, the valve ball 3 inside is in a free state.

[0054] During construction, the pump truck injects the filling material into the wellbore through the oil pipe 15 for positive circulation filling. The well fluid returns from the annulus of the oil pipe 15 and the casing 14 to the second port 13 of the wellhead four-way 11. The valve ball 3 sits on the ball seat surface 8 under the action of the well fluid, blocking the large flow channel 9, allowing the well fluid to flow through the surrounding small flow-restricting channel 4 with increased pressure and increasing the pressure in the wellbore. After the well fluid flows into the threaded conversion coupling 5, it enters the large tank on the ground through the pipeline, and is injected into the well after adding the filling material, realizing the continuous circulation sand prevention filling construction; the sand barrier is reinforced by pressure through the small flow-restricting channel 4, and the blasthole filling coefficient is increased by pressure filling to ensure the filling density.

[0055] When backwashing the well after construction is completed, the well-washing water is injected into the threaded conversion coupling 5 through the pump truck, and pushes the valve ball 3 through the large flow channel 9 to flow to the baffle 1. At this time, the valve ball 3 sits on the cross-shaped bracket of the baffle 1. The well-washing water flows through the baffle hole 6 to the second port 13 of the wellhead cross 11, enters the annulus of the oil pipe 15 and the casing 14, and finally flows out from the first port 12 to the large tank on the ground, realizing the circulation backwashing of the well.

[0056] After on-site experimental application, the experimental wells all achieved a filling sand volume higher than the theoretical sand volume. By adopting a flow limiting valve to improve the filling density, the process has been applied to 8 wells, with a cumulative oil production of 4,098.5 tons and a cumulative economic benefit of 9.631 million yuan. It is expected that the oil production plant will promote the application to 30 wells per year, with an estimated cumulative oil production of 15,000 tons and an estimated economic benefit of 36.116 million yuan.

[0057] All components not discussed in detail in this application and the connection methods of the components in this application are well-known technologies in the technical field and can be directly applied without further explanation.

[0058] In this utility model, the term "plurality" refers to two or more, unless otherwise specified. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean fixed, removable, or integral; "connected" can mean directly or indirectly through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0059] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0060] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A sand control and flow limiting valve, comprising a valve tube and a valve ball, wherein a baffle is provided on the upper end of the inner wall of the valve tube, the baffle being provided with a baffle hole, and a valve seat is provided on the inner wall of the lower end of the valve tube, characterized in that: The upper end surface of the valve seat is a spherical seat surface that is retracted downward; The valve seat is provided with a large flow passage and a small flow restriction passage which are axially connected; The large flow passage is located at the lowest point of the ball seat surface, and the valve ball is arranged in the valve tube, and the valve ball can seal the large flow passage; The small flow-restricting channel is located on the periphery of the large flow-through channel, and the small flow-restricting channel is always connected.

2. A sand control and flow limiting valve according to claim 1, characterized in that: The baffle is provided with at least two baffle holes, and the small flow-limiting channels are provided with at least two; The sum of the diameters of all baffle holes > the diameter of the large flow channel > the sum of the diameters of all small flow-restricting channels.

3. A sand control and flow limiting valve according to claim 2, characterized in that: The large flow passage and the small flow-limiting passage are both circular holes; The axis of the large flow channel coincides with the central axis of the valve seat; The small flow-limiting channels are evenly distributed along the circumference of the large flow-through channel.

4. The sand control and flow limiting valve according to claim 1, characterized in that: The outer wall of the baffle is threadedly connected to the upper end of the inner wall of the valve pipe, and the valve seat and the valve pipe are arranged as one body.

5. The sand control and flow limiting valve according to claim 1, characterized in that: The ball seat surface is a conical surface or an arc surface.

6. The sand control and flow limiting valve according to claim 1, characterized in that: A cross-shaped bracket is provided at the center of the baffle, and the baffle holes are separated by the cross-shaped bracket.

7. The sand control and flow limiting valve according to claim 1, characterized in that: The upper end of the outer wall of the valve pipe is provided with an upper joint thread, and the lower end of the outer wall of the valve pipe is provided with a lower joint thread. The upper joint thread is an external thread of the oil pipe, and the lower joint thread is connected to a threaded conversion coupling. The inner wall of the lower end of the threaded conversion coupling is provided with an internal thread of the oil pipe.

8. A sand control string with a sand control flow limiting valve, comprising an oil pipe and a casing, wherein the upper ends of the oil pipe and the casing are connected to a wellhead, and the wellhead is provided with a first opening and a second opening, wherein the first opening is connected to the oil pipe, and the second opening is connected to the annulus of the oil pipe and the casing, characterized in that: Also includes a sand control and flow limiting valve according to claim 1; The upper end of the valve pipe is connected to the second port, the lower end of the valve pipe is connected to the pumping device, and the pumping device is connected to the first port.

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