Impact type self-cleaning sand control device

Abstract

The application discloses an impact self-cleaning sand prevention device, which comprises a coupling, a sand filter pipe, a variable-diameter piston assembly, a central pipe and an impact vibrator. The top end of the coupling is connected with a sucker rod string, the bottom end of the coupling is connected with the top end of the sand filter pipe, the bottom end of the sand filter pipe is connected with the top end of the central pipe, and the bottom end of the central pipe is connected with the top end of the impact vibrator. The variable-diameter piston assembly is connected to the outer wall of the central pipe. The impact self-cleaning sand prevention device can continuously and timely remove the blockage of the sand filter pipe during the extension and retraction of the sucker rod string in the upstroke and downstroke of the oil pump, so that the permeability of the sand filter pipe is maintained.

Description

Technical Field

[0001] This invention belongs to the field of oil production engineering and relates to a sand filtering device that removes blockage of the sand filter pipe by feedback fluid flow, specifically an impact-type self-cleaning sand prevention device. Background Technology

[0002] Currently, common sand control methods in oil wells include mechanical and chemical sand control. Mechanical sand control methods mainly include sand control with various types of filter pipes under the pump and sand control with gravel packing outside the filter pipe. Regardless of the type of mechanical sand control, it will ultimately lead to a reduction in the permeability of the sand control structure, affecting oil well production. At present, there is no feasible technical solution to the problem of filter pipe clogging under the pump. Technicians are accustomed to improving the filter pipe structure to enhance its sand filtering effect and reduce the possibility of damage to its permeability, but this does not fundamentally solve the problem. Summary of the Invention

[0003] To address the problem of clogging in the filter sand pipe under the pump, this invention provides an impact-type self-cleaning sand-prevention device that can continuously and in real-time remove blockages from the filter sand pipe by extending and retracting the oil tubing during the up and down strokes of the oil pump, thus maintaining its permeability.

[0004] The technical solution adopted by the present invention to solve its technical problem is: an impact-type self-cleaning sand-proof device, including a coupling, a filter pipe, a variable diameter piston assembly, a central pipe, and an impact vibrator. The top end of the coupling is connected to the oil extraction tubing string, and the bottom end is connected to the top end of the filter pipe. The bottom end of the filter pipe is connected to the top end of the central pipe, and the bottom end of the central pipe is connected to the top end of the impact vibrator. The variable diameter piston assembly is connected to the outer wall of the central pipe.

[0005] As a further embodiment of the present invention, the variable diameter piston assembly includes an upper fixed sleeve, a variable diameter piston valve seat, a variable diameter piston body, a bridging limiting sleeve, a variable diameter piston valve ball, and a lower fixed sleeve; the variable diameter piston body is fixedly connected to the outer wall of the central tube by fixing pins; the upper fixed sleeve, the bridging limiting sleeve, and the lower fixed sleeve are respectively connected to the outer wall of the variable diameter piston body; the variable diameter piston valve seat is located on the outside of the variable diameter piston body and is fixed by the upper fixed sleeve and the bridging limiting sleeve; the variable diameter piston valve ball is located on the outside of the variable diameter piston body and below the variable diameter piston valve seat, and is fixed by the lower fixed sleeve and the bridging limiting sleeve.

[0006] As a further embodiment of the present invention, the variable diameter piston body has three large-diameter sections spaced apart, with a small-diameter section between each two adjacent large-diameter sections; the three large-diameter sections are connected to the upper fixed sleeve, the bridging limiting sleeve, and the lower fixed sleeve from top to bottom, respectively; milled grooves are evenly distributed on the three large-diameter sections, and the bottom of the milled grooves is at the same height as the small-diameter sections; the variable diameter piston valve ball can slide relative to each other in the milled grooves.

[0007] As a further embodiment of the present invention, the variable diameter piston valve seat is welded together from two parts: a variable diameter piston and a valve seat. A groove is provided on the inner side of the variable diameter piston, and a reset spring a is installed in the groove.

[0008] As a further embodiment of the present invention, a groove is provided on the inner side of the variable diameter piston valve ball, and a reset spring b is installed in the groove.

[0009] As a further embodiment of the present invention, the impact vibrator includes a vibrator pump cylinder, a vibrator piston, a vibrator connecting rod, a vibrator limiting sleeve, and a counterweight joint; the upper end of the vibrator pump cylinder is connected to the bottom end of the central tube, and the lower end of the vibrator pump cylinder is connected to the vibrator limiting sleeve; the vibrator piston is slidably connected inside the vibrator pump cylinder, and a boss is provided on the inner wall of the vibrator pump cylinder to limit the maximum upward position of the vibrator piston; the lower end of the vibrator piston is connected to the vibrator connecting rod, and the lower end of the vibrator connecting rod is connected to the counterweight joint.

[0010] As a further embodiment of the present invention, the outer surface of the vibrator piston is provided with a plurality of sand-proof grooves.

[0011] As a further embodiment of the present invention, the vibrator limiting sleeve has a stepped inner diameter, and several through holes are provided at the steps.

[0012] The beneficial effects of this invention include: The impact-type self-cleaning sand control device provided by this invention uses the extension and retraction of the sucker tubing during the up and down strokes of the oil pump to drive the vibrator piston to strike the vibrator pump barrel, generating up and down vibration and pressure fluctuations. This continuously and in real time removes the blockage of the filter sand tube by mud cake and other materials, thereby maintaining the permeability of the filter sand tube and facilitating normal oil well production. During backwashing, due to the throttling effect of the variable-diameter piston, a pressure difference can be established inside and outside the filter sand tube, forcibly removing the blockage in the filter sand tube in the reverse direction. Attached Figure Description

[0013] To illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the overall structure of an impact-type self-cleaning sand-proof device according to the present invention;

[0015] Figure 2 This is a cross-sectional view (AA) of the oil pump descending.

[0016] Figure 3 This is a cross-sectional view (AA) of the oil pump's upward movement.

[0017] The following are the labels in the attached diagram: 1-coupling, 2-sand filter pipe, 3-variable diameter piston assembly, 4-center pipe, 5-impact vibrator;

[0018] 3-1-Upper fixed sleeve, 3-2-Variable diameter piston valve seat, 3-3-Reset spring a, 3-4-Variable diameter piston body, 3-5-Bridge limiting sleeve, 3-6-Variable diameter piston valve ball, 3-7-Reset spring b, 3-8-Lower fixed sleeve, 3-9-Variable diameter piston, 3-10-Valve seat;

[0019] 4-1-Fixing pin, 5-1-Vibrator pump cylinder, 5-2-Vibrator piston, 5-3-Sandproof groove, 5-4-Vibrator connecting rod, 5-5-Vibrator limiting sleeve, 5-6-Through hole, 5-7-Counterweight joint. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used only to distinguish components and should not be construed as indicating or implying relative importance.

[0022] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Example 1

[0024] An impact-type self-cleaning sand-proof device can continuously and in real time remove blockages from the filter pipe 2 by extending and retracting the oil extraction tubing, thus maintaining its permeability.

[0025] It includes a coupling 1, a filter pipe 2, a variable diameter piston assembly 3, a central pipe 4, and an impact vibrator 5. The top end of the coupling 1 is threaded to the oil sucker tubing, the bottom end of the coupling 1 is threaded to the top end of the filter pipe 2, the bottom end of the filter pipe 2 is threaded to the top end of the central pipe 4, the bottom end of the central pipe 4 is threaded to the top end of the impact vibrator 5, and the variable diameter piston assembly 3 is connected to the outer wall of the central pipe 4.

[0026] The variable diameter piston assembly 3 includes an upper fixed sleeve 3-1, a variable diameter piston valve seat 3-2, a variable diameter piston body 3-4, a bridging limiting sleeve 3-5, a variable diameter piston valve ball 3-6, and a lower fixed sleeve 3-8.

[0027] The variable-diameter piston body 3-4 is fixedly connected to the outer wall of the central tube 4 by fixing pins 4-1. The variable-diameter piston body 3-4 consists of three large-diameter sections and several small-diameter sections. The three large-diameter sections are spaced apart, with a small-diameter section between every two adjacent large-diameter sections. All three large-diameter sections are threaded, and from top to bottom, they are named the first large-diameter section, the second large-diameter section, and the third large-diameter section.

[0028] In the above implementation scheme, the outer wall of the first large-diameter section is connected to the inner wall of the upper fixing sleeve 3-1, the outer wall of the second large-diameter section is connected to the inner wall of the bridging limiting sleeve 3-5, and the outer wall of the third large-diameter section is connected to the inner wall of the lower fixing sleeve 3-8. In the threaded section, i.e., the three large-diameter sections, milled grooves are evenly distributed, with the bottom of the milled grooves at the same height as the smaller diameter sections. Specifically, the first large-diameter section and half the length of the second large-diameter section have milled grooves with the same phase angle, and the third large-diameter section and the other half of the second large-diameter section have milled grooves with the same phase angle. The milled grooves of the first and third large-diameter sections are distributed at a certain phase angle, i.e., the milled groove of the first large-diameter section corresponds to the boss of the third large-diameter section, and the milled groove of the third large-diameter section corresponds to the boss of the first large-diameter section.

[0029] The variable diameter piston valve seat 3-2 is located on the outside of the variable diameter piston body 3-4 and is fixed by the upper fixing sleeve 3-1 and the bridging limiting sleeve 3-5, which limit its axial position and maximum and minimum diameters. The variable diameter piston valve seat 3-2 is welded together from two parts: the variable diameter piston assembly 3-9 and the valve seat 3-10. Both ends are provided with chamfers at a certain angle. Its prefabricated outer diameter is the same as the sleeve size, and its number and width are the same as the number and width of the milled grooves in the large diameter section. A groove is opened on the inner side of the variable diameter piston assembly 3-9, and a return spring a3-3 is installed in the groove. The variable diameter piston valve seat 3-2 is supported and fixed to each other by the return spring 3-3.

[0030] The variable diameter piston valve ball 3-6 is located outside the variable diameter piston body 3-4 and below the variable diameter piston valve seat 3-2. It is fixed by the lower fixing sleeve 3-8 and the bridging limiting sleeve 3-5, which limit its axial position and maximum and minimum diameters. Both ends of the variable diameter piston valve ball 3-6 are chamfered at a certain angle. Its prefabricated outer diameter is the same as the sleeve size, and its number and width are the same as the number and width of the milled grooves in the large diameter section. A groove is formed on the inner side of the variable diameter piston valve ball 3-6, and a return spring b3-7 is installed in the groove. The variable diameter piston valve ball 3-6 is supported and fixed to each other by the return spring b3-7.

[0031] The variable diameter piston valve ball 3-6 is set with a certain amount of axial displacement; the variable diameter piston valve ball 3-6 can move upward a certain distance in the milling groove, forming a complete cylinder together with the variable diameter piston valve seat 3-2 to form a sealing pair with the sleeve, while keeping the variable diameter piston valve ball 3-6 in the closed state; the variable diameter piston valve ball 3-6 can move downward a certain distance in the milling groove, increasing the distance with the variable diameter piston valve seat 3-2, keeping the variable diameter piston valve ball 3-6 in the open state.

[0032] The impact vibrator 5 includes a vibrator pump cylinder 5-1, a vibrator piston 5-2, a vibrator connecting rod 5-4, a vibrator limiting sleeve 5-5, and a counterweight joint 5-7.

[0033] The upper end of the vibrator pump cylinder 5-1 is threaded for connection to the bottom end of the central tube 4, and the lower end of the vibrator pump cylinder 5-1 is threaded for connection to the vibrator limiting sleeve 5-5. The inner diameter of the vibrator pump cylinder 5-1 is machined into a stepped inner circle. The larger inner circle portion slides in contact with the vibrator piston 5-2, and the smaller inner circle step is used to limit the maximum upward position of the vibrator piston 5-2. The upper part of the vibrator piston 5-2 is cylindrical, and the lower end is threaded, with the threaded part connecting to the vibrator connecting rod 5-4. Several sand-proof grooves 5-3 are formed on the outer surface of the vibrator piston 5-2. The vibrator connecting rod 5-4 is threaded at both ends. The upper threaded part connects to the vibrator piston 5-2, and the lower threaded part connects to the counterweight joint 5-7. The vibrator limiting sleeve 5-5 is machined into a stepped inner diameter. The upper end is threaded to connect with the vibrator pump cylinder 5-1, and the lower end has several symmetrical through holes 5-6 at the stepped part for pressure relief. At the same time, the stepped part can limit the maximum downward position of the vibrator piston 5-2.

[0034] During operation, the oil pump descends, and the sucker tubing extends instantaneously under hydraulic pressure, driving the fixed sleeve 3-1, variable diameter piston valve seat 3-2, return spring a3-3, variable diameter piston body 3-4, and bridging limit sleeve 3-5 of the variable diameter piston assembly 3 to descend. At this time, the variable diameter piston valve ball 3-6, under the action of the return spring b3-7, has a certain frictional force with the sleeve, keeping it relatively stationary with the sleeve, and slides a certain distance relative to the milled groove of the variable diameter piston body 3-4, forming a section overlap with the variable diameter piston valve seat 3-2, and intersecting with it. The overlapping and intersecting sections together form a complete cylinder, forming a sealing pair with the sleeve, and at the same time, the variable diameter piston valve ball 3-6 is in the closed state, forming a relative seal on the liquid below the variable diameter piston assembly 3. As the tubing string rapidly extends downwards, a high-pressure zone is formed in the wellbore below the variable-diameter piston assembly 3. Under this high pressure, the vibrator piston 5-2 rapidly rises, creating high pressure within the filter pipe 2 and the central pipe 4. The high-pressure liquid impacts the filter pipe 2, clearing blockages such as mud cake from its outer wall and thus unblocking it. When the vibrator piston 5-2 reaches its upper jamming point, it strikes the stepped section of the vibrator pump cylinder 5-1, generating an upward vibration that loosens and dislodges the blockages in the filter pipe 2.

[0035] When the oil pump starts to move upward, the hydraulic pressure acting in the oil tubing suddenly disappears, the tubing retracts, and drives the fixed sleeve 3-1, the variable diameter piston valve seat 3-2, the return spring a3-3, the variable diameter piston body 3-4, and the bridging limit sleeve 3-5 on the accessories of the variable diameter piston assembly 3 to move upward. At this time, under the action of the return spring b3-7, the variable diameter piston valve ball 3-6 has a certain frictional force with the sleeve, keeps it relatively stationary with the sleeve, and slides a certain distance relative to the groove of the variable diameter piston body 3-4, pulling it away from the variable diameter piston valve seat 3-2, releasing the mutual crossing with the variable diameter piston valve seat 3-2, and releasing the sealing pair with the sleeve. At the same time, the variable diameter piston valve ball 3-6 is in the open state, making the upper and lower hydraulic pressures of the variable diameter piston assembly 3 the same. Therefore, the upper and lower pressures of the vibrator piston 5-2 are the same. At the same time, under the action of the counterweight connected by the counterweight joint 5-7, the vibrator piston 5-2 quickly moves downward, striking the inner diameter step of the vibrator limiting sleeve 5-5, completing one downward vibration. The striking vibration loosens and dislodges the blockage in the filter sand tube 2, and at the same time, the liquid is discharged and depressurized through the through hole 5-6 at the inner step of the vibrator limiting sleeve 5-5.

[0036] The oil pump enters the next stroke, vibrating up and down repeatedly.

[0037] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An impact-type self-cleaning sand-prevention device, characterized in that, It includes a coupling (1), a filter pipe (2), a variable diameter piston assembly (3), a central pipe (4), and an impact vibrator (5). The top end of the coupling (1) is connected to the oil sucker string, and the bottom end is connected to the top end of the filter pipe (2). The bottom end of the filter pipe (2) is connected to the top end of the central pipe (4), and the bottom end of the central pipe (4) is connected to the top end of the impact vibrator (5). The variable diameter piston assembly (3) is connected to the outer wall of the central pipe (4). The variable diameter piston assembly (3) includes an upper fixed sleeve (3-1), a variable diameter piston valve seat (3-2), a variable diameter piston body (3-4), a bridging limiting sleeve (3-5), a variable diameter piston valve ball (3-6), and a lower fixed sleeve (3-8). The variable diameter piston body (3-4) is fixedly connected to the outer wall of the central tube (4) by a fixing pin (4-1). The upper fixed sleeve (3-1), the bridging limiting sleeve (3-5), and the lower fixed sleeve (3-8) are respectively connected to the outer wall of the variable diameter piston body (3-4). The variable diameter piston valve seat (3-2) is located outside the variable diameter piston body (3-4) and is fixed by the upper fixed sleeve (3-1) and the bridging limiting sleeve (3-5). The variable diameter piston valve ball (3-6) is located outside the variable diameter piston body (3-4) and below the variable diameter piston valve seat (3-2), and is fixed by the lower fixed sleeve (3-8) and the bridging limiting sleeve (3-5). The variable diameter piston body (3-4) has three large-diameter sections spaced apart, with a small-diameter section between each two adjacent large-diameter sections; the three large-diameter sections are connected from top to bottom to the upper fixed sleeve (3-1), the bridging limiting sleeve (3-5), and the lower fixed sleeve (3-8); the three large-diameter sections are evenly distributed with milled grooves, and the bottom of the milled grooves is at the same height as the small-diameter sections; the variable diameter piston valve ball (3-6) can slide relative to the other side within the milled grooves; The impact vibrator (5) includes a vibrator pump cylinder (5-1), a vibrator piston (5-2), a vibrator connecting rod (5-4), a vibrator limiting sleeve (5-5), and a counterweight joint (5-7). The upper end of the vibrator pump cylinder (5-1) is connected to the bottom end of the central tube (4), and the lower end of the vibrator pump cylinder (5-1) is connected to the vibrator limiting sleeve (5-5). The vibrator piston (5-2) is slidably connected inside the vibrator pump cylinder (5-1), and the inner wall of the vibrator pump cylinder (5-1) is provided with a boss to limit the maximum upward position of the vibrator piston (5-2). The lower end of the vibrator piston (5-2) is connected to the vibrator connecting rod (5-4), and the lower end of the vibrator connecting rod (5-4) is connected to the counterweight joint (5-7).

2. The impact-type self-cleaning sand-prevention device according to claim 1, characterized in that, The variable diameter piston valve seat (3-2) is welded together from two parts: the variable diameter piston (3-9) and the valve seat (3-10). The variable diameter piston (3-9) has a groove on its inner side, and a return spring a (3-3) is installed in the groove.

3. The impact-type self-cleaning sand-prevention device according to claim 1, characterized in that, A groove is provided on the inner side of the variable diameter piston valve ball (3-6), and a return spring b (3-7) is installed in the groove.

4. The impact-type self-cleaning sand-prevention device according to claim 1, characterized in that, The outer surface of the vibrator piston (5-2) is provided with several sand-proof grooves (5-3).

5. The impact-type self-cleaning sand-prevention device according to claim 1, characterized in that, The vibrator limiting sleeve (5-5) has a stepped inner diameter, and several through holes (5-6) are opened at the steps.

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