Sand prevention tubular column and using method thereof

Abstract

The invention relates to the technical field of oil field machinery sand prevention, in particular to a sand prevention pipe column and a using method thereof.The sand prevention pipe column comprises an upper connector, a base pipe and a suspension connector which are sequentially and fixedly installed together from top to bottom, and a plurality of through holes penetrating through the inside and the outside are distributed in the outer side of the base pipe in a staggered mode. The through holes in the outer side of the base pipe are distributed in a staggered mode, so that the strength of the base pipe can be guaranteed, the through holes can serve as formation fluid channels, and the screen pipe is convenient to clean; when the shear pin is lifted and lowered after the shear pin is cut off, the upper connector is connected with the base tube to drive the suspension connector to do relative up-down reciprocating motion in the bearing cylinder. The size of the sand prevention hole of the screen pipe can be changed by the relative up-down reciprocating motion of the suspension joint, and the size of the sand prevention hole of the screen pipe can be increased by lifting the upper joint, so that formation sand blocked at a liquid inlet channel can be cleared away during well washing.

Description

Technical Field

[0001] This invention relates to the field of oilfield mechanical sand control technology, specifically a sand control tubing string and its application method. Background Technology

[0002] Permian heavy oil reservoirs are dominated by mudstone, sandstone, and conglomerate, and are prone to sand production during production. Mechanical sand control is a common measure to prevent formation sand production. However, mechanical sand control in heavy oil blocks frequently results in rapid production reduction and insufficient formation fluid supply after sand control. Furthermore, gas injection measures during heavy oil production are prone to corrosion of screen pipes, leading to screen pipe damage and sand control failure. The short effective period of sand control seriously affects oilfield production.

[0003] Formation sand particles are classified into three types: coarse sand, fine sand, and silt. The particle size of sand produced by a single well varies greatly in different regions. A single sand-blocking precision screen pipe cannot meet the precise sand control requirements of different blocks. Furthermore, the phenomenon of oil encapsulation in heavy oil wells can easily clog the fluid inlet channel of the screen pipe, leading to reduced production capacity or even production stoppage. Summary of the Invention

[0004] This invention provides a sand control tubing string and its usage method, overcoming the shortcomings of the prior art. It can effectively solve the problems that existing screen pipes do not meet the precise sand control requirements of different blocks, and that the oil-sand phenomenon in heavy oil wells easily blocks the fluid inlet channel of the screen pipe, leading to reduced production capacity or even production stoppage.

[0005] One of the technical solutions of the present invention is achieved through the following measures: a sand-proof pipe column, comprising an upper connector, a base pipe, and a suspension connector fixedly installed together from top to bottom. The base pipe has several through holes that are intersected and connected internally and externally distributed on its outer side. A bearing cylinder is fitted on the outer side of the suspension connector. Several radially connected external mounting holes are evenly distributed along the circumference on the upper outer side of the bearing cylinder. The upper outer side of the suspension connector corresponding to each external mounting hole position is provided with an outwardly opening internal mounting hole. Each external mounting hole is provided with a shear pin whose end is installed in the corresponding internal mounting hole. A screen pipe is fitted on the outer side of the base pipe. The screen pipe has strip-shaped sand-proof holes that are interconnected internally and externally on its outer side. A lower locking sleeve fitted on the outer side of the suspension connector is provided at the upper end of the bearing cylinder. An upper locking sleeve screwed to the lower outer side of the upper connector is provided at the upper end of the base pipe. When the upper locking sleeve is tightened, it presses the upper end of the screen pipe and makes the sand-proof holes smaller. When the upper locking sleeve is loosened, the screen pipe and sand-proof holes can be reset.

[0006] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The aforementioned screen tube can be a trapezoidal cross-section cylindrical helical compression spring, with sand-proof holes formed between each two adjacent turns of the compression spring.

[0007] The inner side of the aforementioned sieve tube may be provided with a support frame fitted onto the outer side of the base tube. The support frame is a cylindrical shape with a hollow center. Several connecting screws with their ends fixed to the outer side of the base tube are evenly distributed along the circumference on both the upper and lower outer sides of the support frame.

[0008] The surface of the aforementioned screen tube may be provided with an anti-corrosion layer.

[0009] The lower end of the upper locking sleeve can be in sealed contact with the upper end of the screen tube, the upper end of the lower locking sleeve is fixedly installed together with the lower end of the screen tube, the lower end of the lower locking sleeve is in sealed contact with the upper end of the bearing cylinder, and a first sealing ring is provided between the inner side of the lower end of the lower locking sleeve and the outer side of the upper part of the suspension joint.

[0010] A second sealing ring may be provided between the inner side of the aforementioned external mounting hole and the outer side of the shear pin.

[0011] A limiting step may be provided inside the bearing cylinder at the position below the aforementioned shear pin. A retaining ring fitted inside the bearing cylinder is screwed onto the outer side of the lower end of the suspension joint. A lower connector is fixedly installed at the lower end of the bearing cylinder at the position below the retaining ring.

[0012] A packer can be fixedly installed at the lower end of the aforementioned lower connector.

[0013] The second technical solution of the present invention is achieved through the following measures: a method for using a sand-control pipe column, comprising the following steps: S1. Assemble the sand control pipe string, tighten the upper locking sleeve according to the sand discharge characteristics of the formation, and adjust the size of the sand control hole; S2, connect the upper connector to the pipe string, and install the packer at the lower end of the bearing cylinder; S3, lower the sand control tubing string into the target position inside the well; S4, set the packer, and then start production. If the liquid production rate does not decrease during the production cycle, continue production; if the liquid production rate decreases or production stops during the production cycle, proceed with the following steps: S41, by applying downward pressure to the sand control string at the wellhead using the workover equipment, the shear pins are cut off, the bearing cylinder moves downward relative to the suspension joint, and the sand control hole becomes larger; S42, lift the tube to a certain distance; S43, a certain volume of workover fluid is pumped into the upper end of the tubing string through a pumping device at the wellhead; S44, after the formation sand stuck in the sand control hole is flushed and carried to the wellhead by the workover fluid, the workover equipment is used to lower the pipe string, the supporting cylinder moves upward relative to the suspension joint, and the screen pipe is compressed and the sand control hole becomes smaller. S45, production continues after the size of the sand-proof hole is restored to its initial value.

[0014] The following are further optimizations and / or improvements to the second technical solution of the above invention: In step S4 above, setting the packer specifically involves: lifting the pipe string a certain distance, rotating the pipe string forward a certain number of times, lowering the pipe string again, applying a downward pressure less than the design shear force of the shear pin, and then setting the packer.

[0015] In steps S41 to S45 above, the packer is always in the set-sealing state.

[0016] This invention features a rational and compact structure. The through-holes on the outer side of the base pipe are staggered, ensuring both the strength of the base pipe and serving as a formation fluid channel, facilitating the cleaning of the screen pipe. The supporting cylinder and the suspension joint are connected by shear pins. The shear pins have a designed shearing force. The shear pin strength allows for the suspension of a packer and a certain number of tubing pipes at the lower end of the suspension joint. A downward pressure is applied to the upper joint through the tubing string. This downward pressure exceeds the shear pin's designed shearing force, causing it to shear the pin. After the shear pin breaks, when the upper joint is lifted or lowered, the upper joint, connected to the base pipe, drives the suspension joint to reciprocate up and down within the supporting cylinder. This relative up-and-down reciprocating motion of the suspension joint changes the size of the sand-proof holes in the screen pipe. Lifting the upper joint increases the size of the sand-proof holes, which helps to remove formation sand clogging the fluid inlet channel during well washing. Attached Figure Description

[0017] Appendix Figure 1 These are schematic diagrams of the main cross-sectional structure of embodiments one to eight of the present invention.

[0018] Appendix Figure 2 This is a schematic diagram of the main structure of the screen tube in Embodiments 1 to 8 of the present invention.

[0019] Appendix Figure 3 For the appendix Figure 2 A magnified structural diagram of point A in the middle.

[0020] Appendix Figure 4 This is a schematic diagram of the main structure of the base tube in Embodiments 1 to 8 of the present invention.

[0021] Appendix Figure 5 For the appendix Figure 4 A magnified structural diagram at point B in the middle.

[0022] Appendix Figure 6 This is a schematic diagram of the main structure of the supporting skeleton in embodiments three to eight of the present invention.

[0023] Appendix Figure 7 These are schematic diagrams of the main cross-sectional structure of embodiments nine and ten of the present invention.

[0024] The codes in the attached diagram are as follows: 1 is the upper connector, 2 is the base pipe, 3 is the suspension connector, 4 is the through hole, 5 is the bearing cylinder, 6 is the shear pin, 7 is the screen pipe, 8 is the sandproof hole, 9 is the lower locking sleeve, 10 is the upper locking sleeve, 11 is the support frame, 12 is the connecting screw, 13 is the first sealing ring, 14 is the second sealing ring, 15 is the limiting step, 16 is the retaining ring, 17 is the lower connector, 18 is the packer, 19 is the pipe string, 20 is the oil pipe, and 21 is the blind plug. Detailed Implementation

[0025] The present invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of the present invention.

[0026] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0027] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figures 1 to 5 As shown, the sand control pipe column includes an upper connector 1, a base pipe 2, and a suspension connector 3, which are fixedly installed together from top to bottom. The base pipe 2 has several through holes 4 that are intersected on the outside. The suspension connector 3 is fitted with a bearing cylinder 5. The upper outer side of the bearing cylinder 5 has several radially through external mounting holes evenly distributed along the circumference. The upper outer side of the suspension connector 3 corresponding to each external mounting hole position is provided with an outward-facing internal mounting hole. Each external mounting hole is provided with a shear pin 6 whose end is installed in the corresponding internal mounting hole. The base pipe 2 is fitted with a screen pipe 7. The screen pipe 7 has strip-shaped sand control holes 8 that are interconnected on the outside. The upper end of the bearing cylinder 5 is provided with a lower locking sleeve 9 fitted on the outside of the suspension connector 3. The upper end of the base pipe 2 is provided with an upper locking sleeve 10 screwed to the lower outer side of the upper connector 1. When the upper locking sleeve 10 is tightened, it presses the upper end of the screen pipe 7 and makes the sand control holes 8 smaller. When the upper locking sleeve 10 is loosened, the screen pipe 7 and the sand control holes 8 can be reset.

[0028] According to the requirements, the lower end face of the upper locking sleeve 10 is tightly fitted with the upper end face of the screen tube 7 to form a metal surface seal. The upper end face of the lower locking sleeve 9 is fixedly connected to the lower end of the screen tube 7 by welding. The lower end face of the lower locking sleeve 9 is tightly fitted with the upper end face of the bearing cylinder 5 to form a metal surface seal. The base tube 2 and the upper connector 1 are fixedly installed together by threads. The upper end of the suspension connector 3 is fixedly installed together with the base tube 2 by threads. The lower end of the suspension connector 3 has two O-rings.

[0029] The through holes 4 on the outer side of the base pipe 2 are staggered, which ensures the strength of the base pipe 2 and also serves as a formation fluid channel, facilitating the cleaning of the screen pipe 7. The supporting cylinder 5 and the suspension joint 3 are suspended by shear pins 6. The shear pins 6 have a designed shearing force. The strength of the shear pins 6 can suspend the packer and a certain number of tubing at the lower end of the suspension joint 3, applying downward pressure to the upper joint 1 through the tubing string. This downward pressure exceeds the designed shearing force of the shear pins 6 and can shear the pins. After the shear pins 6 shear, when the upper joint 1 is lifted and lowered, the upper joint 1, connected to the base pipe 2, drives the suspension joint 3 to move up and down relative to each other within the supporting cylinder 5. The relative up and down reciprocating movement of the suspension joint 3 changes the size of the sand-proof holes 8 of the screen pipe 7. When the upper joint 1 is lifted, the size of the sand-proof holes 8 becomes larger, which helps to remove formation sand blocking the fluid inlet channel during well washing.

[0030] During use, a mechanical packer can be installed at the lower end of the bearing cylinder 5. The upper end of the base pipe 2 is equipped with an upper locking sleeve 10 screwed to the lower outer side of the upper connector 1. Before the sand control tubing is inserted into the well, rotating the upper locking sleeve 10 causes it to move downwards and press against the upper end of the screen pipe 7. After the screen pipe 7 is compressed, the sand control holes 8 become smaller. The size of the sand control holes 8 can be adjusted according to the sand production characteristics of the formation to achieve precise sand control in a single well. One type of screen pipe 7 can meet the sand control needs of sand-producing wells in different areas. After the sand control tubing is lowered to the expected position, the mechanical packer is set and the well is put into production. During the production process, if sand blockage occurs, pressure can be applied to the upper connector 1 to cut the shear pin 6, thus protecting the screen pipe. After the lower end of screen 7 is unconstrained and resets, the size of the sand-proof hole 8 is reset and enlarged. Then, well-washing fluid is injected into the upper connector 1 to remove the formation sand in the sand-proof hole 8 from the inside out. Then, pressure is applied to the upper connector 1 through the set mechanical packer. The lower mechanical packer, the downward-moving upper connector 1, and the upper locking sleeve 10 come closer to each other again and press the upper end of the screen pipe 7, thereby adjusting the size of the sand-proof hole 8 back to the size when it was first inserted into the well. In this way, the sand-blocking accuracy of the sand-proof tubing string is repeatedly and multiple times adjusted, which solves the problems of traditional screen pipe 7 being unable to be cleared after being blocked, short sand-proofing effectiveness, and screen pipe 7 having general sand-blocking accuracy and weak sand-proofing specificity.

[0031] The above-mentioned sand control pipe string can be further optimized and / or improved according to actual needs: Example 2: As an optimization of the above examples, as shown in the appendix. Figure 1 , 2 As shown in Figure 3, the screen tube 7 is a cylindrical helical compression spring with a trapezoidal cross section, and sand-proof holes 8 are formed between every two adjacent turns of the compression spring.

[0032] According to requirements, screen tube 7 is a spring-type screen tube, and the spring is a high-strength cylindrical helical compression spring with a trapezoidal cross-section. The cross-section of the spring is an isosceles trapezoid that is narrower on the inside and wider on the outside. Screen tube 7 is made of high-strength alloy steel with a trapezoidal cross-section. Rotating the upper locking sleeve 10 can adjust the pitch of the high-strength trapezoidal spring, thereby changing the gap between the spring coils. The gap between the spring coils is the sand-proof hole 8, which is a formation fluid channel. The cross-section of the sand-proof hole 8 is a trapezoid that is narrower on the outside and wider on the inside, which can prevent formation sand from clogging the sand-proof hole 8.

[0033] Example 3: As an optimization of the above examples, as shown in the appendix. Figures 1 to 6 As shown, the inner side of the sieve tube 7 is provided with a support frame 11 that is fitted onto the outer side of the base tube 2. The support frame 11 is a cylindrical shape with a hollow center. The upper outer side and the lower outer side of the support frame 11 are each evenly distributed with several connecting screws 12 whose ends are fixed to the outer side of the base tube 2 along the circumference.

[0034] During use, the upper and lower outer sides of the support frame 11 are each evenly distributed with several connecting screws 12, the ends of which are fixed to the outer side of the base pipe 2. This allows the support frame 11 and the base pipe 2 to be stably installed together. The outer side of the support frame 11 can be made to fit against the inner wall of the screen pipe 7 as needed, thus providing support and alignment for the screen pipe 7. The powerful trapezoidal spring can slide linearly up and down along the outer wall of the support frame 11 under compression and tension. Before the sand control tubing is inserted into the well, the sand-blocking accuracy of the screen pipe 7 is adjusted according to the sand production characteristics of the sand control well formation. Rotating the upper locking sleeve 10 clockwise narrows the sand-blocking hole 8 of the screen pipe 7 (reducing the spring pitch) and decreases the sand-blocking accuracy. Rotating the upper locking sleeve 10 counterclockwise widens the sand-blocking hole 8 of the screen pipe 7 (increasing the spring pitch) and increases the sand-blocking accuracy. During the adjustment of the sand-blocking accuracy, the upper locking sleeve 10 and the lower locking sleeve 9 are tightly fitted to the end face of the screen pipe 7 to maintain a seal.

[0035] Example 4: As an optimization of the above examples, as shown in the appendix. Figures 1 to 5 As shown, the surface of the screen tube 7 is provided with an anti-corrosion layer.

[0036] According to requirements, the surfaces of the upper connector 1, the base pipe 2, the suspension connector 3, the upper locking sleeve 10, the lower locking sleeve 9, the bearing cylinder 5, and the support frame 11 are all equipped with anti-corrosion layers. The anti-corrosion layer is a nickel-phosphorus alloy coating, which can effectively prevent gas corrosion during carbon dioxide injection mining, improve the anti-carbon dioxide gas corrosion resistance of the sand control pipe string, and extend the service life of the sand control pipe string.

[0037] Example 5: As an optimization of the above examples, as shown in the appendix. Figure 1As shown, the lower end of the upper locking sleeve 10 is in sealed contact with the upper end of the screen tube 7, the upper end of the lower locking sleeve 9 is fixedly installed together with the lower end of the screen tube 7, the lower end of the lower locking sleeve 9 is in sealed contact with the upper end of the bearing cylinder 5, and a first sealing ring 13 is provided between the inner side of the lower end of the lower locking sleeve 9 and the outer side of the upper part of the suspension joint 3.

[0038] As required, the first sealing ring 13 is a known O-ring, and two O-rings are installed on the inner side of the lower end of the lower locking sleeve 9 to form a seal with the outer side of the base pipe 2. During use, this design prevents formation sand from flowing into the inner side of the screen pipe 7 and affecting production.

[0039] Example 6: As an optimization of the above examples, as shown in the appendix Figure 1 As shown, a second sealing ring 14 is provided between the inner side of the external mounting hole and the outer side of the shear pin 6.

[0040] As required, the second sealing ring 14 is a known O-ring. During use, this design prevents formation sand from flowing into the space between the bearing cylinder 5 and the suspension joint 3 through the external mounting hole, thus avoiding damage caused by relative movement between the bearing cylinder 5 and the suspension joint 3.

[0041] Example 7: As an optimization of the above examples, as shown in the appendix. Figure 1 As shown, a limiting step 15 is provided on the inner side of the bearing cylinder 5 corresponding to the position below the shear nail 6, and a retaining ring 16 fitted inside the bearing cylinder 5 is screwed to the outer side of the lower end of the suspension joint 3. A lower joint 17 is fixedly installed on the lower end of the bearing cylinder 5 corresponding to the position below the retaining ring 16.

[0042] As required, both the lower connector 17 and the retaining ring 16 are provided with an anti-corrosion layer, which is a nickel-phosphorus alloy coating. This further enhances the sand control string's resistance to carbon dioxide gas corrosion and extends its service life. By setting the retaining ring 16 and the limiting step 15, after the shear pin 6 is sheared, the retaining ring 16 moves upward relative to the bearing cylinder 5 under the drive of the suspension connector 3 and then abuts against the limiting step 15. This prevents the sealing ring from falling off and causing seal failure due to excessive relative movement of the retaining ring 16.

[0043] Example 8: As an optimization of the above examples, as shown in the appendix Figures 1 to 7 As shown, a packer 18 is fixedly installed at the lower end of the lower connector 17.

[0044] According to the requirements, the packer 18 is the existing known Y221 packer. The downward pressure of the packer 18 during setting is less than the sum of the design shearing forces of all the shear pins 6. The lower connector 17 is fixedly installed with the packer 18 by threads. Two oil pipes 20 can be installed from top to bottom at the lower end of the packer 18. A blind plug 21 is fixedly installed at the lower end of the lowest oil pipe 20. The packer 18 can be set to prevent sand from entering production after setting, and it is also convenient to apply downward pressure to the upper connector 1 to shear the shear pins 6, thereby cleaning the screen tube 7 and repeatedly adjusting the width of the sand prevention hole 8.

[0045] Example 9: As attached Figure 1 , 2 As shown, the method of using this sand control pipe column includes the following steps: S1. Assemble the sand control pipe string, tighten the upper locking sleeve 10 according to the sand discharge characteristics of the formation, and adjust the size of the sand control hole 8. S2, connect the upper connector 1 to the pipe string 19, and install the packer 18 at the lower end of the bearing cylinder 5; S3, lower the sand control tubing string into the target position inside the well; S4, set the packer 18, and then start production. If the liquid production rate does not decrease during the production cycle, continue production; if the liquid production rate decreases or production stops during the production cycle, proceed with the following steps: S41, by applying downward pressure to the sand control string at the wellhead through the workover equipment, the shear pin 6 is cut off, the bearing cylinder 5 moves downward relative to the suspension joint 3, and the sand control hole 8 becomes larger; S42, lift the tube string 19 to a certain distance; S43, a certain volume of workover fluid is pumped into the upper end of the tubing string 19 through a pumping device at the wellhead; S44, after the formation sand stuck in the sand control hole 8 is flushed and carried to the wellhead by the workover fluid, the workover equipment is used to lower the pipe string 19, the bearing cylinder 5 moves upward relative to the suspension joint 3, and the screen pipe 7 is compressed and the sand control hole 8 becomes smaller. S45, production will continue after the size of the sand-proof hole 8 is restored to its initial value.

[0046] In heavy oil regions, the mixture of heavy oil and formation sand easily forms an oil-sand encapsulation phenomenon. This oil-sand encapsulation can clog the sand-control holes 8 of the screen pipe 7, leading to a decrease in production. By lowering the tubing string 19 at the wellhead and cutting the shear pins 6 (the shear pins 6 can be identified by the surface weight indicator), the screen pipe 7 is placed in a free state. Raising the sand-control tubing string and moving the upper locking sleeve 10 upwards resets the screen pipe 7, enlarging (widening) the sand-control holes 8 and increasing the sand-control precision. The sand-control holes 8 at the locations of formation sand blockage on the screen pipe 7 become larger (wider). Circulating well workover fluid pumped from the surface can remove the formation sand blocking the sand-control holes 8 of the screen pipe 7, thus restoring the production channel. After lowering the tubing string under wellhead control to restore the original sand-control precision of the screen pipe 7, production can resume. If sand blockage recurs during production, the sand-control precision of the screen pipe 7 can be repeatedly adjusted to restore production. This invention can optimize and adjust the sand-control precision of the screen pipe 7 according to the effective period of sand control, delaying formation sand blockage and extending the effective period of sand control.

[0047] The above-mentioned method of using sand control pipe columns can be further optimized and / or improved according to actual needs: Example 10: As an optimization of the above embodiments, as shown in the appendix Figures 1 to 7 As shown, in step S4, the setting of the packer 18 is specifically as follows: after lifting the pipe string 19 a certain distance, rotating the pipe string 19 clockwise a certain number of times, lowering the pipe string 19 again and applying a downward pressure less than the design shear force of the shear pin 6 to the pipe string 19, the packer 18 is set.

[0048] During steps S41 to S45, the packer 18 remains in the set-sealing state.

[0049] After lifting the pipe string 19 a certain distance, rotate the pipe string 19 clockwise a certain number of times, lower the pipe string 19 again, and apply a downward pressure to the pipe string 19 that is less than the design shearing force of the shear pin 6, and then set the packer 18. This can avoid the packer 18 being unsealed after the shear pin 6 is cut and the pipe string 19 is lifted, ensuring the adjustment of the width of the sand prevention hole 8 on the screen pipe 7. In steps S41 to S45, the packer 18 is always in the set state. In this way, after the shear pin 6 is cut, when the sand prevention pipe string 19 is lifted and lowered, the packer 18 is always in the set state, which facilitates the adjustment of the width of the sand prevention hole 8 on the screen pipe 7.

[0050] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

[0051] The usage process of the preferred embodiment of the present invention: The following describes the process of mechanical sand control operation on a 5.5-inch casing with a sand control string.

[0052] The outer diameter of the screen tube 7 is 104mm, and the sand-blocking accuracy is adjustable from 0.1 to 2mm, that is, the width of the sand-blocking hole 8 is adjustable from 0.1 to 2mm, which can meet the sand-blocking accuracy requirements of different areas. The outer diameter of the base tube 2 is 73mm and the inner diameter is 55.75mm. The diameter of the through hole 4 of the base tube 2 is 8mm, and the channel is unobstructed after the formation fluid enters the base tube 2. All shear pins 6 are designed to have a shearing force of 120kN, which meets the requirements of pressurized setting and suspension of the Y221 packer 18.

[0053] Before the tool is lowered into the well, adjust the sand-blocking accuracy (width of sand-proof hole 8) of the upper locking sleeve 10 clockwise to match the sand-producing characteristics of the formation in the sand-proof well. After the sand-blocking accuracy is adjusted, connect it to the tubing string 19. Lower the sand-proof tubing string to the expected position. After lifting the tubing string 19 a certain distance, rotate the tubing string 19 clockwise a certain number of turns and lower the tubing string 19. Apply a downward pressure of 50 to 60 kN to set the Y221 packer 18. The downward pressure to set the Y221 packer 18 must not exceed the design shearing force of the shear pin 6. After the packer 18 is set, sand-proof production is put into operation.

[0054] If the production volume decreases or production stops due to formation sand production during the production cycle, a downforce of 120 to 140 kN is applied to the tubing string 19 at the wellhead using workover equipment. This downforce is made greater than the design shearing force of the shear pin 6 to shear the shear pin 6. The shear pin 6 being sheared can be judged by the surface weight display. The tubing string 19 is then raised to a certain distance (the retaining ring 16 moves up until it contacts the limiting step 15). The width of the sand control hole 8 of the screen pipe 7 increases. A certain volume of workover fluid is pumped into the wellhead using a pumping device. The formation sand stuck in the sand control hole 8 and the fluid inlet channel is carried to the wellhead by the workover fluid. After cleaning, the sand control tubing string is lowered a certain distance again using workover equipment. The screen pipe 7 is compressed until it returns to its initial sand control accuracy before production continues.

Claims

1. A sand control string, characterized in that The device comprises an upper joint, a base pipe and a hanging joint fixed and installed in sequence from top to bottom, staggered distribution of a plurality of through holes on the outer side of the base pipe, a bearing cylinder is sleeved on the outer side of the hanging joint, a plurality of radial through holes are uniformly distributed on the outer side of the upper part of the bearing cylinder, an inner mounting hole is arranged on the outer side of the upper part of the hanging joint corresponding to each outer mounting hole, a shear pin is arranged in each outer mounting hole, a screen pipe is sleeved on the outer side of the base pipe, a strip-shaped sand prevention hole is arranged on the outer side of the screen pipe, a lower locking sleeve is arranged on the upper end of the bearing cylinder, an upper locking sleeve is arranged on the upper end of the base pipe, the upper locking sleeve is tightened to press the upper end of the screen pipe and make the sand prevention hole smaller, and the screen pipe and the sand prevention hole can be reset when the upper locking sleeve is loosened.

2. The sand control string of claim 1, wherein The screen pipe is a trapezoidal cross-section cylindrical compression spring, and the compression spring forms a sand prevention hole between each adjacent two turns.

3. The sand control string of claim 2, wherein A support framework is arranged on the inner side of the screen pipe and sleeved on the outer side of the base pipe, the support framework is in the shape of a hollow cylinder with the middle part, a plurality of connecting screws are uniformly distributed on the outer side of the upper part and the lower part of the support framework and fixedly installed on the outer side of the base pipe; or / and, a corrosion-resistant layer is arranged on the surface of the screen pipe.

4. The sand control string of claim 1 or 2 or 3, wherein The lower end of the upper locking sleeve is in sealing contact with the upper end of the screen pipe, the upper end of the lower locking sleeve is fixedly installed with the lower end of the screen pipe, the lower end of the lower locking sleeve is in sealing contact with the upper end of the bearing cylinder, and a first sealing ring is arranged between the inner side of the lower end of the lower locking sleeve and the outer side of the upper part of the hanging joint; or / and, a second sealing ring is arranged between the inner side of the outer mounting hole and the outer side of the shear pin.

5. The sand control string of claims 1 or 2 or 3, wherein A limiting step is arranged on the inner side of the bearing cylinder corresponding to the position below the shear pin, a stop ring is screwed on the outer side of the lower end of the hanging joint and sleeved on the inner side of the bearing cylinder, and a lower joint is fixedly installed on the lower end of the bearing cylinder corresponding to the position below the stop ring.

6. The sand control string of claim 4, and wherein A limiting step is arranged on the inner side of the bearing cylinder corresponding to the position below the shear pin, a stop ring is screwed on the outer side of the lower end of the hanging joint and sleeved on the inner side of the bearing cylinder, and a lower joint is fixedly installed on the lower end of the bearing cylinder corresponding to the position below the stop ring.

7. The sand control string of claim 5, wherein A packer is fixedly installed on the lower end of the lower joint.

8. The sand control string of claim 6, wherein A packer is fixedly installed on the lower end of the lower joint.

9. A method of using a sand control string according to any one of claims 1 to 8, characterized in that The steps are as follows: S1, assemble the sand prevention pipe column, tighten the upper locking sleeve according to the sand production characteristics of the stratum, and adjust the size of the sand prevention hole; S2, connect the upper joint with the pipe string, and install the packer on the lower end of the bearing cylinder; S3, lower the sand prevention pipe column into the well to the target position; S4, set the packer, then start production, if the liquid production does not decrease during the production period, continue production; if the liquid production decreases or stops during the production period, the following steps are performed: S41, apply downward pressure to the sand prevention pipe column at the wellhead through the workover equipment, shear the shear pin, move the bearing cylinder downward relative to the hanging joint, and enlarge the sand prevention hole; S42, lift the pipe string to a certain distance; S43, pump a certain volume of workover fluid into the upper end of the pipe string at the wellhead through the pump injection equipment; S44, after the stratum sand blocked in the sand prevention hole is flushed and carried to the wellhead by the workover fluid, lower the pipe string by using the workover equipment, move the bearing cylinder upward relative to the hanging joint, compress the screen pipe, and make the sand prevention hole smaller; S45, continue production after the size of the sand prevention hole returns to the initial value.

10. The method of using a sand control string as defined in claim 9, wherein In step S4, the setting packer is set as follows: after the pipe string is lifted by a certain distance, the pipe string is rotated by a certain number of turns, the pipe string is lowered again and a downward pressure smaller than the designed shearing force of the shear pin is applied to the pipe string to set the packer; or / and, in steps S41 to S45, the packer is always in a setting state.

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