Gravel packing tool and using method

Abstract

The invention relates to the technical field of sand control well completion in oil exploitation, in particular to a gravel packing tool and a using method. According to the technical scheme, the device comprises a releasing mechanism, an anchoring mechanism, an oil sleeve annulus sealing mechanism and a filling conversion mechanism, the lower end of an anchor body of the anchoring mechanism is connected with an upper center pipe, a liner pipe is arranged on the inner side of the anchor body, multiple sets of pressing plates and anchor tile grooves are arranged on the outer wall of the anchor body, and springs are arranged between anchor tiles and the pressing plates; a cylinder sleeve and a distance ring are arranged on the outer side of the upper center pipe, a locking ring is arranged at the lower end of the anchor body, an adjusting ring, a leather cup pressing cap and a leather cup are installed on the outer wall of the outer center pipe, and the outer side of the leather cup pressing cap is connected with the lower end of the cylinder sleeve through a second shear pin. The tubular column has the beneficial effects that various working conditions such as safe well descending, tubular column anchoring, annulus high-pressure sealing, filling and inverse well flushing are converted through one tubular column, two releasing modes of mechanical releasing and hydraulic releasing are achieved, the structure is simple, the number of solid parts is relatively small, the machining amount is small, and the cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of sand control completion in oil exploitation, and particularly relates to a gravel packing tool and a using method thereof. Background Art

[0002] For sandstone reservoirs, during the exploitation of oil and gas wells, sand production often causes low production or shutdown of the oil and gas wells. Therefore, before the production of such oil and gas wells, sand control completion is required. Gravel packing sand control has become the leading process technology in a series of sand control process technologies due to its long effective period, high seepage capacity, etc. The gravel packing tool is the key tool to realize the gravel packing sand control process. At present, in the application process of conventional gravel packing tools, the following deficiencies still exist: (1) Conventional gravel packing tools use a piston to set the packer rubber to achieve the sealing of the annulus between the oil casing; the piston sets the anchor slips to achieve the high-pressure anchoring of the pipe string; and the combined filling conversion tool has multiple flow channels to achieve formation filling, circulating filling, and reverse circulation washing and sand flushing. As a result, the tool structure is complex, the cost is relatively high, and under the limited wellbore size, the size of the sand addition channel is limited, making it difficult to meet the requirements of high-displacement and high-sand ratio formation filling and sand control. (2) Conventional gravel packing tools all adopt the mechanical releasing method of rotating and reverse buckling. The main reason is that if hydraulic releasing is adopted, during the filling and sand control squeezing construction process, premature releasing may occur due to the fluctuation or abnormality of the squeezing pressure, resulting in the failure of the sealing fit between the inner and outer pipe strings of the filling and sand control, and the squeezing mortar entering the sandwich between the inner and outer pipe strings of the sand control, causing sand sticking during the subsequent removal of the inner pipe string of the sand control, bringing about major repair operations for the oil well. However, this mechanical releasing method brings difficulties in releasing for the filling and sand control operations of complex wells such as medium-deep wells, large-angle wells, and horizontal wells. (3) The remaining well components of conventional gravel packing tools include mechanisms such as slip anchoring and rubber barrel sealing. For the mechanical hard-locking slip anchoring mechanism, during the later maintenance and removal of the sand control pipe string by pulling the filter, it often gets stuck and blocked, increasing the risk of major repair operations and the operation cost.

[0003] To solve the above problems, a gravel packing tool and a using method thereof are proposed, which have a simple structure, fewer remaining well components, and an integration of mechanical and hydraulic releasing. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned defects existing in the prior art, and provide a gravel packing tool and a using method thereof, which can realize the conversion of multiple working conditions such as safe well entry, pipe string anchoring, annulus high-pressure sealing, filling, and reverse well washing with one trip of the pipe string, and achieve two releasing methods of mechanical and hydraulic releasing. The whole set of tools has a simple structure, relatively few physical components, small processing volume, and low cost.

[0005] A gravel packing tool mentioned in the present invention has the following technical solution: It includes a releasing mechanism, and also includes an anchoring mechanism, an oil-casing annulus sealing mechanism, and a filling conversion mechanism. The anchoring mechanism includes an anchor body, a pressure plate, anchor tiles, springs, and a liner. The lower end of the anchor body is connected to the upper central pipe. A liner is provided inside the anchor body. Multiple groups of pressure plates and anchor tile grooves are provided on the outer wall of the anchor body. The anchor tiles are installed in the anchor tile grooves, and springs are provided between the anchor tiles and the pressure plates. During the gravel packing process, it is anchored to the inner wall of the casing through the cooperation of the anchor tiles and the pressure plates. The oil-casing annulus sealing mechanism includes a locking ring, a cylinder sleeve, a spacer ring, an outer central pipe, an adjusting ring, a cup packing cap, a second shear pin, and a cup packing. A cylinder sleeve and a spacer ring are provided outside the upper central pipe. A locking ring is provided at the lower end of the anchor body. An adjusting ring, a cup packing cap, and a cup packing are installed on the outer wall of the outer central pipe. The adjusting ring is provided above the cup packing cap, and the cup packing is provided below it. The outer side of the cup packing cap is connected to the lower end of the cylinder sleeve through the second shear pin. The filling conversion mechanism includes an inner filling pipe, an outer filling sleeve, a flow splitting sleeve, a closing sleeve, and a closing spring. Inner filling holes are provided on the outer wall of the inner filling pipe. A flow splitting sleeve is installed on the outer wall of the inner filling pipe. An outer filling sleeve is provided outside the flow splitting sleeve. Outer filling holes are provided on the outer filling sleeve. The lower end of the outer filling sleeve is connected to a lower joint. A closing spring is installed in the inner cavity of the lower joint. The upper part of the closing spring is connected to the closing sleeve, and the closing sleeve is located between the inner filling pipe and the flow splitting sleeve. By squeezing the closing spring at the lower end of the inner filling pipe, the closing sleeve is located below the inner filling holes and the outer filling holes, and the inner filling holes and the outer filling holes form a connected filling channel.

[0006] Preferably, the above-mentioned releasing mechanism includes a releasing joint, a locking block seat, a releasing steel ball, a releasing ball seat, a locking block, a releasing shear pin, an inner central pipe, and a connecting sleeve. A releasing ball seat is provided in the inner cavity of the inner central pipe for supporting the releasing steel ball. A groove is provided on the upper outer side of the releasing ball seat. The outer wall of the inner central pipe is connected to the locking block seat through the releasing shear pin. A locking block is installed on the locking block seat. The releasing joint is installed on the outer side of the locking block seat. The lower end of the releasing joint is connected to the connecting sleeve. The lower end of the connecting sleeve is connected to the outer central pipe.

[0007] Preferably, the above-mentioned oil-casing annulus sealing mechanism further includes a setting ball, a first shear pin, and a ball seat. The ball seat is connected to the inner wall of the upper part of the inner filling pipe through the first shear pin, and the ball seat is used for supporting the setting ball.

[0008] Preferably, the above-mentioned filling conversion mechanism further includes a baffle plate, an inner lower joint, and a circulating ball. A baffle plate and an inner lower joint are provided at the lower part of the inner filling pipe. A circulating ball is provided inside the inner lower joint; after the first shear pin of the ball seat is cut off, the position of the ball seat is restricted by the baffle plate.

[0009] Preferably, a limiting protrusion is provided at the top of the inner wall of the above-mentioned flow splitting sleeve. When the closing sleeve returns to its position, its upper end contacts and cooperates with the limiting protrusion.

[0010] Preferably, both ends of the above-mentioned pressing plate are fixed on the outer wall of the anchor body through bolts. Two groups of semi-circular fixing teeth are provided at the outer end of the anchor tile. The center of the anchor tile contacts the pressing plate through a spring, and the inner end of the anchor tile contacts the outer wall of the liner to achieve positioning.

[0011] Preferably, a lock catch is provided at the top of the above-mentioned cylinder liner, and is connected with a lock ring through the lock catch. A limiting inner protrusion is provided at the lower part of the lock catch, and the limiting inner protrusion cooperates with the bottom end of the anchor body to achieve positioning; the lower inner wall of the cylinder liner and the leather cup pressing cap are connected through a second shear pin, and the shear resistance of the second shear pin is less than that of the first shear pin; the middle part of the cylinder liner is supported by a spacer ring.

[0012] Preferably, a pressure transmission hole is provided between the above-mentioned upper central pipe and the cylinder liner, a first communication hole is provided at the lower side of the cylinder liner, and a second communication hole is provided on the outer central pipe above the adjusting ring.

[0013] The usage method of the gravel packing tool mentioned in the present invention includes the following processes: (1) Safe lowering: Lower the gravel packing tool into the casing through the tubing. Since the gravel packing tool has a two-way flow performance from inside to outside, the internal and external pressures are kept consistent during the lowering process of the gravel packing tool. Therefore, it will not be set and anchored, and safe lowering can be achieved. At the same time, the leather cup is pre-pressed in the cylinder liner to ensure that the leather cup is not scratched or worn during the lowering process; (2) Leather cup release and annulus sealing: Drop a setting ball from the tubing at the surface wellhead. Then, pressurize from the surface wellhead until the second shear pin is cut off. The cylinder liner moves upward under hydraulic pressure and is fixed on the lock ring. The leather cup is exposed and seals the annulus between it and the casing; (3) Filling channel opening: Continue to pressurize from the tubing until the first shear pin is cut off. The setting ball and the ball seat are pressed and move downward together to the baffle at the lower part of the filling channel, and the internal and external of the gravel packing tool are connected through the filling channel; (4) Formation filling and sand control: Close the casing gate valve. Inject the sand-carrying fluid and proppant from the tubing at the surface wellhead. The sand-carrying fluid and proppant pass through the inside of the gravel packing tool, flow through the filling channel and enter the annulus between the gravel packing tool and the casing, and continue to descend into the formation to achieve formation filling and sand control; at the same time, the anchoring mechanism of the gravel packing tool is under internal pressure, and the anchor tile is pressed to open and anchor on the inner wall of the casing; (5) Circulating filling sand control: Open the casing gate valve, inject the sand-carrying fluid and proppant into the tubing from the surface wellhead, pass through the interior of the gravel packing tool, flow through the filling channel into the annulus between the gravel packing tool and the casing, continue to descend, enter the annulus between the screen pipe connected to the lower part of the gravel packing tool and the casing. The proppant remains between the screen pipe and the casing. The sand-carrying fluid passes through the screen pipe, is filtered, and then flows into the annulus between the inner filling pipe and the lower joint through the inner lower joint. Then it continues to rise along the annulus between the inner filling pipe and the outer central pipe, and then enters the annulus between the cylinder sleeve and the casing through the second communication hole of the outer central pipe and the first communication hole of the cylinder sleeve, and returns to the surface in a reverse circulation, realizing gravel packing sand control in the annulus between the screen pipe and the casing. At the same time, under the internal pressure, the anchoring mechanism of the gravel packing tool causes the anchor shoes to expand under pressure and anchor on the inner wall of the casing; (6) Reverse circulation sand washing: Conduct reverse circulation well flushing and sand washing from the annulus between the tubing and the casing. The liquid flow passes through the cylinder sleeve of the gravel packing tool, goes downward through the first communication hole and the second communication hole, enters the annulus between the inner central pipe and the outer central pipe and continues to descend, then enters the sandwich space between the outer filling sleeve and the diverter sleeve, and then enters the inner lower joint cavity through the third communication hole. The circulating ball is pressed to block the lower flow channel. The liquid flow goes upward through the inside of the inner filling pipe until it passes through the interior of the gravel packing tool and returns to the surface through the inside of the tubing, flushing out the gravel remaining in the tubing and the interior of the gravel packing tool during the circulating filling process in a reverse circulation until it is washed clean.

[0014] Preferably, the method for using the gravel packing tool mentioned in the present invention further includes the following process: (7) Releasing the connection and pulling out the filling inner pipe: Since there is no pressure inside the anchoring mechanism of the gravel packing tool, the anchor shoes retract under the action of the spring, and then hydraulic or mechanical releasing is carried out; ① Hydraulic releasing: Drop the releasing ball. The releasing ball settles to the releasing ball seat under small-displacement pumping or gravity. Pressurize from the inside of the tubing until the releasing shear pin is cut off. The releasing ball seat moves downward and releases the lock block. When the tubing string is lifted, the lower clamping claws of the releasing joint retract, causing the connecting sleeve between the filling inner pipe string and the filling outer pipe string to lose restraint, realizing the release; ② Mechanical releasing: There is no pressure inside the anchoring mechanism of the gravel packing tool. The anchor shoes retract under the action of the spring. Rotate the tubing connected to the upper part of the gravel packing tool clockwise from the surface, driving the anchoring mechanism, the upper central pipe, and the releasing joint to rotate clockwise. Since the screen pipe connected to the lower part of the filling outer pipe string is fixed by the gravel filled in the circulating filling and does not rotate, the reverse thread of the lower part of the releasing joint rotates and disengages to realize the release; (8) Sand control production: After the filling inner pipe string is pulled out, without the extrusion of the inner filling pipe, the closing sleeve moves upward under the action of the closing spring to close the filling channel; the leather cup seals the annulus between the gravel packing tool and the casing. The fluid of the oil and gas layer passes through the gravel layer filled in the lower part of the gravel packing tool and the screen pipe and then rises, realizing sand control production.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In terms of structure, the present invention realizes the design and innovation of a gravel packing tool integrating an anchor shoe + cup packer + filling, and realizes two types of releasing methods, hydraulic and mechanical, on the gravel packing tool. The whole set of tool has a simple structure, relatively few solid parts, small processing amount and low cost; (2) In terms of function, one trip of tubing realizes the integrated and multi-functional requirements such as safe well entry, tubing anchoring, high-pressure annular sealing, conversion of three working conditions of formation filling, annular filling and backwashing, two types of releasing methods, hydraulic and mechanical back-off, and sand control production. Moreover, during the gravel packing process, the tubing does not need to be moved, the construction is safe, efficient and highly reliable, and there is no risk of sand sticking. In addition, after the inner tubing is removed, there are very few remaining parts in the well, and there are no hard-to-release parts such as anchor shoes and slip anchors, making the later maintenance and well repair operations safer and more reliable, and having good adaptability to complex structure wells such as deep wells and horizontal wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the present invention; Figure 2 is a schematic structural diagram during safe well entry; Figure 3 is a schematic structural diagram of cup packer release and annular sealing; Figure 4 is a schematic structural diagram of the filling channel opening; Figure 5 is a schematic structural diagram of formation gravel packing; Figure 6 is a schematic structural diagram of circulating gravel packing; Figure 7 is a schematic structural diagram of reverse circulation well washing and sand flushing; Figure 8 is a schematic structural diagram of dropping a releasing ball; Figure 9 is a schematic structural diagram of hydraulic releasing; Figure 10 is a schematic structural diagram of pulling out the sand control service tubing; Figure 11 is a schematic structural diagram of the remaining sand control tool in the well; In the above figure: anchor body 1, bolt 2, pressing plate 3, anchor tile 4, spring 5, liner 6, upper central tube 7, locking ring 8, cylinder liner 9, spacer ring 10, releasing joint 11, locking block seat 12, releasing steel ball 13, releasing ball seat 14, locking block 15, releasing shear pin 16, inner central tube 17, setting ball 18, first shear pin 19, ball seat 20, inner filling tube 21, baffle plate 22, inner lower joint 23, circulating ball 24, connecting sleeve 25, outer central tube 26, adjusting ring 27, packing cup pressing cap 28, second shear pin 29, packing cup 30, outer filling sleeve 31, flow dividing sleeve 32, closing sleeve 33, closing spring 34, lower joint 35, casing 36, filling channel 37, pressure transmission hole 7.1, locking buckle 9.1, limiting inner projection 9.2, first communication hole 9.3, lower beam claw 11.1, third communication hole 23.1, second communication hole 26.1. Detailed implementation mode

[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0018] Example 1, referring to Figures 1-11 , a gravel packing tool mentioned in the present invention includes a releasing mechanism, and also includes an anchoring mechanism, an oil-casing annulus sealing mechanism, and a packing conversion mechanism. The anchoring mechanism includes an anchor body 1, a pressing plate 3, an anchor tile 4, a spring 5, and a liner 6. The lower end of the anchor body 1 is connected to the upper central tube 7. A liner 6 is provided inside the anchor body 1. Multiple groups of pressing plates 3 and anchor tile grooves are provided on the outer wall of the anchor body 1. The anchor tile 4 is installed in the anchor tile groove, and a spring 5 is provided between the anchor tile 4 and the pressing plate 3. During the gravel packing process, it is anchored to the inner wall of the casing 36 through the cooperation of the anchor tile 4 and the pressing plate 3; The oil-casing annulus sealing mechanism includes a locking ring 8, a cylinder liner 9, a spacer ring 10, an outer central tube 26, an adjusting ring 27, a packing cup pressing cap 28, a second shear pin 29, and a packing cup 30. A cylinder liner 9 and a spacer ring 10 are provided outside the upper central tube 7. A locking ring 8 is provided at the lower end of the anchor body 1. An adjusting ring 27, a packing cup pressing cap 28, and a packing cup 30 are installed on the outer wall of the outer central tube 26. The adjusting ring 27 is provided on the upper side of the packing cup pressing cap 28, and the packing cup 30 is provided on the lower side. The outer side of the packing cup pressing cap 28 is connected to the lower end of the cylinder liner 9 through a second shear pin 29; The filling conversion mechanism includes an inner filling pipe 21, an outer filling sleeve 31, a flow splitting sleeve 32, a closing sleeve 33, and a closing spring 34. The outer wall of the inner filling pipe 21 is provided with inner filling holes. The flow splitting sleeve 32 is installed on the outer wall of the inner filling pipe 21. The outer filling sleeve 31 is provided on the outside of the flow splitting sleeve 32, and the outer filling sleeve 31 is provided with outer filling holes. The lower end of the outer filling sleeve 31 is connected to a lower joint 35. The closing spring 34 is installed in the inner cavity of the lower joint 35. The upper part of the closing spring 34 is connected to the closing sleeve 33, and the closing sleeve 33 is located between the inner filling pipe 21 and the flow splitting sleeve 32. By squeezing the closing spring 34 at the lower end of the inner filling pipe 21, the closing sleeve 33 is located below the inner filling holes and the outer filling holes, and the inner filling holes and the outer filling holes form a connected filling channel 37.

[0019] Preferably, the releasing mechanism includes a releasing joint 11, a locking block seat 12, a releasing steel ball 13, a releasing ball seat 14, a locking block 15, a releasing shear pin 16, an inner central pipe 17, and a connecting sleeve 25. The inner cavity of the inner central pipe 17 is provided with the releasing ball seat 14 for supporting the releasing steel ball 13. The upper part of the outside of the releasing ball seat 14 is provided with a groove. The outer wall of the inner central pipe 17 is connected to the locking block seat 12 through the releasing shear pin 16. The locking block 15 is installed on the locking block seat 12. The releasing joint 11 is installed on the outside of the locking block seat 12. The lower end of the releasing joint 11 is connected to the connecting sleeve 25, and the lower end of the connecting sleeve 25 is connected to the outer central pipe 26.

[0020] Preferably, the oil casing annulus sealing mechanism further includes a setting ball 18, a first shear pin 19, and a ball seat 20. The ball seat 20 for supporting the setting ball 18 is connected to the inner wall of the upper part of the inner filling pipe 21 through the first shear pin 19.

[0021] Preferably, the filling conversion mechanism further includes a baffle 22, an inner lower joint 23, and a circulating ball 24. The lower part of the inner filling pipe 21 is provided with the baffle 22 and the inner lower joint 23, and the circulating ball 24 is provided inside the inner lower joint 23; after the first shear pin 19 of the ball seat 20 is cut off, the position of the ball seat 20 is restricted by the baffle 22.

[0022] Preferably, a limiting protrusion is provided at the top of the inner wall of the flow splitting sleeve 32. When the closing sleeve 33 returns to its position, the upper end contacts and cooperates with the limiting protrusion.

[0023] Preferably, both ends of the pressing plate 3 are fixed to the outer wall of the anchor body 1 through bolts 2. Two groups of semi-circular fixing teeth are provided at the outer end of the anchor tile 4. The center of the anchor tile 4 contacts the pressing plate 3 through a spring 5, and the inner end of the anchor tile 4 contacts the outer wall of the liner 6 to achieve positioning.

[0024] Preferably, a latch 9.1 is provided at the top of the above-mentioned cylinder liner 9, which is connected to the lock ring 8 through the latch 9.1. A limiting inner protrusion 9.2 is provided at the lower part of the latch 9.1, and the limit is realized by the cooperation of the limiting inner protrusion 9.2 and the bottom end of the anchor body 1; the lower inner wall of the cylinder liner 9 is connected to the leather cup pressing cap 28 through a second shear pin 29, and the shear resistance of the second shear pin 29 is less than that of the first shear pin 19; the middle part of the cylinder liner 9 is supported by a spacer ring 10.

[0025] Preferably, a pressure transmission hole 7.1 is provided between the above-mentioned upper central pipe 7 and the cylinder liner 9. A first communication hole 9.3 is provided on the lower side of the cylinder liner 9, and a second communication hole 26.1 is provided on the outer central pipe 26 above the adjusting ring 27.

[0026] The usage method of the gravel packing tool mentioned in the present invention includes the following processes: (I) Safe lowering: The gravel packing tool is lowered into the casing 36 through the tubing. Since the gravel packing tool has a two-way flow performance from inside to outside, the internal and external pressures are kept consistent during the lowering process of the gravel packing tool. Therefore, it will not be set and anchored, and safe lowering is achieved. At the same time, the leather cup 30 is pre-pressed in the cylinder liner 9 to ensure that the leather cup 30 is not scratched or worn during the lowering process; (II) Leather cup release and annulus sealing: A setting ball 18 is dropped into the tubing from the surface wellhead. Then, pressure is applied from the surface wellhead until the second shear pin 29 is cut off. The cylinder liner 9 moves upward under the hydraulic action and is fixed on the lock ring 8. The leather cup 30 is exposed and seals the annulus between it and the casing 36; (III) Filling channel opening: Continue to apply pressure from the tubing until the first shear pin 19 is cut off. The setting ball 18 and the ball seat 20 are pressed and move downward together to the baffle 22 at the lower part of the filling channel 37, and the internal and external connections of the gravel packing tool are realized through the filling channel 37; (IV) Formation filling and sand control: Close the casing gate valve. Inject the sand-carrying fluid and proppant from the tubing at the surface wellhead. The sand-carrying fluid and proppant pass through the inside of the gravel packing tool, flow through the filling channel 37 and enter the annulus between the gravel packing tool and the casing 36, and continue to descend into the formation to achieve formation filling and sand control; at the same time, under the internal pressure, the anchor mechanism of the gravel packing tool causes the anchor tiles 4 to be pressed and opened, and is anchored on the inner wall of the casing 36; (5) Circulating filling sand control: Open the casing gate valve, inject the sand-carrying fluid and proppant into the tubing from the surface wellhead, pass through the interior of the gravel packing tool, flow through the filling channel 37 into the annulus between the gravel packing tool and the casing 36, continue to descend, enter the annulus between the casing 36 and the screen pipe connected to the lower part of the gravel packing tool, the proppant remains between the screen pipe and the casing 36, the sand-carrying fluid passes through the screen pipe and then flows into the annulus between the inner filling pipe 21 and the lower joint 35 through the inner lower joint 23, continues to rise along the annulus between the inner filling pipe 17 and the outer central pipe 26, and then enters the annulus between the cylinder liner 9 and the casing 36 through the second communication hole 26.1 of the outer central pipe 26 and the first communication hole 9.3 of the cylinder liner 9, and returns to the surface in reverse circulation, realizing gravel packing sand control in the annulus between the screen pipe and the casing 36. At the same time, under the internal pressure, the anchor mechanism of the gravel packing tool causes the anchor shoe 4 to expand under pressure and anchor on the inner wall of the casing 36; (6) Reverse circulation sand washing: Conduct reverse circulation well washing and sand washing from the annulus between the tubing and the casing 36. The liquid flow passes through the cylinder liner 9 of the gravel packing tool and descends through the first communication hole 9.3 and the second communication hole 26.1 into the annulus between the inner central pipe 17 and the outer central pipe 26 and continues to descend, the sandwich space between the outer filling sleeve 31 and the diverter sleeve 32, and then enters the inner cavity of the inner lower joint 23 through the third communication hole 23.1. The circulating ball 24 is pressed to block the lower flow channel, and the liquid flow rises through the interior of the inner filling pipe 21 until it passes through the interior of the gravel packing tool and returns to the surface through the tubing in circulation, flushing out the gravel remaining in the tubing and the interior of the gravel packing tool during the circulating filling process to the surface in reverse circulation until it is washed clean.

[0027] Preferably, the method for using the gravel packing tool mentioned in the present invention further includes the following process: (7) Releasing the connection and pulling out the filling inner pipe: Since there is no pressure inside the anchor mechanism of the gravel packing tool, the anchor shoe 4 retracts under the action of the spring 5, and then hydraulic or mechanical releasing is carried out; ① Hydraulic releasing: Drop the releasing ball 13. Under the action of small-displacement pumping or gravity, the releasing ball 13 settles to the releasing ball seat 14, and pressure is applied from the interior of the tubing until the releasing shear pin 16 is cut off. The releasing ball seat 14 descends, releasing the locking block 15; when the tubing string is lifted, the lower clamping claws 11.1 of the releasing joint 11 retract, causing the connecting sleeve 25 between the filling inner pipe string and the filling outer pipe string to lose restraint, realizing the release; ② Mechanical releasing: There is no pressure inside the anchor mechanism of the gravel packing tool, and the anchor shoe 4 retracts under the action of the spring 5. Rotate the tubing connected to the upper part of the gravel packing tool clockwise from the surface, driving the anchor mechanism, the upper central pipe 7 and the releasing joint 11 to rotate clockwise. Since the screen pipe connected to the lower part of the filling outer pipe string is fixed by the gravel filled in the circulating filling and does not rotate, the reverse-threaded part of the lower part of the releasing joint 11 rotates counterclockwise to release the connection and achieve the release; (8) Sand control production: After the inner filling string is retrieved, without the extrusion of the inner filling pipe 21, the closing sleeve 33 moves upward under the action of the closing spring 34 to close the filling channel 37; the cup 30 seals the annulus between the gravel packing tool and the casing 36, and the fluid in the oil and gas layer ascends through the gravel layer filled at the lower part of the gravel packing tool and the screen pipe, realizing sand control production.

[0028] As mentioned above, only some of the preferred embodiments of the present invention are described. Any person skilled in the art may modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, any corresponding simple modifications or equivalent transformations made according to the technical solutions of the present invention fall within the scope of protection required by the present invention.

Claims

1. A gravel packing tool, including a releasing mechanism, characterized in that: It also includes an anchoring mechanism, an oil-casing annulus sealing mechanism, and a filling conversion mechanism. The anchoring mechanism includes an anchor body (1), a pressing plate (3), an anchor tile (4), a spring (5), and a liner (6). The lower end of the anchor body (1) is connected to the upper central pipe (7). A liner (6) is provided inside the anchor body (1). Multiple groups of pressing plates (3) and anchor tile grooves are provided on the outer wall of the anchor body (1). The anchor tile (4) is installed in the anchor tile groove, and a spring (5) is provided between the anchor tile (4) and the pressing plate (3). During the gravel packing process, it is anchored to the inner wall of the casing (36) through the cooperation of the anchor tile (4) and the pressing plate (3). The oil-casing annulus sealing mechanism includes a locking ring (8), a cylinder sleeve (9), a spacer ring (10), an outer central pipe (26), an adjusting ring (27), a cup packing cap (28), a second shear pin (29), and a cup packing (30). A cylinder sleeve (9) and a spacer ring (10) are provided outside the upper central pipe (7). A locking ring (8) is provided at the lower end of the anchor body (1). An adjusting ring (27), a cup packing cap (28), and a cup packing (30) are installed on the outer wall of the outer central pipe (26). The adjusting ring (27) is provided on the upper side of the cup packing cap (28), and the cup packing (30) is provided on the lower side. The outer side of the cup packing cap (28) is connected to the lower end of the cylinder sleeve (9) through the second shear pin (29). The filling conversion mechanism includes an inner filling pipe (21), an outer filling sleeve (31), a diverter sleeve (32), a closing sleeve (33), and a closing spring (34). Inner filling holes are provided on the outer wall of the inner filling pipe (21). A diverter sleeve (32) is installed on the outer wall of the inner filling pipe (21). An outer filling sleeve (31) is provided outside the diverter sleeve (32). Outer filling holes are provided on the outer filling sleeve (31). The lower end of the outer filling sleeve (31) is connected to a lower sub (35). A closing spring (34) is installed in the inner cavity of the lower sub (35). The upper part of the closing spring (34) is connected to the closing sleeve (33), and the closing sleeve (33) is located between the inner filling pipe (21) and the diverter sleeve (32). By squeezing the closing spring (34) with the lower end of the inner filling pipe (21), the closing sleeve (33) is located below the inner filling holes and the outer filling holes, and the inner filling holes and the outer filling holes form a connected filling channel (37).

2. The gravel packing tool according to claim 1, characterized in that: The releasing mechanism includes a releasing sub (11), a lock block seat (12), a releasing steel ball (13), a releasing ball seat (14), a lock block (15), a releasing shear pin (16), an inner central pipe (17), and a connecting sleeve (25). A releasing ball seat (14) is provided in the inner cavity of the inner central pipe (17) for supporting the releasing steel ball (13). A groove is provided on the upper outer side of the releasing ball seat (14). The outer wall of the inner central pipe (17) is connected to the lock block seat (12) through the releasing shear pin (16). A lock block (15) is installed on the lock block seat (12). The releasing sub (11) is installed on the outer side of the lock block seat (12). The lower end of the releasing sub (11) is connected to the connecting sleeve (25). The lower end of the connecting sleeve (25) is connected to the outer central pipe (26).

3. The gravel packing tool according to claim 2, characterized in that: The oil-casing annulus sealing mechanism further includes a setting ball (18), a first shear pin (19), and a ball seat (20). The ball seat (20) is connected to the upper inner wall of the inner filling pipe (21) by the first shear pin (19) and is used to support the setting ball (18).

4. The gravel packing tool according to claim 3, characterized in that: The filling conversion mechanism further includes a baffle (22), an inner lower joint (23), and a circulating ball (24). The lower part of the inner filling pipe (21) is provided with the baffle (22) and the inner lower joint (23), and the circulating ball (24) is arranged inside the inner lower joint (23). After the first shear pin (19) of the ball seat (20) is cut off, the position of the ball seat (20) is restricted by the baffle (22).

5. The gravel packing tool according to claim 4, characterized in that: A limiting protrusion is provided at the top of the inner wall of the flow dividing sleeve (32). When the closing sleeve (33) returns to its position, its upper end contacts and cooperates with the limiting protrusion.

6. The gravel packing tool according to claim 5, characterized in that: Both ends of the pressing plate (3) are fixed to the outer wall of the anchor body (1) by bolts (2). Two groups of semi-circular fixing teeth are provided at the outer end of the anchor tile (4). The center of the anchor tile (4) contacts the pressing plate (3) through a spring (5), and the inner end of the anchor tile (4) contacts the outer wall of the liner (6) to achieve limiting.

7. The gravel packing tool according to claim 6, characterized in that: A lock catch (9.1) is provided at the top of the cylinder sleeve (9). The lock catch (9.1) is connected to the lock ring (8) in a matching manner. A limiting inner protrusion (9.2) is provided at the lower part of the lock catch (9.1), and the position is limited by the cooperation of the limiting inner protrusion (9.2) and the bottom end of the anchor body (1). The lower inner wall of the cylinder sleeve (9) is connected to the leather cup pressing cap (28) by a second shear pin (29), and the shear resistance of the second shear pin (29) is less than that of the first shear pin (19). The middle part of the cylinder sleeve (9) is supported by a spacer ring (10).

8. The gravel packing tool according to claim 7, characterized in that: A pressure transmission hole (7.1) is provided between the upper central pipe (7) and the cylinder sleeve (9). A first communication hole (9.3) is provided on the lower side of the cylinder sleeve (9). A second communication hole (26.1) is provided on the outer central pipe (26) above the adjusting ring (27).

9. The method for using the gravel packing tool according to claim 8, characterized in that: It includes the following processes: (I) Safe lowering: The gravel packing tool is lowered into the casing (36) through the tubing. Since the gravel packing tool has a two-way flow performance from inside to outside, the internal and external pressures are kept consistent during the lowering process of the gravel packing tool. Therefore, it will not be set or anchored, and safe lowering is achieved. At the same time, the leather cup (30) is pre-pressed inside the cylinder sleeve (9) to ensure that the leather cup (30) is not scratched or worn during the lowering process; (II) Leather cup release and annulus sealing: The setting ball (18) is put into the tubing from the surface wellhead. Then, pressure is applied from the surface wellhead until the second shear pin (29) is cut off. The cylinder sleeve (9) moves upward under the hydraulic action and is fixed to the lock ring (8). The leather cup (30) is exposed and seals the annulus between it and the casing (36); (III) Filling channel opening: Pressure is continuously applied from the tubing until the first shear pin (19) is cut off. The setting ball (18) and the ball seat (20) are pressed and move downward together to the baffle (22) at the lower part of the filling channel (37), and the internal and external connections of the gravel packing tool are realized through the filling channel (37); (4) Formation filling sand control: Close the casing gate valve. Inject the sand-carrying fluid and proppant into the tubing from the surface wellhead. The sand-carrying fluid and proppant pass through the inside of the gravel packing tool, flow through the filling channel (37), enter the annulus between the gravel packing tool and the casing (36), continue to descend, enter the formation, and achieve formation filling sand control. At the same time, under the internal pressure, the anchor mechanism of the gravel packing tool causes the anchor shoe (4) to expand under pressure and anchor on the inner wall of the casing (36). (5) Circulating filling sand control: Open the casing gate valve. Inject the sand-carrying fluid and proppant into the tubing from the surface wellhead. Pass through the inside of the gravel packing tool, flow through the filling channel (37), enter the annulus between the gravel packing tool and the casing (36), continue to descend, enter the annulus between the screen pipe connected to the lower part of the gravel packing tool and the casing (36). The proppant remains between the screen pipe and the casing (36). The sand-carrying fluid passes through the screen pipe, filters, and then flows into the annulus between the inner filling pipe (21) and the lower joint (35) through the inner lower joint (23). Continue to flow upward along the annulus between the inner filling pipe (17) and the outer central pipe (26), and then along the second communication hole (26.1) of the outer central pipe (26) and the first communication hole (9.3) of the cylinder liner (9) into the annulus between the cylinder liner (9) and the casing (36), and reverse circulate to the surface to achieve gravel filling sand control in the annulus between the screen pipe and the casing (36). At the same time, under the internal pressure, the anchor mechanism of the gravel packing tool causes the anchor shoe (4) to expand under pressure and anchor on the inner wall of the casing (36). (6) Reverse circulation sand washing: Conduct reverse circulation well washing and sand washing from the annulus between the tubing and the casing (36). The liquid flow passes through the cylinder liner (9) of the gravel packing tool and descends downward through the first communication hole (9.3) and the second communication hole (26.1) into the annulus between the inner central pipe (17) and the outer central pipe (26), continues to descend, enters the sandwich space between the outer filling sleeve (31) and the diverter sleeve (32), and then passes through the third communication hole (23.1) into the inner cavity of the inner lower joint (23). The circulating ball (24) is pressed to block the lower flow channel. The liquid flow passes upward through the inside of the inner filling pipe (21) until it passes through the inner cavity of the gravel packing tool and returns to the surface through the inside of the tubing, flushing out the gravel remaining inside the tubing and the gravel packing tool during the circulating filling process by reverse circulation until it is washed clean.

10. The method for using the gravel packing tool according to claim 9, characterized in that: It also includes the following process: (7) Releasing the string and pulling out the filling inner pipe: Since there is no pressure inside the anchor mechanism of the gravel packing tool, the anchor shoe (4) retracts under the action of the spring (5), and then hydraulic or mechanical string release is carried out. ① Hydraulic string release: Drop the string release ball (13). The string release ball (13) settles to the string release seat (14) under small-displacement pumping or gravity. Pressurize from the inside of the tubing until the string release shear pin (16) is cut off. The string release seat (14) descends, releasing the lock block (15). When the tubing string is lifted, the lower retaining claw (11.1) of the string release joint (11) retracts, causing the connecting sleeve (25) between the filling inner pipe string and the filling outer pipe string to lose restraint and achieve string release. ②Mechanical release: There is no pressure inside the anchoring mechanism of the gravel packing tool. The anchor shoe (4) retracts under the action of the spring (5). Rotate the tubing connected to the upper part of the gravel packing tool clockwise from the surface, driving the anchoring mechanism, the upper central pipe (7) and the release joint (11) to rotate clockwise. Since the filling outer pipe string is fixed by the gravel filled in the screen pipe connected to the lower part and does not rotate, the release joint (11) is released by the clockwise rotation and disengagement of the reverse thread at the lower part; ⑧Sand control production: After the inner filling pipe string is pulled out, without the extrusion of the inner filling pipe (21), the closing sleeve (33) moves upward under the action of the closing spring (34) to close the filling channel (37); The cup (30) seals the annulus between the gravel packing tool and the casing (36), and the fluid in the oil and gas layer rises through the gravel layer and the screen pipe filled at the lower part of the gravel packing tool, realizing sand control production.

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