Gravel filling tool and method of use

Abstract

The present invention relates to the technical field of sand control completion in oil production, and in particular to a gravel packing tool and its use method. The technical solution comprises a release mechanism, an anchoring mechanism, an oil casing annulus sealing mechanism, and a filling conversion mechanism. The lower end of the anchor body of the anchoring mechanism is connected to the upper central pipe, a liner is provided on the inner side of the anchor body, and multiple sets of pressure plates and anchor shoe grooves are provided on the outer wall of the anchor body, with springs provided between the anchor shoes and the pressure plates. A cylinder sleeve and a spacer ring are provided on the outer side of the upper central pipe, a locking ring is provided on the lower end of the anchor body, an adjusting ring, a leather cup pressure cap, and a leather cup are installed on the outer wall of the outer central pipe, and the outer side of the leather cup pressure cap is connected to the lower end of the cylinder sleeve via a second shear pin. The beneficial effect of the present invention is that the present invention can achieve safe downhole operation, pipe string anchoring, annulus high-pressure sealing, filling and backwashing, and other working mode conversions through a single trip of the tubing string, realizing both mechanical and hydraulic release modes, with a simple structure, relatively few physical parts, low processing volume, and low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of sand control and completion in petroleum production, and in particular to a gravel packing tool and a use method thereof. Background Art

[0002] For sandstone reservoirs, oil and gas wells often produce sand during the exploitation process, resulting in low production or even shutdown. Therefore, such oil and gas wells require sand control completion before they are put into production. Gravel packing sand control has become the leading technology in a series of sand control technologies due to its long effective period and high seepage capacity. Gravel packing tools are the key tools to achieve gravel packing sand control technology. At present, conventional gravel packing tools still have the following shortcomings in their application:

[0003] (1) Conventional gravel packing tools use piston-seated rubber cylinders to achieve casing annulus sealing; piston-seated anchor slips to achieve high-pressure anchoring of the tubing string; and combined filling conversion tools have multiple flow channels to achieve formation filling, circulation filling, and reverse circulation washing and sand flushing. This results in a complex tool structure and high cost. In addition, under limited wellbore size, the size of the sand adding channel is limited, making it difficult to meet the requirements of large-volume, high-sand-ratio formation filling and sand control.

[0004] (2) Conventional gravel packing tools only use a mechanical release method of rotating inverted buckles. The main reason is that if hydraulic release is used, during the filling and sand control squeezing construction process, the squeezing pressure may fluctuate or be abnormal, leading to premature release, failure of the sealing of the inner and outer pipes of the filling and sand control, and the squeezed mortar entering the wall between the inner and outer pipes of the sand control, causing the sand to be stuck in the sand control inner pipe later, leading to oil well overhaul operations. However, this mechanical release method brings the problem of difficulty in releasing the tool for filling and sand control operations in complex wells such as medium-deep wells, high-angle wells, and horizontal wells;

[0005] (3) Conventional gravel packing tools retain well components including slip anchors, rubber cartridge seals and other mechanisms. Mechanically hard-stuck slip anchors often get stuck or blocked during later maintenance when pulling out the filter and sand control pipe string, increasing the risk of overhaul operations and the cost of operations.

[0006] In order to solve the above problems, a gravel packing tool with a simple structure, fewer well-retaining parts, and integrated mechanical and hydraulic release and a method of use are proposed. Summary of the Invention

[0007] The purpose of the present invention is to address the above-mentioned defects in the prior art and provide a gravel packing tool and a method of use. In one trip of the tubing string, a variety of working conditions can be converted, including safe downhole operation, tubing string anchoring, annulus high-pressure sealing, filling and backwashing. Both mechanical and hydraulic release modes are realized. The entire tool set has a simple structure, relatively few physical parts, small processing volume, and low cost.

[0008] The present invention relates to a gravel packing tool, the technical solution of which is as follows: comprising a release mechanism, an anchoring mechanism, an oil casing annulus sealing mechanism, and a filling conversion mechanism; the anchoring mechanism comprising an anchor body, a pressure plate, an anchor shoe, a spring, and a liner; the lower end of the anchor body is connected to the upper central pipe; the inner side of the anchor body is provided with a liner; the outer wall of the anchor body is provided with multiple groups of pressure plates and anchor shoe grooves; the anchor shoes are installed in the anchor shoe grooves; a spring is provided between the anchor shoe and the pressure plate; during the gravel packing process, the anchor shoe cooperates with the pressure plate to anchor the tool to the inner wall of the casing;

[0009] The oil casing annulus sealing mechanism includes a locking ring, a cylinder sleeve, a spacer ring, an outer center pipe, an adjusting ring, a leather cup pressure cap, a second shear pin, and a leather cup. The cylinder sleeve and the spacer ring are provided on the outer side of the upper center pipe, the locking ring is provided on the lower end of the anchor body, the adjusting ring, the leather cup pressure cap and the leather cup are installed on the outer wall of the outer center pipe, the upper side of the leather cup pressure cap is provided with an adjusting ring, the lower side is provided with a leather cup, and the outer side of the leather cup pressure cap is connected to the lower end of the cylinder sleeve through the second shear pin;

[0010] The filling conversion mechanism includes an inner filling tube, an outer filling sleeve, a diverter sleeve, a door closing sleeve, and a door closing spring. The outer wall of the inner filling tube is provided with an inner filling hole, and a diverter sleeve is installed on the outer wall of the inner filling tube. An outer filling sleeve is provided on the outer side of the diverter sleeve, and an outer filling hole is provided on the outer filling sleeve. The lower end of the outer filling sleeve is connected to the lower joint, and a door closing spring is installed in the inner cavity of the lower joint. The upper part of the door closing spring is connected to the door closing sleeve, and the door closing sleeve is located between the inner filling tube and the diverter sleeve. The door closing spring is squeezed by the lower end of the inner filling tube, so that the door closing sleeve is located on the lower side of the inner filling hole and the outer filling hole, and the inner filling hole and the outer filling hole form a connected filling channel.

[0011] Preferably, the above-mentioned release mechanism includes a release joint, a locking block seat, a release steel ball, a release ball seat, a locking block, a release shear nail, an inner center tube, and a connecting sleeve. The inner cavity of the inner center tube is provided with a release ball seat for supporting the release steel ball. A groove is provided on the upper outer side of the release ball seat. The outer wall of the inner center tube is connected to the locking block seat through the release shear nail. The locking block is installed on the locking block seat. The outer side of the locking block seat is installed with a release joint, the lower end of the release joint is connected to the connecting sleeve, and the lower end of the connecting sleeve is connected to the outer center tube.

[0012] Preferably, the above-mentioned oil casing annulus sealing mechanism also includes a sealing steel ball, a first shear pin, and a ball seat. The ball seat is connected to the upper part of the inner wall of the inner filling tube through the first shear pin, and the ball seat is used to support the sealing steel ball.

[0013] Preferably, the above-mentioned filling conversion mechanism also includes a baffle, an inner lower joint, and a circulating ball. The lower part of the inner filling tube is provided with a baffle and an inner lower joint, and 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 limited by the baffle.

[0014] Preferably, a limiting protrusion is provided on the top of the inner wall of the diverter sleeve, and when the door closing sleeve returns to its original position, the upper end contacts and cooperates with the limiting protrusion.

[0015] Preferably, the two ends of the pressure plate are fixed to the outer wall of the anchor body by bolts, and the outer end of the anchor shoe is provided with two groups of semicircular fixing teeth, which contact the pressure plate through a spring at the center of the anchor shoe, and the inner end of the anchor shoe contacts the outer wall of the liner to achieve positioning.

[0016] Preferably, a lock buckle is provided on the top of the cylinder sleeve, which is connected to the lock ring through the lock buckle, and a limiting inner protrusion is provided on the lower part of the lock buckle, which realizes positioning by cooperating with the bottom end of the anchor body through the limiting inner protrusion; the lower end inner wall of the cylinder sleeve and the leather cup pressure cap are connected by a second shear nail, and the shear resistance of the second shear nail is smaller than the shear resistance of the first shear nail; the middle part of the cylinder sleeve is supported by a spacer ring.

[0017] Preferably, a pressure transmission hole is provided between the upper center tube and the cylinder sleeve, a first communicating hole is provided on the lower side of the cylinder sleeve, and a second communicating hole is provided on the outer center tube on the upper side of the adjusting ring.

[0018] The method for using the gravel packing tool mentioned in the present invention includes the following steps:

[0019] (1) Safe running: The gravel packing tool is lowered into the casing through the tubing. Since the gravel packing tool has a bidirectional flow performance from the inside to the outside, the internal and external pressures are kept consistent during the running of the gravel packing tool. Therefore, there is no sealing or anchoring, and the running is safe. At the same time, the leather cup is pre-pressed in the cylinder sleeve to ensure that the leather cup is not scratched or worn during the running process.

[0020] (2) Leather cup release, sealing the annulus: a sealing steel ball is dropped from the oil pipe at the surface wellhead, and then pressure is pumped from the surface wellhead until the second shear pin is cut. The cylinder sleeve moves upward under the action of hydraulic pressure and is fixed on the locking ring. The leather cup is exposed and seals the annulus between it and the casing;

[0021] (3) Filling channel opening: Continue to pressurize the tubing until the first shear pin is cut, and the setting steel ball and the ball seat are pressed down together to the baffle at the bottom of the filling channel, thus achieving internal and external communication of the gravel packing tool through the filling channel;

[0022] (IV) Formation filling and sand control: The casing gate is closed, and sand-carrying fluid and proppant are injected from the oil pipe at the surface wellhead. The sand-carrying fluid and proppant pass through the interior 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 flow downward into the formation to achieve formation filling and sand control. At the same time, the anchor mechanism of the gravel packing tool is compressed and opened by the anchor shoe under internal pressure, and anchored to the inner wall of the casing;

[0023] (5) Circulation filling and sand control: open the casing gate, inject sand-carrying fluid and proppant from the oil pipe at the wellhead on the ground, 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 between the casing and the screen connected to the lower part of the gravel packing tool, and the proppant remains between the screen and the casing. The sand-carrying fluid is filtered through the screen and flows into the annulus between the inner filling pipe and the lower joint through the inner lower joint, continues to move upward along the annulus between the inner filling pipe and the outer center pipe, and then along the second connecting hole of the outer center pipe and the first connecting hole of the cylinder sleeve into the annulus between the cylinder sleeve and the casing, and circulates back to the ground to realize gravel filling and sand control in the annulus between the screen and the casing. At the same time, the anchoring mechanism of the gravel packing tool is under internal pressure, and the anchor shoe is compressed and opened and anchored to the inner wall of the casing;

[0024] (6) Reverse circulation sand flushing: reverse circulation sand flushing from the annulus between the tubing and casing. The liquid flows downward through the cylinder sleeve of the gravel packing tool through the first connecting hole and the second connecting hole into the annulus between the inner center pipe and the outer center pipe, and continues downward through the wall space between the outer packing sleeve and the diversion sleeve, and then through the third connecting hole into the inner cavity of the inner lower joint. The circulating ball is pressurized to block the lower flow channel, and the liquid flows upward through the inside of the inner filling pipe until it passes through the inner cavity of the gravel packing tool and circulates back to the ground through the inside of the tubing. The gravel remaining in the tubing and the gravel packing tool during the circulation filling process is reversely circulated out of the ground until it is flushed clean.

[0025] Preferably, the method for using the gravel packing tool mentioned in the present invention further includes the following steps:

[0026] (7) Release and pull out the inner filling tube: Since there is no pressure inside the anchoring mechanism of the gravel packing tool, the anchor shoe retracts under the action of the spring, and then the hydraulic release or mechanical release is performed;

[0027] ① Hydraulic release: The release steel ball is thrown. Under the action of small displacement pumping or gravity, it sinks to the release ball seat, pressurizing the inside of the oil pipe until the release shear pins are cut off. The release ball seat moves downward and releases the locking block. When the lower part of the release joint loses the support of the locking block, the lower claw of the release joint retracts when the tubing is lifted, so that the connection sleeve of the inner and outer tubing strings is freed from constraints, thus achieving release.

[0028] ② Mechanical release: There is no pressure inside the anchoring mechanism of the gravel packing tool. The anchor shoe is retracted under the action of the spring, and the oil pipe connected to the upper part of the gravel packing tool rotates forward from the ground, driving the anchoring mechanism, upper central pipe and release joint to rotate forward. The outer filling string is fixed by the circulating gravel because the screen pipe connected to the lower part is fixed and does not rotate. The reverse buckle at the lower part of the release joint is released due to the forward rotation.

[0029] (8) Sand blocking production: After the inner filling pipe string is pulled out, in the absence 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, and the oil and gas layer fluid passes through the gravel layer and screen pipe filled at the bottom of the gravel packing tool and moves upward to achieve sand blocking production.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] (1) Structurally, the present invention realizes the design and innovation of a gravel packing tool that integrates an anchor shoe, a leather cup, and a filling, and realizes both hydraulic and mechanical release methods on the gravel packing tool. The entire tool set has a simple structure, relatively few physical parts, small processing volume, and low cost;

[0032] (2) From the functional point of view, one trip of the tubing string can achieve the integrated and multifunctional requirements of safe downhole operation, tubing string anchoring, annular high-pressure sealing, conversion between three working conditions of ground filling, annular filling and backwashing, hydraulic and mechanical reverse release, and sand blocking production. In addition, the tubing string does not need to be moved during the gravel filling process. The construction is safe, efficient, and reliable, and there is no risk of sand jamming. In addition, after the inner tubing string is pulled out, very few parts are left in the well, and there are no hard-stuck parts such as anchor shoes and slip anchors. The subsequent maintenance and filter removal and well repair operations are safer and more reliable, and have good adaptability to complex structure wells such as deep wells and horizontal wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the present invention;

[0034] Figure 2 It is a schematic diagram of the structure when safely lowered;

[0035] Figure 3 It is a schematic diagram of the structure of the leather cup releasing and sealing the annulus;

[0036] Figure 4 It is a structural diagram of the filling channel opening;

[0037] Figure 5 It is a structural diagram of formation gravel pack;

[0038] Figure 6 It is a schematic diagram of the structure of circulating gravel pack;

[0039] Figure 7 This is a schematic diagram of the structure of reverse circulation well washing and sand flushing;

[0040] Figure 8 It is a structural diagram of a throwing hand steel ball;

[0041] Figure 9 This is a structural diagram of a hydraulic release mechanism;

[0042] Figure 10 This is a schematic diagram of the structure for lifting the sand control service string;

[0043] Figure 11 This is a structural diagram of a well-retaining sand retaining tool;

[0044] In the figure above: anchor body 1, bolt 2, pressure plate 3, anchor shoe 4, spring 5, liner 6, upper center pipe 7, lock ring 8, cylinder sleeve 9, spacer ring 10, release joint 11, lock block seat 12, release steel ball 13, release ball seat 14, lock block 15, release shear pin 16, inner center pipe 17, setting steel ball 18, first shear pin 19, ball seat 20, inner filling pipe 21, baffle 22, inner lower joint 23, circulating ball 24, connection Sleeve 25, outer center tube 26, adjusting ring 27, leather cup pressure cap 28, second shear pin 29, leather cup 30, outer filling sleeve 31, diverter sleeve 32, door closing sleeve 33, door closing spring 34, lower joint 35, sleeve 36, filling channel 37, pressure transmission hole 7.1, lock buckle 9.1, limit inner protrusion 9.2, first connecting hole 9.3, lower clamping claw 11.1, third connecting hole 23.1, second connecting hole 26.1. DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0046] Example 1, with reference to Figures 1-11 The gravel packing tool mentioned in the present invention includes a release mechanism, an anchoring mechanism, an oil casing annulus sealing mechanism, and a filling conversion mechanism. The anchoring mechanism includes an anchor body 1, a pressure plate 3, an anchor shoe 4, a spring 5, and a liner 6. The lower end of the anchor body 1 is connected to the upper central pipe 7. The inner side of the anchor body 1 is provided with a liner 6. The outer wall of the anchor body 1 is provided with multiple groups of pressure plates 3 and anchor shoe grooves. The anchor shoe 4 is installed in the anchor shoe groove, and a spring 5 is provided between the anchor shoe 4 and the pressure plate 3. During the gravel packing process, the anchor shoe 4 cooperates with the pressure plate 3 to anchor the tool to the inner wall of the casing 36.

[0047] The oil casing annulus sealing mechanism includes a locking ring 8, a cylinder sleeve 9, a spacer ring 10, an outer center pipe 26, an adjusting ring 27, a leather cup pressure cap 28, a second shear nail 29, and a leather cup 30. The cylinder sleeve 9 and the spacer ring 10 are provided on the outer side of the upper center pipe 7, and the locking ring 8 is provided on the lower end of the anchor body 1. The adjusting ring 27, the leather cup pressure cap 28 and the leather cup 30 are installed on the outer wall of the outer center pipe 26. The upper side of the leather cup pressure cap 28 is provided with an adjusting ring 27, and the lower side is provided with a leather cup 30. The outer side of the leather cup pressure cap 28 is connected to the lower end of the cylinder sleeve 9 through the second shear nail 29.

[0048] The filling conversion mechanism includes an inner filling tube 21, an outer filling sleeve 31, a diverter sleeve 32, a closing sleeve 33, and a closing spring 34. The outer wall of the inner filling tube 21 is provided with an inner filling hole, and the diverter sleeve 32 is installed on the outer wall of the inner filling tube 21. The outer side of the diverter sleeve 32 is provided with an outer filling sleeve 31, and the outer filling sleeve 31 is provided with an outer filling hole. The lower end of the outer filling sleeve 31 is connected to the lower joint 35, and 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 tube 21 and the diverter sleeve 32. The closing spring 34 is squeezed by the lower end of the inner filling tube 21, so that the closing sleeve 33 is located on the lower side of the inner filling hole and the outer filling hole, and the inner filling hole and the outer filling hole form a connected filling channel 37.

[0049] Preferably, the above-mentioned release mechanism includes a release joint 11, a locking block seat 12, a release steel ball 13, a release ball seat 14, a locking block 15, a release shear nail 16, an inner center tube 17, and a connecting sleeve 25. The inner cavity of the inner center tube 17 is provided with a release ball seat 14 for supporting the release steel ball 13. The upper outer part of the release ball seat 14 is provided with a groove. The outer wall of the inner center tube 17 is connected to the lock block seat 12 through the release shear nail 16. The locking block 15 is installed on the lock block seat 12. The release joint 11 is installed on the outer side of the lock block seat 12. The lower end of the release joint 11 is connected to the connecting sleeve 25, and the lower end of the connecting sleeve 25 is connected to the outer center tube 26.

[0050] Preferably, the above-mentioned oil casing annulus sealing mechanism also includes a sealing steel ball 18, a first shear pin 19, and a ball seat 20. The ball seat 20 is connected to the upper part of the inner wall of the inner filling tube 21 through the first shear pin 19, and the ball seat 20 is used to support the sealing steel ball 18.

[0051] Preferably, the above-mentioned filling conversion mechanism also includes a baffle 22, an inner lower joint 23, and a circulating ball 24. The lower part of the inner filling tube 21 is provided with a baffle 22 and an inner lower joint 23, and a 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 limited by the baffle 22.

[0052] Preferably, a limiting protrusion is provided on the top of the inner wall of the diverter sleeve 32, and when the door closing sleeve 33 returns to its original position, the upper end contacts and cooperates with the limiting protrusion.

[0053] Preferably, the two ends of the above-mentioned pressure plate 3 are fixed to the outer wall of the anchor body 1 by bolts 2, and the outer end of the anchor shoe 4 is provided with two groups of semicircular fixing teeth. The center of the anchor shoe 4 contacts the pressure plate 3 through a spring 5, and the inner end of the anchor shoe 4 contacts the outer wall of the liner 6 to achieve positioning.

[0054] Preferably, the top of the above-mentioned cylinder sleeve 9 is provided with a lock buckle 9.1, which is connected to the lock ring 8 through the lock buckle 9.1, and the lower part of the lock buckle 9.1 is provided with a limiting inner protrusion 9.2, which is matched with the bottom end of the anchor body 1 to achieve positioning; the inner wall of the lower end of the cylinder sleeve 9 and the leather cup pressure cap 28 are connected by a second shear nail 29, and the shear resistance of the second shear nail 29 is less than the shear resistance of the first shear nail 19; the middle part of the cylinder sleeve 9 is supported by the spacer ring 10.

[0055] Preferably, a pressure transmission hole 7.1 is provided between the upper center tube 7 and the cylinder sleeve 9, a first communication hole 9.3 is provided on the lower side of the cylinder sleeve 9, and a second communication hole 26.1 is provided on the outer center tube 26 on the upper side of the adjustment ring 27.

[0056] The method for using the gravel packing tool mentioned in the present invention includes the following steps:

[0057] (1) Safe running: The gravel packing tool is lowered into the casing 36 through the oil pipe. Since the gravel packing tool has a bidirectional flow performance from the inside to the outside, the internal and external pressures are kept consistent during the running of the gravel packing tool. Therefore, there is no setting or anchoring, and the running is safe. At the same time, the leather cup 30 is pre-pressed in the cylinder sleeve 9 to ensure that the leather cup 30 is not scratched or worn during the running process.

[0058] (2) Leather cup release, sealing the annulus: A sealing steel ball 18 is dropped from the oil pipe at the surface wellhead. Then, pressure is pumped from the surface wellhead until the second shear pin 29 is sheared. The cylinder sleeve 9 moves upward under the action of hydraulic pressure and is fixed on the lock ring 8. The leather cup 30 is exposed and seals the annulus between it and the casing 36.

[0059] (3) Filling channel opening: Continue to pressurize the tubing until the first shear pin 19 is sheared off. The setting ball 18 and the ball seat 20 are pressed down together to the baffle 22 at the bottom of the filling channel 37, thus achieving internal and external communication of the gravel packing tool through the filling channel 37.

[0060] (IV) Formation filling and sand control: The casing gate is closed, and sand-carrying fluid and proppant are injected from the oil pipe at the surface wellhead. The sand-carrying fluid and proppant pass through the interior 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 flow downward into the formation to achieve formation filling and sand control. At the same time, the anchor mechanism of the gravel packing tool is compressed and opened by the anchor shoe 4 under internal pressure, and anchored to the inner wall of the casing 36;

[0061] (5) Circulation filling and sand control: Open the casing gate, inject sand-carrying fluid and proppant from the oil pipe at the wellhead on the ground, 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 between the casing 36 and the screen connected to the lower part of the gravel packing tool, and the proppant remains between the screen and the casing 36. The sand-carrying fluid is filtered by the screen and flows through the inner lower joint 23 into the annulus between the inner filling pipe 21 and the lower joint 35, continues to upward along the annulus between the inner filling pipe 17 and the outer center pipe 26, and then along the second connecting hole 26.1 of the outer center pipe 26 and the first connecting hole 9.3 of the cylinder liner 9 into the annulus between the cylinder liner 9 and the casing 36, and circulates back to the ground, realizing gravel filling and sand control in the annulus between the screen and the casing 36. At the same time, the anchoring mechanism of the gravel packing tool is compressed and opened by the internal pressure, and anchored to the inner wall of the casing 36;

[0062] (6) Reverse circulation sand flushing: Reverse circulation sand flushing is carried out from the annulus between the oil pipe and the casing 36. The liquid flows downward through the cylinder sleeve 9 of the gravel packing tool, through the first connecting hole 9.3 and the second connecting hole 26.1, into the annulus between the inner center pipe 17 and the outer center pipe 26, and continues downward, through the wall space between the outer filling sleeve 31 and the diverter sleeve 32, and then through the third connecting hole 23.1 into the inner cavity of the inner lower joint 23. The circulating ball 24 is pressurized to block the lower flow channel. The liquid flows upward through the inside of the inner filling pipe 21 until it passes through the inner cavity of the gravel packing tool and circulates back to the ground through the inside of the oil pipe. The gravel remaining in the oil pipe and the gravel packing tool during the circulation filling process is reversely circulated out of the ground until it is clean.

[0063] Preferably, the method for using the gravel packing tool mentioned in the present invention further includes the following steps:

[0064] (7) Release and pull out the filling inner tube: Since there is no pressure inside the anchoring mechanism of the gravel packing tool, the anchor shoe 4 is retracted under the action of the spring 5, and then the hydraulic release or mechanical release is performed;

[0065] ① Hydraulic release: The release steel ball 13 is thrown. Under low-displacement pumping or gravity, the release steel ball 13 sinks to the release ball seat 14, pressurizing the inside of the oil pipe until the release shear pin 16 is sheared. The release ball seat 14 moves downward, releasing the locking block 15. When the lower part of the release joint 11 loses the support of the locking block 15, the lower claw 11.1 of the release joint 11 retracts when the tubing string is lifted, so that the connection sleeve 25 of the inner and outer tubing strings is freed from the constraint, thus achieving release.

[0066] ② Mechanical release: There is no pressure inside the anchoring mechanism of the gravel packing tool. The anchor shoe 4 is retracted by the spring 5, and the oil pipe connected to the upper part of the gravel packing tool rotates forward from the ground, driving the anchoring mechanism, upper central pipe 7 and release joint 11 to rotate forward. The outer filling string is fixed by the circulating gravel because the screen pipe connected to the lower part is fixed and does not rotate. The reverse buckle at the lower part of the release joint 11 is released due to the forward rotation.

[0067] (8) Sand blocking production: After the inner filling pipe string is pulled out, in the absence of the squeezing of the inner filling pipe 21, the closing sleeve 33 moves upward under the action of the closing spring 34, closing the filling channel 37; the leather cup 30 seals the annulus between the gravel packing tool and the casing 36, and the oil and gas layer fluid passes through the gravel layer filled at the bottom of the gravel packing tool and the screen pipe and then moves upward to achieve sand blocking production.

[0068] The above descriptions are merely some preferred embodiments of the present invention. Anyone skilled in the art may be able to modify the above-described technical solutions or convert them into equivalent technical solutions. Therefore, any corresponding simple modifications or equivalent transformations based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A gravel packing tool including a release mechanism, characterized by: The invention 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 pressure plate (3), an anchor shoe (4), a spring (5), and a liner (6). The lower end of the anchor body (1) is connected to the upper center pipe (7). The inner side of the anchor body (1) is provided with a liner (6). The outer wall of the anchor body (1) is provided with multiple groups of pressure plates (3) and anchor shoe grooves. The anchor shoe (4) is installed in the anchor shoe groove, and a spring (5) is provided between the anchor shoe (4) and the pressure plate (3). During the gravel filling process, the anchor shoe (4) and the pressure plate (3) cooperate to anchor the anchor shoe to the inner wall of the casing (36). The oil casing annulus sealing mechanism comprises a locking ring (8), a cylinder sleeve (9), a spacer ring (10), an outer center tube (26), an adjusting ring (27), a leather cup pressure cap (28), a second shear pin (29), and a leather cup (30). The cylinder sleeve (9) and the spacer ring (10) are provided on the outer side of the upper center tube (7), a locking ring (8) is provided on the lower end of the anchor body (1), and an adjusting ring (27), a leather cup pressure cap (28), and a leather cup (30) are installed on the outer wall of the outer center tube (26). The upper side of the leather cup pressure cap (28) is provided with an adjusting ring (27), and the lower side is provided with a leather cup (30). The outer side of the leather cup pressure cap (28) is connected to the lower end of the cylinder sleeve (9) through the second shear pin (29); The filling conversion mechanism comprises an inner filling tube (21), an outer filling sleeve (31), a diverter sleeve (32), a door closing sleeve (33), and a door closing spring (34). The outer wall of the inner filling tube (21) is provided with an inner filling hole. The diverter sleeve (32) is installed on the outer wall of the inner filling tube (21). The outer side of the diverter sleeve (32) is provided with an outer filling sleeve (31). The outer filling hole is provided on the outer filling sleeve (31). The lower end of the outer filling sleeve (31) is connected to the lower connection. The head (35) is provided with a closing spring (34) in the inner cavity of the lower joint (35), the upper portion of the closing spring (34) is connected to the closing sleeve (33), and the closing sleeve (33) is located between the inner filling tube (21) and the diversion sleeve (32), and the closing spring (34) is squeezed by the lower end of the inner filling tube (21), so that the closing sleeve (33) is located at the lower side of the inner filling hole and the outer filling hole, and the inner filling hole and the outer filling hole form a connected filling channel (37); The release mechanism comprises a release joint (11), a locking block seat (12), a release steel ball (13), a release ball seat (14), a locking block (15), a release shear nail (16), an inner center tube (17), and a connecting sleeve (25). The inner cavity of the inner center tube (17) is provided with a release ball seat (14) for supporting the release steel ball (13). The upper outer portion of the release ball seat (14) is provided with a groove. The outer wall of the inner center tube (17) is connected to the lock block seat (12) through the release shear nail (16). The lock block (15) is installed on the lock block seat (12). The outer side of the lock block seat (12) is installed with a release joint (11). The lower end of the release joint (11) is connected to the connecting sleeve (25). The lower end of the connecting sleeve (25) is connected to the outer center tube (26). The oil casing annulus sealing mechanism further comprises a setting steel ball (18), a first shear pin (19), and a ball seat (20). The ball seat (20) is connected to the upper portion of the inner wall of the inner filling tube (21) via the first shear pin (19), and the ball seat (20) is used to support the setting steel ball (18). The filling conversion mechanism further comprises a baffle (22), an inner lower joint (23), and a circulation ball (24). The baffle (22) and the inner lower joint (23) are provided at the lower portion of the inner filling tube (21), and the circulation ball (24) is provided inside the inner lower joint (23). After the first shear pin (19) of the ball seat (20) is sheared, the baffle (22) limits the position of the ball seat (20).

2. The gravel packing tool according to claim 1, wherein: A limiting protrusion is provided on the top of the inner wall of the diverter sleeve (32), and when the door closing sleeve (33) returns to its original position, the upper end contacts and cooperates with the limiting protrusion.

3. The gravel packing tool according to claim 2, wherein: The two ends of the pressure plate (3) are fixed to the outer wall of the anchor body (1) by bolts (2), and the outer end of the anchor shoe (4) is provided with two groups of semicircular fixing teeth. The center of the anchor shoe (4) contacts the pressure plate (3) through a spring (5), and the inner end of the anchor shoe (4) contacts the outer wall of the liner (6) to achieve positioning.

4. The gravel packing tool according to claim 3, wherein: The top of the cylinder sleeve (9) is provided with a lock buckle (9.1), which is connected to the lock ring (8) through the lock buckle (9.1); the lower part of the lock buckle (9.1) is provided with a limiting inner protrusion (9.2), which is matched with the bottom end of the anchor body (1) to achieve positioning; the inner wall of the lower end of the cylinder sleeve (9) and the leather cup pressure cap (28) are connected through a second shear nail (29), and the shear resistance of the second shear nail (29) is smaller than the shear resistance of the first shear nail (19); the middle part of the cylinder sleeve (9) is supported by a spacer ring (10).

5. The gravel packing tool according to claim 4, characterized in that: A pressure transmission hole (7.1) is provided between the upper center tube (7) and the cylinder sleeve (9), a first communication hole (9.3) is provided on the lower side of the cylinder sleeve (9), and a second communication hole (26.1) is provided on the outer center tube (26) on the upper side of the adjustment ring (27).

6. The method for using the gravel packing tool according to claim 5, wherein: The following processes are included: (1) Safe running: The gravel packing tool is run into the casing (36) through the oil pipe. Since the gravel packing tool has a bidirectional flow performance from the inside to the outside, the internal and external pressures are kept consistent during the running of the gravel packing tool. Therefore, the tool will not be sealed or anchored, and safe running is achieved. At the same time, the leather cup (30) is pre-pressed in the cylinder sleeve (9), ensuring that the leather cup (30) is not scratched or worn during the running process; (2) Leather cup release, sealing the annulus: a sealing steel ball (18) is dropped from the oil pipe at the surface wellhead, and then pressure is pumped from the surface wellhead until the second shear pin (29) is cut, and the cylinder sleeve (9) moves upward under the action of hydraulic pressure and is fixed on the lock ring (8), and the leather cup (30) is exposed and seals the annulus between it and the casing (36); (3) Opening the filling channel: Continue to pressurize the oil pipe until the first shear pin (19) is cut, and the sealing steel ball (18) and the ball seat (20) are pressed down together to the baffle (22) at the bottom of the filling channel (37), thereby achieving internal and external communication of the gravel packing tool through the filling channel (37); (IV) Formation filling and sand control: The casing gate is closed, and sand-carrying fluid and proppant are injected from the oil pipe at the surface wellhead. The sand-carrying fluid and proppant pass through the interior 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 and enter the formation, thereby achieving formation filling and sand control; at the same time, the anchoring mechanism of the gravel packing tool is under internal pressure, and the anchor shoe (4) is compressed and opened, anchored to the inner wall of the casing (36); (5) Circulation filling and sand control: Open the casing gate, inject sand-carrying fluid and proppant from the oil pipe at 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 go down, enter between the casing (36) and the screen connected to the lower part of the gravel packing tool, the proppant remains between the screen and the casing (36), the sand-carrying fluid is filtered through the screen and flows through the inner lower joint (23) into the space between the inner filling pipe (21) and the lower joint (35) The annulus continues upward along the annulus between the inner filling pipe (17) and the outer center pipe (26), and then along the second connecting hole (26.1) of the outer center pipe (26) and the first connecting hole (9.3) of the cylinder sleeve (9) into the annulus between the cylinder sleeve (9) and the casing (36), and is reversely circulated to the ground, thereby achieving gravel filling and sand control in the annulus between the screen pipe and the casing (36). At the same time, the anchoring mechanism of the gravel filling tool is under internal pressure, and the anchor shoe (4) is compressed and opened, and anchored to the inner wall of the casing (36); (VI) Reverse circulation sand flushing: reverse circulation sand flushing is performed from the annulus between the tubing and the casing (36). The liquid flows downward through the cylinder sleeve (9) of the gravel packing tool, through the first connecting hole (9.3), the second connecting hole (26.1), into the annulus between the inner center pipe (17) and the outer center pipe (26), and then continues downward, through the wall space between the outer packing sleeve (31) and the diversion sleeve (32), and then through the third connecting hole (23.1) into the inner cavity of the inner lower joint (23). The circulating ball (24) is pressurized to block the lower flow channel. The liquid flows upward through the inside of the inner packing pipe (21) until it passes through the inner cavity of the gravel packing tool and circulates back to the ground through the inside of the tubing. Gravel remaining in the tubing and the gravel packing tool during the circulation filling process is reversely circulated out of the ground until it is clean.

7. The method for using the gravel packing tool according to claim 6, wherein: Also includes the following process: (7) Release and remove the filling inner tube: Since there is no pressure inside the anchoring mechanism of the gravel filling tool, the anchor shoe (4) is retracted under the action of the spring (5), and then the hydraulic release or mechanical release is performed; ① Hydraulic release: the release steel ball (13) is thrown. The release steel ball (13) sinks to the release ball seat (14) under low-displacement pumping or gravity, pressurizing the inside of the oil pipe until the release shear nail (16) is cut, and the release ball seat (14) moves downward, releasing the locking block (15); the lower part of the release joint (11) loses the support of the locking block (15), and when the pipe string is lifted, the lower claw (11.1) of the release joint (11) retracts, so that the connection sleeve (25) of the filling inner pipe string and the filling outer pipe string loses its constraint, and the release is achieved; ② Mechanical release: There is no pressure inside the anchoring mechanism of the gravel packing tool, and the anchor shoe (4) is retracted under the action of the spring (5). The oil pipe connected to the upper part of the gravel packing tool rotates forward from the ground, driving the anchoring mechanism, the upper center pipe (7) and the release joint (11) to rotate forward. The filling outer pipe string is fixed by the circulating packed gravel because the screen pipe connected to the lower part is fixed and does not rotate, so the forward rotation of the reverse buckle of the lower part of the release joint (11) is released; (8) Sand blocking production: After the inner filling pipe string is pulled out, the closing sleeve (33) moves upward under the action of the closing spring (34) without the squeezing of the inner filling pipe (21), closing the filling channel (37); the leather cup (30) seals the annulus between the gravel packing tool and the casing (36), and the oil and gas layer fluid passes through the gravel layer filled at the bottom of the gravel packing tool and the screen pipe and then moves upward to achieve sand blocking production.

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