Rotatable releasing well completion pipe string and method for shaft reconstruction

Abstract

In the tubular column, a releasing short section is in buckled connection with a drill rod connector, an anti-rotation connector and the releasing short section form a sealing cavity through a sealing assembly composed of a first sealing ring and an adapter, the upper portion of the adapter is connected with the releasing short section through a left-hand buckle, and the lower portion of the adapter is in right-hand buckle connection with the upper portion of a tubing short section. The vulcanization coupling is connected with the lower portion of the tubing nipple in a buckled mode, and the vulcanization coupling and the tubing nipple are sealed through the vulcanization piece. The high-pressure-bearing sleeve is connected with the rotatable releasing suspension device and extends in a thick-wall sleeve of a shaft, the two-stage bumping seat is connected with the high-pressure-bearing sleeve, the float collar is arranged on the side, away from the rotatable releasing suspension device, of the two-stage bumping seat and connected with the high-pressure-bearing sleeve, and the eccentric guide shoe is arranged on the side, away from the two-stage bumping seat, of the float collar and connected with the high-pressure-bearing sleeve. The tubular column can rotate in the tripping-in process and is small in size and high in pressure bearing capacity.

Description

Technical Field

[0001] This invention relates to the field of shale oil and gas well downhole operations technology, and in particular to a rotatable drop-out completion string and method for wellbore reconstruction. Background Technology

[0002] Due to factors such as deep burial of shale oil and gas, formation creep shearing of casing, interference from adjacent well fracturing, and complex engineering, the number of wells with casing damage and production stoppages is gradually increasing, seriously affecting wellbore integrity and becoming one of the bottleneck problems restricting the economic development of shale gas. Casing damage mostly occurs in the same well or adjacent wells during the fracturing and stimulation stage, and the main types include diameter reduction and breakage, which basically cannot meet the requirements for continued fracturing or production. Therefore, wellbore repair and reconstruction are urgently needed. Wellbore repair mainly adopts technologies such as high-efficiency channel milling, high-pressure expansion tube patching, and casing consolidation for long sections of casing damage to rebuild the wellbore. For wells with long sections of casing damage, casing consolidation technology is used to rebuild the wellbore. The main problems with the existing completion strings used for secondary completion within the casing are:

[0003] (1) It cannot be rotated during the lowering process, resulting in low throughput in the repair well for thick-walled casing damage.

[0004] (2) The repaired product cannot meet the high pressure requirements of fracturing.

[0005] (3) Shale gas horizontal wells are mostly 139.7mm high-grade steel (BG125) thick-walled (12.7mm) casings, and the application of conventional tools in thick-walled casings (inner diameter 114.3mm) is limited.

[0006] To meet the requirements of well fracturing and restoration of oil and gas well productivity, small-sized, high-pressure-bearing, rotatable, release-type suspension devices and high-pressure-bearing threaded tubing are needed to complete wellbore reconstruction. This provides a new approach for subsequent fracturing in shale oil and gas well repair.

[0007] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a rotatable, drop-out completion string and method for wellbore reconstruction. The string can be rotated during the running-in process, solving the problem of difficult string running in multi-section casing-modified wells in horizontal wells. The high-pressure-bearing threaded string meets the high-pressure requirements of fracturing operations. Reconstructing the casing-modified shale oil and gas wellbore restores its integrity and provides a guarantee for resuming production.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A rotatable drop-out completion string for wellbore reconstruction according to the present invention includes:

[0011] A rotatable, drop-and-hold suspension device, comprising,

[0012] The drill pipe connector has drill pipe threads for connecting the drill pipe.

[0013] The release section is connected to the drill pipe joint via a snap-fit ​​connection. The upper part of the release section is a reverse snap-fit ​​connection for the lower part of the drill string after forward rotation.

[0014] The straightening ring, whose buckle connects to the release section,

[0015] An anti-adaptor connector connects to the release section via a shear pin. The shear pin has a limiting groove. The anti-adaptor connector forms a sealed cavity with the release section via a sealing assembly consisting of a first sealing ring and a variable buckle. The upper part of the variable buckle connects to the release connector via a reverse buckle.

[0016] A steel ball, positioned between the anti-adaptor and the release section, enters the limiting groove and is stopped during the upward movement of the anti-adaptor after shearing the shear pin under pressure.

[0017] The lower part of the oil pipe sub-section is connected to the upper part of the oil pipe sub-section via a positive snap.

[0018] A vulcanized coupling is fastened to the lower part of the oil pipe section, and the vulcanized coupling forms a seal with the oil pipe section through the vulcanized component;

[0019] A high-pressure casing, which is connected to the rotatable release suspension device and extends within a thick-walled casing in the wellbore.

[0020] The two-stage pressure-bearing seat connects to the high-pressure-bearing sleeve.

[0021] At least one floating hoop is located on the side of the dual-stage impact seat away from the rotatable release suspension device and connected to the high-pressure sleeve.

[0022] An eccentric guide shoe is located on the side of the float hoop away from the double-stage impact seat and is connected to the high-pressure sleeve.

[0023] In the aforementioned rotatable hand-release completion string for wellbore reconstruction, a hollow rubber plug is sealed to the vulcanized coupling via a third sealing ring.

[0024] In the aforementioned rotatable hand-release completion string for wellbore reconstruction, a shear pin is disposed between the vulcanized coupling and the hollow rubber plug.

[0025] In the aforementioned rotatable hand-release completion string for wellbore reconstruction, the lower part of the hollow rubber plug is provided with a fourth sealing ring and a retaining ring.

[0026] In the aforementioned rotatable hand-release completion string for wellbore reconstruction, the retaining ring is a backflow prevention ring.

[0027] In the aforementioned rotatable hand-release completion string for wellbore reconstruction, the tubing short section includes an inner tubing short section and an outer tubing short section.

[0028] In the aforementioned rotatable release completion string for wellbore reconstruction, the rotatable release suspension device has a centrally symmetrical structure.

[0029] In the aforementioned rotatable hand-release completion string for wellbore reconstruction, three float hoops are sequentially connected in series between the double-stage pressure seat and the eccentric guide shoe in the high-pressure casing.

[0030] In the aforementioned rotatable hand-drop completion string for wellbore reconstruction, the rotatable hand-drop completion string for wellbore reconstruction has a centrally symmetrical structure.

[0031] A working method for a rotatable, drop-off completion string for wellbore reconstruction includes,

[0032] The rotatable drop-out completion string is lowered to the well depth for well reconstruction. If it encounters resistance during the lowering process, the rotatable drop-out completion string is circulated and rotated to pass through.

[0033] After the circulation is normal, the pressure ball is put in, the pump is turned on to replace it, and after the pressure ball is in place, the pressure is increased to 15MPa. The anti-rotation mechanism of the suspension is disengaged, and the pressure is continued to be increased to 22MPa. The inner sleeve of the double-stage pressure seat 20 is removed to establish circulation.

[0034] After stopping the pump, place the drill string at the neutral point, rotate the drill string clockwise 20 times, and then rotatably release the release suspension device from the release section.

[0035] The drilling tool is lowered by 200kN, equipped with an adjustable length drilling tool, and cement head cementing is installed.

[0036] After the cement grout is injected, the pressure plug is used to replace it. When the composite plug reaches the double-stage pressure seat, the pressure increases, the pressure is held up, the pump is stopped and the water is drained.

[0037] After cementing is completed and everything is normal, pull up and send in the drill string so that the center tube is detached from the rotatable release suspension device.

[0038] Excess cementing fluid is circulated out of the annulus;

[0039] Raise the drill string and shut in the well to allow the water to settle.

[0040] In the above technical solution, the rotatable drop-out completion string and method for wellbore reconstruction provided by this invention have the following beneficial effects: The rotatable drop-out completion string for wellbore reconstruction solves the problem of running completion strings into thick-walled, small-casing wells. It ensures that shale oil and gas repair wells meet high-pressure fracturing requirements after wellbore reconstruction. It is suitable for volumetric fracturing after running φ88.9mm casing in 5-1 / 2" small-bore, thick-walled wellbore reconstruction. The rotatable drop-out completion string for wellbore reconstruction improves the success rate of shale oil and gas wellbore repair, meets the requirements of subsequent fracturing operations, and thus avoids the adverse consequences of other repair measures. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0042] Figure 1 This is a schematic diagram of the arrangement of a rotatable hand-drop completion string for wellbore reconstruction, provided as an embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram of a rotatable hand-drop completion string for wellbore reconstruction, provided as an embodiment of the present invention.

[0044] Figure 3 for Figure 2 An enlarged structural schematic diagram of a rotatable release suspension device at the circle of a rotatable release completion string for wellbore reconstruction, provided in one embodiment of the present invention.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1. Drill pipe joint; 2. Release stub; 3. Centralizing ring; 4. Anti-rotation joint; 5. Shear pin; 6. Steel ball; 7. First sealing ring; 8. Second sealing ring; 9. Variable thread; 10. Inner tubing stub; 11. Outer tubing stub; 12. Vulcanized coupling; 13. Third sealing ring; 14. Shear pin; 15. Hollow rubber plug; 16. Fourth sealing ring; 17. Snap ring; 18. Rotatable release suspension device; 19. High-pressure casing; 20. Double-stage pressure seat; 21. First float collar; 22. Second float collar; 23. Third float collar; 24. Eccentric guide shoe; 25. Thick-walled casing. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that similar reference numerals and letters in the following drawings indicate similar items. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0048] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0049] See Figure 1-3 As shown, in one embodiment, a rotatable drop completion string for wellbore reconfiguration according to the present invention includes,

[0050] Rotatable drop-off suspension device 18, which includes,

[0051] Drill pipe connector 1, which is provided with drill pipe thread for connecting drill pipe.

[0052] The release section 2 is connected to the drill pipe joint 1. The upper part of the release section 2 is a reverse connection for the lower part of the drill string after forward rotation.

[0053] The straightening ring 3 is fastened to the release section 2.

[0054] The anti-adaptor 4 is connected to the release section 2 via a shear pin 5. The shear pin 5 has a limiting groove. The anti-adaptor 4 forms a sealed cavity with the release section 2 through a sealing assembly consisting of a first sealing ring 7 and a variable buckle 9. The upper part of the variable buckle 9 is connected to the release connector via a reverse buckle.

[0055] Steel ball 6 is located between the anti-adaptor 4 and the release section 2. When the anti-adaptor 4 moves upward after shearing the shear pin 5 under pressure, steel ball 6 enters the limiting groove for limitation.

[0056] The lower part of the variable snap 9 is connected to the upper part of the oil pipe short section via a positive snap.

[0057] Vulcanized coupling 12 is fastened to the lower part of the oil pipe short section, and the vulcanized coupling 12 forms a seal with the oil pipe short section through the vulcanized element;

[0058] A high-pressure casing 19, which connects to the rotatable release suspension device 18 and extends within the thick-walled casing 25 of the wellbore, is further connected by threads to the rotatable release suspension device and the two-stage impact seat.

[0059] The double-stage pressure-bearing seat 20 is connected to the high-pressure-bearing sleeve 19.

[0060] At least one floating hoop is located on the side of the double-stage impact seat 20 away from the rotatable release suspension device 18 and connected to the high-pressure bearing sleeve 19.

[0061] An eccentric guide shoe 24 is located on the side of the float hoop away from the double-stage impact seat 20 and is connected to the high-pressure bearing sleeve 19. When the lowered tailpipe encounters resistance, the forward rotation of the pipe column allows for the rotation of the rotatable release suspension device.

[0062] In a preferred embodiment of the rotatable hand-drop completion string for wellbore reconstruction, the hollow rubber plug 15 is sealed to the vulcanized coupling 12 via a third sealing ring 13.

[0063] In a preferred embodiment of the rotatable hand-release completion string for wellbore reconstruction, the shear pin 14 is disposed between the vulcanized coupling 12 and the hollow rubber plug 15.

[0064] In a preferred embodiment of the rotatable hand-release completion string for wellbore reconstruction, the lower part of the hollow rubber plug 15 is provided with a fourth sealing ring 16 and a retaining ring 17.

[0065] In a preferred embodiment of the rotatable hand-release completion string for wellbore reconstruction, the retaining ring 17 is a backflow prevention ring.

[0066] In a preferred embodiment of the rotatable drop completion string for wellbore reconstruction, the tubing short section includes an inner tubing short section 10 and an outer tubing short section 11.

[0067] In a preferred embodiment of the rotatable release completion string for wellbore reconstruction, the rotatable release suspension device 18 has a centrally symmetrical structure.

[0068] In a preferred embodiment of the rotatable hand-release completion string for wellbore reconstruction, three float rings are connected in series between the double-stage pressure seat 20 and the eccentric guide shoe in the high-pressure casing 19.

[0069] In a preferred embodiment of the rotatable release completion string for wellbore reconstruction, the rotatable release completion string for wellbore reconstruction has a centrally symmetrical structure.

[0070] A working method for a rotatable, drop-off completion string for wellbore reconstruction includes,

[0071] The rotatable, drop-out completion string is run to the well depth for well reconstruction. If obstruction is encountered during the run, the rotatable, drop-out completion string is circulated and rotated to pass through. The top drive or rotary table rotates the string. Figure 3 Because the middle anti-adaptor 4 and the lower part are interlocked, they will cause the lower tube column to rotate as a whole. Once the interlocking parts of the anti-adaptor 4 and the buckle 9 are disengaged, the release short section 2 and the buckle 9 will release the lower tube column after rotating for a sufficient number of turns.

[0072] After the circulation is normal, insert the pressure briquette, start the pump to replace it, and after the pressure briquette is in place, pressurize to 15MPa. The suspension anti-rotation mechanism will then disengage. Figure 3 When the anti-adaptor 4 and the variable buckle 9 in the middle are relatively displaced, they are disengaged. Continue to pressurize to 22MPa, and the inner sleeve of the double-stage impact seat 20 is knocked off to establish a cycle.

[0073] After stopping the pump, place the drill string at the neutral point, rotate the drill string 20 times clockwise, and release the rotatable release suspension device 18 from the release short section 2.

[0074] The drilling tool is lowered by 100-150kN, equipped with an adjustable length drilling tool, and cement head cementing is installed.

[0075] After the cement grout is injected, the pressure plug is used to replace it. When the composite plug reaches the double-stage pressure seat 20, the pressure increases, the pressure is suppressed, the pump is stopped and the water is drained.

[0076] After cementing is completed and everything is normal, the drill string is pulled up and sent in, so that the center tube is disengaged from the rotatable release suspension device 18;

[0077] Excess cementing fluid is circulated out of the annulus;

[0078] Raise the drill string and shut in the well to allow the water to settle.

[0079] In one embodiment, a small-sized, high-pressure-bearing, rotatable, drop-off completion string is used to address wellbore reconstruction in thick-cased shale oil and gas wells, restoring wellbore integrity and meeting the wellbore conditions for fracturing and re-production. Existing small-sized hangers cannot meet the requirements for running the completion string into thick-cased wells, and they cannot rotate during the running process. Furthermore, they are prone to encountering obstructions in shale oil and gas wells with numerous casing deformation points, making it difficult to pass through these obstruction points without rotating the string. A small-sized, high-pressure-bearing, rotatable, drop-off suspension device 18 for wellbore reconstruction solves the wellbore reconstruction problem in shale oil and gas wells with casing damage: First, a rotatable drop-off suspension device 18 is designed so that the running tailpipe can rotate when encountering obstruction, ensuring the string can smoothly reach the bottom; second, a high-pressure-bearing thread is designed to ensure the string's pressure-bearing capacity meets the fracturing pressure requirements; and third, an eccentric guide is designed to easily pass through obstruction points and guide the string to continue running. The rotatable release completion string for wellbore reconstruction includes a rotatable release suspension device 18, a 5-1 / 2" thick-walled casing, a 3-1 / 2" high-pressure casing 19, a double-stage pressure seat 20, a first float collar 21, a second float collar 22, a third float collar 23, and an eccentric guide shoe 24. This effectively solves the problems of string insertion and pressure bearing during wellbore reconstruction in shale gas thick-walled casing, and better achieves the construction objective of repair well fracturing. In the rotatable release suspension device 18, the drill pipe joint 1 is made of 42CrMo material, and the upper part is machined with 2-7 / 8" AP... The drill pipe joint 1 is threaded and connected to the drill pipe before the completion tubing is inserted into the well. The drill pipe joint 1 connects to the release sub 2 via a threaded connection. The upper part of the release sub 2 has a reverse thread; after forward rotation, the lower tubing can be released. The release sub 2 joint is made of 42CrMo material and its lower part connects to the centralizing ring 3, anti-rotation connector 4, variable thread 9, and tubing sub. The centralizing ring 3 is made of 45# steel and connects to the release sub 2 via a threaded connection. The anti-rotation connector 4 connects to the release sub 2 via a shear pin 5. A sealing assembly consisting of a first sealing ring 7 and a variable thread 9 connects to the release sub 2. 2. A sealed cavity is formed. Further, the sealing assembly also includes a second sealing ring 8 located between the first sealing ring and the variable coupling 9. During the upward movement of the steel ball 6 after the anti-transfer joint 4 shears off the shear pin 5 under pressure, the steel ball 6 enters the limiting groove left at the pin and is limited. The variable coupling 9 is made of 42CrMo material, with its upper part connected to the release stub 2 via a reverse coupling, and its lower part connected to the tubing stub via a forward coupling. The lower part of the tubing stub is connected to the vulcanized coupling 12 via a coupling. The vulcanized coupling 12 forms a seal with the 3-1 / 2" tubing stub through the vulcanized component. When the drill pipe rubber plug descends and overlaps with the hollow rubber plug 15, it shears off the shear pin 14 under high pressure. The anti-backflow ring is made of 60Si2Mo material; when the composite rubber plug reaches the position of the double-stage pressure seat 20, it prevents backflow.

[0080] Finally, it should be noted that the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0081] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A rotatable, drop-out completion string for wellbore reconfiguration, characterized in that, It includes, A rotatable, drop-and-hold suspension device, comprising, The drill pipe connector has drill pipe threads for connecting the drill pipe. The release section is connected to the drill pipe joint via a snap-fit ​​connection. The upper part of the release section is a reverse snap-fit ​​connection for the lower part of the drill string after forward rotation. The straightening ring, whose buckle connects to the release section, An anti-adaptor connector connects to the release section via a shear pin. The shear pin has a limiting groove. The anti-adaptor connector forms a sealed cavity with the release section via a sealing assembly consisting of a first sealing ring and a variable buckle. The upper part of the variable buckle connects to the release connector via a reverse buckle. A steel ball, positioned between the anti-adaptor and the release section, enters the limiting groove and is stopped during the upward movement of the anti-adaptor after shearing the shear pin under pressure. The lower part of the oil pipe sub-section is connected to the upper part of the oil pipe sub-section via a positive snap. A vulcanized coupling is fastened to the lower part of the oil pipe section, and the vulcanized coupling forms a seal with the oil pipe section through the vulcanized component; A high-pressure casing, which is connected to the rotatable release suspension device and extends within a thick-walled casing in the wellbore. The two-stage pressure-bearing seat connects to the high-pressure-bearing sleeve. At least one floating hoop is located on the side of the dual-stage impact seat away from the rotatable release suspension device and connected to the high-pressure sleeve. An eccentric guide shoe is located on the side of the float hoop away from the double-stage impact seat and is connected to the high-pressure sleeve.

2. The rotatable drop-out completion string for wellbore reconstruction according to claim 1, characterized in that, The hollow rubber plug is sealed to the vulcanized coupling via a third sealing ring.

3. The rotatable drop-out completion string for wellbore reconstruction according to claim 2, characterized in that, The shear pin is located between the vulcanized coupling and the hollow rubber plug.

4. A rotatable, drop-out completion string for wellbore reconstruction according to claim 2, characterized in that, The lower part of the hollow rubber stopper is provided with a fourth sealing ring and a retaining ring.

5. A rotatable, drop-out completion string for wellbore reconstruction according to claim 4, characterized in that, The retaining ring is a backflow prevention ring to prevent backflow.

6. A rotatable, drop-out completion string for wellbore reconfiguration according to claim 1, characterized in that, The tubing stub consists of an inner tubing stub and an outer tubing stub.

7. A rotatable, drop-out completion string for wellbore reconstruction according to claim 1, characterized in that, The rotatable hand-dropping suspension device has a centrally symmetrical structure.

8. A rotatable, drop-out completion string for wellbore reconstruction according to claim 1, characterized in that, Three floating hoops are connected in series in the high-pressure sleeve between the double-stage impact pressure seat and the eccentric guide shoe.

9. A rotatable, drop-out completion string for wellbore reconfiguration according to claim 1, characterized in that, The wellbore reconstruction uses a rotatable, drop-out completion string with a centrally symmetrical structure.

10. A method for using a rotatable, drop-off completion string for wellbore reconstruction according to any one of claims 1-9, characterized in that, It includes, The rotatable drop-out completion string is lowered to the well depth for well reconstruction. If it encounters resistance during the lowering process, the rotatable drop-out completion string is circulated and rotated to pass through. After the circulation is normal, the pressure ball is put in, the pump is turned on to replace it, and after the pressure ball is in place, the pressure is increased to 15MPa. The anti-rotation mechanism of the suspension is disengaged, and the pressure is continued to be increased to 22MPa. The inner sleeve of the double-stage pressure seat 20 is removed to establish circulation. After stopping the pump, place the drill string at the neutral point, rotate the drill string clockwise 20 times, and then rotatably release the release suspension device from the release section. The drilling tool is lowered by 100-150kN, equipped with an adjustable length drilling tool, and cement head cementing is installed. After the cement grout is injected, the pressure plug is used to replace it. When the composite plug reaches the double-stage pressure seat, the pressure increases, the pressure is held up, the pump is stopped and the water is drained. After cementing is completed and everything is normal, pull up and send in the drill string so that the center tube is detached from the rotatable release suspension device. Excess cementing fluid is circulated out of the annulus; Raise the drill string and shut in the well to allow the water to settle.

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