Annular pressure-bearing tool and method for high-pressure-grade reverse circulation drilling and workover operation

Abstract

The invention belongs to the field of oil and gas exploitation, and discloses an annulus pressure-bearing tool and method for high-pressure-grade reverse circulation drilling and workover treatment, and the annulus pressure-bearing tool comprises a sealing assembly, a rotating assembly, a connecting piece and a fastening device; a traditional static sealing mode is changed into a mode that the sealing assembly and the rotating assembly are limited on the kelly bar body and move up and down along with the kelly bar, a kelly bar connector does not need to pass through the position of the sealing assembly all the time, abrasion of a sealing rubber core is reduced, the problem that the sealing rubber core is frequently damaged, punctured and leaked can be solved, and the service life of the sealing rubber core is prolonged. The active sealing mode can actively adjust the excitation pressure according to the sealing working pressure requirement and can supplement the pressure at any time, so that the sealing is more reliable; due to the arrangement of the rotating assembly, the pressure bearing capacity of the tool is further improved, the reliable annular dynamic sealing capacity under the higher pressure during reverse circulation drilling and grinding is guaranteed, the higher upward return flow speed of drilling and workover fluid in a drilling tool water hole and the higher drilling cutting carrying efficiency are provided, and the drilling and grinding time efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas extraction technology, specifically relating to the field of reverse circulation drilling and repair technology, and particularly to annular pressure bearing tools and methods for high-pressure reverse circulation drilling and repair operations. Background Technology

[0002] Currently, oil and gas field development targets deeper formations, with increasingly higher formation pressures and more complex downhole conditions, placing correspondingly higher pressure demands on well control equipment. During drilling and downhole operations, it is sometimes necessary to grind downhole debris and tools. To improve grinding efficiency, it is crucial to maintain the highest possible flow velocity of the drilling and workover fluid from the bottom of the well to the wellhead, efficiently carrying away drill cuttings. Traditional drilling and workover processes involve the drilling and workover fluid entering through the drill string's water inlet, carrying drill cuttings from the bottom of the well, and then exiting through the annulus. Because the cross-sectional area of ​​the annulus is larger than that of the drill string's water inlet, the flow velocity of the drilling and workover fluid within the annulus is low, resulting in low efficiency in carrying drill cuttings, affecting drilling efficiency, and potentially causing accidents such as stuck pipe.

[0003] Reverse circulation drilling and workover technology is an effective low-pressure, negative-pressure drilling and workover technique. This process involves injecting drilling and workover fluid into the annulus and then returning it through the drill string's water channels. Because the upward flow velocity within the drill string's water channels is higher than in direct circulation at the same downhole displacement, it efficiently removes obstructions from the wellbore and facilitates other related maintenance work. Particularly during reverse circulation drilling operations, at the same pump pressure and displacement, the cuttings carrying capacity is strong, improving drilling efficiency and making it a highly efficient downhole drilling method. Compared to direct circulation drilling and workover technology, reverse circulation drilling offers advantages such as high cuttings carrying efficiency, elimination of annular pressure loss, reduced bottomhole pressure, and reduced well leakage. It has unique advantages in handling downhole debris and tools, addressing large amounts of formation water in open-hole sections, and resolving severe well leakage problems. It is primarily used for repairing downhole tubing, wellbore, and formations.

[0004] Currently, the commonly used pressure control equipment for reverse circulation operations is the rotary control head. During operation, the rubber core seal annulus rotates simultaneously with the tubing string inside the well. By operating the choke valve of the choke manifold, a certain wellhead back pressure is maintained, and the returned drilling and workover fluid is returned to the surface through the drill string water hole, ensuring safe drilling, drilling and honing operations under wellhead pressure. Due to limitations in technology and materials, the highest pressure that can be achieved globally is currently 35 MPa for static pressure and 17.5 MPa for rotary control dynamic pressure. This means that during reverse circulation, the pump pressure can only be maintained at a maximum of about 15 MPa, which limits the discharge capacity and, consequently, the upward flow of drill cuttings within the drill string water hole, greatly restricting the application and promotion of efficient reverse circulation drilling and workover technology.

[0005] It is evident that the existing reverse circulation annular pressure bearing tool, due to its static sealing structure, restricts the dynamic pressure of rotation control, which in turn limits the discharge capacity and affects the efficiency of reverse circulation drilling and grinding operations. Summary of the Invention

[0006] This invention provides a high-pressure-level annular pressure bearing tool and method for reverse circulation drilling and workover operations, in order to solve the technical problem that existing reverse circulation annular pressure bearing tools, due to their static sealing structure, have limited rotational control dynamic pressure, which in turn limits the discharge capacity and affects the efficiency of reverse circulation drilling operations.

[0007] To achieve the above objectives, the present invention employs the following technical content: A high-pressure reverse circulation drilling and workover tool for annular pressure bearing includes a sealing assembly, a rotating assembly, a connector, and a fastening device; The sealing assembly is sleeved on the square drill pipe and is used to actively seal the annulus of the square drill pipe so that the sealing assembly can grip the square drill pipe tightly. The rotary assembly is connected below the sealing assembly and sleeved on the angular drill pipe. The rotary assembly is used to withstand abnormal axial loads to prevent damage to the annular pressure tool and to ensure the coaxiality of the annular pressure tool and the angular drill pipe. One end of the connector is connected to the rotating assembly via a fastening device, and the other end is connected to the blowout preventer.

[0008] Furthermore, the sealing assembly includes a sealing assembly housing, which is sleeved on the square drill rod and contains a driver, a hydraulic cylinder bracket, a hydraulic cylinder, and a sealing core. The hydraulic cylinder bracket is fixed to the inner wall of the sealing assembly housing, the hydraulic cylinder is fixed to the hydraulic cylinder bracket, and is connected to the output end of the driver; The sealing core is arranged along the circumference of the square drill rod and is located within the annulus of the square drill rod. The hydraulic cylinder can be squeezed and deformed by the drive to actively seal the annulus of the square drill rod, so that the sealing assembly can hold the square drill rod tightly. The bottom of the sealing assembly housing is bolted to the rotating assembly.

[0009] Furthermore, a sealing core lifting ring is connected to the top of the sealing core.

[0010] Furthermore, the rotary assembly includes a rotary assembly housing fitted onto the square drill rod, and the rotary assembly housing is provided with a thrust bearing and a centering bearing that cooperate with the square drill rod. The thrust bearing is used to withstand abnormal axial loads to prevent damage to the annular bearing tool. The centering bearing is used to ensure the coaxiality of the annular pressure bearing tool and the square drill pipe.

[0011] Furthermore, the top of the rotating assembly housing is provided with a first sealing cover and a second sealing cover; The top of the first sealing cover is connected to the bottom of the sealing assembly; the bottom of the second sealing cover is connected to a coupling seat, which is used to support the rotating assembly; The coupling seat and the connector are connected by a fastening device.

[0012] Furthermore, the connector adopts a fixed base, which has a multi-segment split structure. The uppermost segment is provided with a cavity that matches the bottom of the rotating assembly, and the lowermost segment is bolted to the blowout preventer.

[0013] Furthermore, the fastening device employs a clamp, which is fitted onto the uppermost section of the fixed seat; the clamp includes two annular clamps that can clamp and open under hydraulic pressure to achieve the fixation and separation between the rotating assembly and the fixed seat.

[0014] A method for using a high-pressure reverse circulation drilling and workover tool for annular pressure bearing operations, based on the aforementioned high-pressure reverse circulation drilling and workover tool for annular pressure bearing operations, comprising: After the sealing assembly and the rotary assembly are lowered to the connector position along with the square drill pipe, the rotary assembly and the connector are fixed together using a fastening device; The sealing assembly is used to actively seal the annulus of the square drill rod, so that the sealing assembly can hold the square drill rod tightly and perform pressurized drilling and grinding operations. After a single drill string is drilled, the sealing assembly releases the seal from the annulus of the opposite drill pipe and the rotating assembly is separated from the connecting parts by the fastening device. Lift the square drill rod and perform the drill rod connection operation; After the drill pipe connection operation is completed, the square drill pipe is lowered again for subsequent operations.

[0015] Furthermore, an external power source or a manual pressure pump is used to pressurize the hydraulic cylinder in the sealing assembly, causing the hydraulic cylinder to descend, compressing the sealing core, and clamping the square drill rod to produce a sealing effect.

[0016] Furthermore, during the drill pipe connection operation, the sealing core lifting ring at the top of the sealing core is pulled up to replace the sealing core.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a high-pressure annular pressure-bearing tool for reverse circulation drilling and workover operations. The tool includes a sealing assembly, a rotating assembly, connecting parts, and a fastening device. This tool replaces the traditional static sealing method with a sealing assembly and rotating assembly that are confined to the crisscross drill pipe body and move up and down with the crisscross drill pipe, ensuring the crisscross drill pipe joint never passes the sealing assembly position. This reduces wear on the sealing core, solves the problem of frequent damage and leakage of the sealing core, and extends its service life. Furthermore, it employs an active sealing method, which can actively adjust the activation pressure according to the sealing working pressure requirements and replenish the pressure at any time to ensure a more reliable seal. The rotating assembly further enhances the tool's pressure-bearing capacity, increases the displacement during the entire operation, ensures a reliable annular dynamic seal capacity of over 25 MPa during reverse circulation drilling, provides a higher drilling fluid return velocity in the drill string's waterhole, more efficient drill cuttings carrying capacity, and improves drilling efficiency.

[0018] Preferably, in this invention, the sealing assembly includes components such as a driver, a hydraulic cylinder bracket, a hydraulic cylinder, and a sealing core. The synergistic effect of these components enables the sealing assembly to actively seal the annulus of the drill pipe, and the sealing effect is reliable.

[0019] Preferably, in this invention, by connecting a sealing core lifting ring to the top of the sealing core, it is convenient to perform a lifting operation when the sealing core needs to be replaced, thereby improving the maintainability and service life of the tool.

[0020] Preferably, in this invention, the thrust bearing and the centering bearing inside the rotary assembly are used to withstand abnormal axial loads and ensure coaxiality, respectively. This improves the load-bearing capacity and stability of the tool and ensures the smooth progress of drilling and well repair operations.

[0021] Preferably, in this invention, a first sealing cover and a second sealing cover are respectively provided at the top and bottom of the rotating assembly housing. The first sealing cover and the second sealing cover can prevent mud from entering rotating parts such as bearings, thus ensuring the stable operation of the bearings.

[0022] Preferably, in this invention, a multi-segment split-structure mounting base is used as a connector, which facilitates connection and disassembly with the rotating assembly and blowout preventer, improving the tool's flexibility and adaptability. Preferably, in this invention, a clamp is used as a fastening device, which can clamp and open under hydraulic action, realizing the rapid fixing and separation between the rotating assembly and the fixed seat, and improving the operating efficiency and safety of the tool.

[0023] This invention also provides a method for using a high-pressure-level reverse circulation drilling and workover tool for annular pressure bearing. Based on the aforementioned high-pressure-level reverse circulation drilling and workover tool for annular pressure bearing, the specific steps include sealing, drilling, unsealing, and connecting drill pipe. This method achieves effective sealing and pressure bearing of the annulus of the drill pipe by actively sealing the drill pipe, while also being able to withstand abnormal axial loads, ensuring the coaxiality of the annular pressure bearing tool and the angular drill pipe, thus improving the safety and efficiency of drilling and workover operations and providing reliable guidance and protection for drilling and workover operations.

[0024] Preferably, in this invention, the hydraulic cylinder is pressurized by an external power source or a manual pressure pump, thereby achieving active sealing of the annulus of the opposing drill pipe by the sealing assembly. This operation method is simple, reliable, and easy to implement.

[0025] Preferably, in this invention, during the drill rod connection operation, the sealing core can be easily replaced by lifting the sealing core lifting ring. This design improves the maintainability and service life of the tool and reduces the difficulty and cost of replacing the sealing core. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a high-pressure-level reverse circulation drilling and workover tool provided in an embodiment of the present invention; Figure 2 A schematic diagram of the lifting working state of an annular pressure bearing tool for high-pressure reverse circulation drilling and workover operations provided in this embodiment of the invention; Figure 3 A schematic diagram of the rotating assembly structure of annular pressure bearing tool for high-pressure reverse circulation drilling and workover operations provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the sealing assembly structure of an annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations, provided as an embodiment of the present invention.

[0027] Figure label: 1-Rotary table, 2-Square drill pipe, 3-First sealing cover, 4-Rotating assembly, 5-Thrust bearing, 6-Centering bearing, 7-Sealing ring, 8-Second sealing cover, 9-Drill pipe coupling, 10-Blowout preventer, 11-Driver, 12-Hydraulic cylinder bracket, 13-Sealing assembly, 14-Hydraulic cylinder, 15-Sealing core lifting ring, 16-Hydraulic cylinder pressure plate, 17-Sealing core, 18-Clamp, 19-Coupling seat, 20-Fixed seat, 21-Drill pipe. Detailed Implementation

[0028] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0029] 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 some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0035] Example 1 As mentioned in the background technology, the commonly used pressure control equipment for reverse circulation operations is the rotary control head. During operation, the rubber core sealing annulus rotates simultaneously with the tubing string inside the well. By operating the choke valve of the choke manifold, a certain wellhead back pressure is maintained, and the returned drilling and workover fluid is returned to the surface through the drill string water hole, ensuring safe drilling, drilling and honing operations under wellhead pressure. Due to limitations in technology and materials, the highest pressure that can be achieved globally is currently 35 MPa for static pressure and 17.5 MPa for rotary control dynamic pressure. This means that during reverse circulation, the pump pressure can only be maintained at a maximum of about 15 MPa, which limits the discharge capacity and, consequently, the upward flow of drill cuttings within the drill string water hole, greatly restricting the application and promotion of efficient reverse circulation drilling and workover technology.

[0036] To address the aforementioned issues, this invention provides a high-pressure-rated annular pressure-bearing tool for reverse circulation drilling and workover operations. Its purpose is to meet the needs of efficient drilling processes, providing higher dynamic pressure-bearing capacity at the wellhead, thereby maximizing pump pressure and discharge during the drilling process, ensuring a higher return flow rate of the drilling fluid within the drill string's waterhole, and guaranteeing more efficient cuttings carrying capacity, thus improving drilling efficiency. This invention provides a dedicated high-pressure-rated annular pressure-bearing tool and method for reverse circulation drilling and workover operations. It can replace the rotary control head for annular sealing during drilling and workover conditions, increasing the current rated dynamic pressure-bearing capacity from 17.5 MPa to over 35 MPa, ensuring a reliable annular dynamic seal capacity of over 25 MPa during reverse circulation drilling, providing a higher return flow rate of the drilling fluid within the drill string's waterhole, more efficient cuttings carrying capacity, and improved drilling efficiency.

[0037] The following is a further detailed description of this embodiment with reference to the accompanying drawings: like Figure 1 As shown in the figure, this embodiment provides an annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations. The specific structure and connection method are as follows: This high-pressure reverse circulation drilling and workover tool for annular pressure bearing mainly consists of a sealing assembly 13, a rotating assembly 4, a clamp 18 (fastening device), and a fixing seat 20 (connector).

[0038] The sealing assembly 13 consists of a sealing assembly housing, a sealing core 17, a sealing core lifting ring 15, a driver 11, a hydraulic cylinder 14, and a hydraulic cylinder bracket 12, all installed inside the sealing assembly housing. It is bolted to the lower rotating assembly 4. Its main function is to use the driver 11 to deform the sealing core 17 through the hydraulic cylinder 14, thereby clamping the annulus of the square drill rod 2 and holding the square drill rod 2 tightly. This causes the sealing assembly 13 and the rotating assembly 4 to rotate with the square drill rod 2. The internal sealing core 17 seals the square drill rod 2 by the action of the hydraulic cylinder 14.

[0039] In this embodiment, in order to facilitate the replacement of the sealing core 17, a sealing core lifting ring 15 is provided on the top of the sealing core 17, which improves the replacement efficiency.

[0040] The rotating assembly 4 consists of a rotating assembly housing, a first sealing cover 3 on the top of the rotating assembly housing, a second sealing cover 8 on the top, and a centering bearing 6 and a thrust bearing 5 disposed inside the rotating assembly housing. Its main function is to solve the upward force when under pressure and to correct the coaxiality of the tool and the drill rod 2. The first sealing cover 3 and the second sealing cover 8 are to prevent mud from entering the rotating parts such as the bearings and to ensure the stable operation of the centering bearing 6 and the thrust bearing 5.

[0041] The clamp 18 consists of two semi-circular high-strength structural steel clamps, which are hydraulically controlled to open and close. When open, the rotating assembly 4 can pass through the clamp 18 for lifting operation and separate from the fixed seat 20; when closed, it can connect and fix the rotating assembly 4 and the fixed seat 20.

[0042] The mounting base 20 is a multi-segment split structure, and different sizes and heights of mounting base 20 can be selected to meet the needs of the site. The lower part of the mounting base 20 is connected to the annular blowout preventer 10 with bolts, and is connected to the upper part of the mounting base 20 of a suitable model with bolts or to the rotating assembly 4 with clamps 18.

[0043] This embodiment also provides a method for using an annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations, meeting the requirements of annular pressure control during reverse circulation. The square drill pipe 2 is sealed by the sealing assembly 13, and the sealing of the square drill pipe 2 is achieved through the rotating assembly 4 and the fixed seat 20. The sealing assembly 13, the rotating assembly 4, and the fixed seat 20 are reliably connected together by the clamp 18. This embodiment specifically adopts the following solution: When using this tool, when drilling to the bottom, the sealing assembly 13 and the rotating assembly 4 are always fixed on the body of the square drill pipe 2 on the drill table surface, and the fixed seat 20 is pre-installed on the wellhead blowout preventer 10.

[0044] After the sealing assembly 13 and the rotating assembly 4 are lowered to the fixed seat 20 along with the drill rod 2, the hydraulically driven clamp 18 clamps the fixed seat 20 and the rotating assembly 4, and then the machine can work normally.

[0045] At the start of the controlled-pressure drilling process, the hydraulic cylinder 14 in the sealing assembly 13 is pressurized using either manual or manual methods. This causes the hydraulic cylinder 14 to descend, compressing the sealing core 17 and causing it to grip the square drill rod 2, thus creating a seal. The pump is then started to circulate the material through the annulus. The rotation of the square drill rod 2 drives the driver 11, causing the sealing assembly 13 and the rotating assembly 4 to grip the square drill rod 2 and begin rotating under pressure. The square drill rod 2 is then slowly lowered according to the drilling progress, achieving pressurized drilling operations.

[0046] After a single drill string is drilled, the pump is stopped, the annulus is depressurized, and the square drill rod 2 is lifted to the coupling seat 19. When it reaches the drill rod coupling 9 position, the clamp 18 is opened, and the square drill rod 2, along with the sealing assembly 13 and the rotating assembly 4, is lifted and passed through the turntable 1. On the drilling platform, the single drill string connection operation is performed, and the drill rod 21 is connected. The square drill rod 2, along with the sealing assembly 13 and the rotating assembly 4, is then lowered to the drilling position. At this time, the rotating assembly 4 reaches the fixed seat 20 position. The clamp 18 can be hydraulically driven again to clamp the fixed seat 20 and the rotating assembly 4. The pump is then started to restore the annulus pressure, and drilling and grinding can begin. Repeating this operation can achieve pressurized circulating drilling and grinding operations. (During this process, a semi-sealed gate blowout preventer can be used to seal the drill rod to maintain a certain annulus pressure during the single drill string connection process.)

[0047] Therefore, this embodiment provides a high-pressure-rated annulus pressure-bearing tool for reverse circulation drilling and workover operations, suitable for reverse circulation drilling and workover and drilling conditions with pressurized annulus. It innovates the sealing method based on the original rotary control head, improving pressure-bearing capacity, and innovates the drilling process. The entire tool set is easy to install and safe to operate. Key innovations include at least the following: By releasing the pressure of the sealing core using a hydraulic cylinder, wear on the sealing core can be reduced, effectively solving the problem of leakage due to core damage. The tool provided in this embodiment changes the original dynamic seal to a static seal, transforming a passive seal into an active seal. It eliminates the need for rotational control pressure (17.5 MPa) and linearly increases the pressure control level to 35 MPa. More specific innovations are as follows: First, the innovative annular sealing method: This invention can replace the rotary control head for reverse circulation pressure control drilling and milling. Its sealing method is changed to a sealing assembly and a rotary assembly that are limited to the square drill rod body. It can be directly lifted to the drill table surface with the square drill rod body, always keeping the square drill rod joint from passing through the sealing assembly position, reducing wear on the sealing core, solving the problem of frequent damage and leakage of the sealing core, and extending the service life of the sealing core.

[0048] Secondly, it improves the pressure-bearing capacity of reverse circulation drilling: Reverse circulation drilling is no longer limited by the rated pressure of the dynamic seal of the rotary control head, which is only 17.5 MPa, and the actual working pressure can only reach 10-15 MPa. This invention changes the original rotary control head sealing tool, which relied on the passive deformation of the sealing rubber core to generate a seal, to a hydraulic cylinder that actively squeezes and deforms the sealing rubber core to tighten the square drill rod, thereby increasing the dynamic pressure-bearing capacity to 35 MPa. Under the same conditions, it can increase the reverse circulation displacement by 2-3 times and simultaneously increase the sand-carrying return flow rate of the drilling and workover fluid by 2-3 times, which can greatly improve the efficiency of reverse circulation drilling operations.

[0049] Third, innovative sealing activation method: This invention changes the original rotary control head sealing drill tool, which relies on the passive deformation of the sealing core to generate a seal, to a system in which the sealing core is actively squeezed and deformed by a hydraulic cylinder to tighten and hold the square drill rod to generate a seal. The structure of the sealing core is innovatively changed from the traditional conical core to an annular core. The seal is achieved by actively pressurizing the hydraulic device. The activation pressure applied by the hydraulic cylinder can be actively adjusted according to the sealing working pressure requirements, and the hydraulic cylinder pressure can be supplemented and adjusted at any time to ensure a more reliable seal.

[0050] Fourth, based on the characteristics of reverse circulation operations, it can proactively stop the pump to reduce or release annular pressure, ensuring the annulus is pressure-free during long trips in and out of the drill string, thus increasing tripping speed. In special cases, when the square drill pipe joint needs to pass through the sealing assembly, it proactively reduces or releases the cylinder pressure, effectively solving the problem of damage to the sealing core caused by pressurized passage of the square drill pipe joint through the sealing core.

[0051] Example 2 This embodiment provides a specific application and implementation process of an annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations, as detailed below: like Figure 1 As shown, the structure of the annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations includes: a rotating assembly 4, a sealing assembly 13, a drill pipe coupling 9, a clamp 18, a coupling seat 19, and a fixed seat 20; wherein, the rotating assembly 4 includes a first sealing cover 3, a thrust bearing 5, a centering bearing 6, a sealing ring 7, and a second sealing cover 8; the sealing assembly 13 includes a driver 11, a hydraulic cylinder bracket 12, a hydraulic cylinder 14, a sealing core lifting ring 15, and a sealing core 17.

[0052] The aforementioned mounting base 20 is bolted to the blowout preventer 10 (the specifications and quantity of mounting base 20 are selected according to site requirements), and the clamp 18 is fixed to the mounting base 20; the rotating assembly 4 and the sealing assembly 13 are bolted together and fixed to the drill pipe coupling 9 position with the coupling seat 19. During the tripping process, the rotating assembly 4 and the sealing assembly 13 will move up and down relative to the drill pipe 2, but there will be no relative rotation.

[0053] like Figure 2As shown, during the reverse circulation pressure lifting process, the square drill rod 2 is lifted until the drill rod coupling 9 contacts the coupling seat 19. The hydraulic drive clamp 18 is then released. At this time, the rotating assembly 4 and the fixed seat 20 can be freely separated. The square drill rod 2 is lifted, and the rotating assembly 4 and the sealing assembly 13 are lifted by the coupling seat 19 and passed through the turntable 1 for the next operation. At this time, the clamp 18 is fixed on the fixed seat 20.

[0054] like Figure 3 As shown, the rotating assembly 4 includes a first sealing cover 3, a second sealing cover 8, a thrust bearing 5, and a centering bearing 6. The coupling seat 19 is fixed to the second sealing cover 8 with bolts, and its internal dimensions are slightly larger than those of the square drill pipe 2. The thrust bearing 5 mainly prevents abnormal pressure in the wellbore from causing damage to the internal structure of the tool. The centering bearing 6 is used to correct the coaxiality of the square drill pipe 2 and the tool.

[0055] like Figure 4 As shown, the sealing assembly 13 comprises a driver 11, a hydraulic cylinder bracket 12, a sealing core 17, a hydraulic cylinder 14, and a sealing core lifting ring 15. The driver 11 is fixed to the square drill rod 2. The sealing core 17 is an active seal, which is controlled by the hydraulic cylinder 14 to adhere to and separate from the square drill rod 2. The sealing core lifting ring 15 can be easily removed to replace the sealing core 17.

[0056] The following example, pressure-controlled drilling in reverse circulation well workover operations, will be implemented based on the above system components.

[0057] In this embodiment, the specific implementation conditions are as follows: a 4 1 / 2” REG square drill pipe is selected, with a specification of 88.9 and a coupling outer diameter of 139.7mm. A rotary table model ZP275 is selected with an opening diameter of φ698.5mm (27-1 / 2″). The specific implementation steps are as follows: S1. Prepare matching sealing assembly 13, rotating assembly 4, fixing seat 20, bolts, installation tools and other facilities according to the specifications of square drill pipe 2, rotary table model and reverse circulation pressure bearing tool requirements.

[0058] S2. The aforementioned mounting base 20 is fixed to the blowout preventer 10 with bolts (the specifications and quantity of mounting base 20 are selected according to the site requirements) and tightened. The clamp 18 is fixed to the mounting base 20 and tightened.

[0059] S3. Drill down to the bottom of the well normally.

[0060] S4. Connect the square drill rod 2 to the drilling platform. Fix the above-mentioned coupling seat 19 to the upper rotating assembly 4 with bolts. Tighten the rotating assembly 4 to the sealing assembly 13 with bolts. Fix the whole assembly to the square drill rod coupling 9 and tighten it.

[0061] S5. Use an external power source or a manual pressure pump to pressurize the hydraulic cylinder 14 in the sealing assembly 13, causing the hydraulic cylinder 14 to descend, squeezing and deforming the sealing core 17, and clamping the square drill rod 2 to produce a sealing effect.

[0062] S6. After lowering the square drill rod 2 and the rotating assembly 4 into the fixed seat 20, use the hydraulically driven clamp 18 to lock the fixed seat 20 and the rotating assembly 4.

[0063] S7. Start the pump to circulate from the annulus. The square drill rod 2 rotates and drives the driver 11, so that the sealing assembly 13 and the rotating assembly 4 hold the square drill rod 2 and start rotating under pressure. The square drill rod 2 is slowly lowered according to the drilling progress to realize the drilling and grinding operation under pressure.

[0064] S8. After a single drilling operation is completed, stop the pump and depressurize the annulus.

[0065] S9. Lift the square drill pipe 2. The rotating assembly 4 and the sealing assembly 13 move upward under the drive of the coupling seat 19. When the square drill pipe 2 is lifted to the point where the coupling 9 contacts the coupling seat 19 (when it is necessary to maintain the annular constant pressure, the semi-sealed gate blowout preventer can be closed to form a seal on the lower drill pipe 20), control the hydraulic drive to loosen the clamp 18. At this time, the rotating assembly 4 and the fixed seat 19 can be freely separated.

[0066] S10. Remove the square core from the rotary table 1, lift the square drill rod 2 with the sealing assembly 13, and rotate the assembly 4 through the rotary table 1 to perform the single-rod connection operation on the drilling platform.

[0067] S11. After connecting the drill rod 20 to the square drill rod 2, the square drill rod 2 drives the sealing assembly 13 and the rotating assembly 4 to be lowered to the drilling position. At this time, the rotating assembly 4 reaches the position of the fixed seat 19. The clamp 18 can be used to clamp the fixed seat 20 and the rotating assembly 4 again by hydraulic drive. The pump is turned on to restore the annular pressure and the drilling and grinding can begin.

[0068] S12. Repeat the operation to achieve continuous annular pressurized reverse circulation drilling and milling.

[0069] In summary, this invention provides a high-pressure-rated reverse circulation drilling and workover tool and method for annular pressure bearing operations, which has the following advantages compared to existing annular pressure bearing tools: First, this high-pressure reverse circulation drilling and workover tool effectively seals and bears pressure on the annulus of the drill pipe by designing key components such as the sealing assembly, rotating assembly, connectors, and fastening devices, ensuring the safety and stability of drilling and workover operations. The sealing assembly actively seals the annulus and grips the angular drill pipe, effectively preventing leakage of drilling fluid or other media and improving operational efficiency. Second, the rotating assembly, with its thrust bearing and centering bearing, can withstand abnormal axial loads, preventing damage to the annulus pressure-bearing tool itself, while ensuring the coaxiality of the tool and the angular drill pipe, improving operational accuracy and reliability. Furthermore, the rotating assembly's design facilitates connection and fixation with the sealing assembly and connectors, making the overall tool structure more compact and rational. Finally, the connectors employ a fixed base and a multi-segment split structure, along with a cavity design that mates with the bottom of the rotating assembly, resulting in a more robust and stable connection. Meanwhile, the use of fastening devices such as clamps enables rapid fixing and separation between the rotating assembly and the connecting parts, facilitating the replacement and connection of angular drill pipes during operations. Furthermore, this invention provides detailed usage methods, including sealing and unsealing steps, drill pipe connection operations, etc., allowing operators to use this annular pressure-bearing tool for drilling and well workover operations more conveniently and quickly. Simultaneously, pressurizing the hydraulic cylinder in the sealing assembly via an external power source or manual pressure pump achieves the deformation of the sealing core and the clamping action of the angular drill pipe, making operation simple and reliable. This invention also considers the replacement of the sealing core; it can be replaced by pulling the sealing core lifting ring at the top, facilitating tool maintenance and upkeep for operators. Therefore, this invention improves the safety and stability of drilling and well workover operations while also increasing operational efficiency and accuracy, reducing operating costs and maintenance difficulty, and possesses high practical value and promotional significance.

[0070] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A high-pressure reverse circulation drilling and workover tool for annular pressure bearing, characterized in that, Includes a sealing assembly (13), a rotating assembly (4), connectors, and fastening devices; The sealing assembly (13) is sleeved on the square drill rod (2) and is used to actively seal the annulus of the square drill rod (2) so that the sealing assembly (13) can hold the square drill rod (2). The rotating assembly (4) is connected below the sealing assembly (13) and sleeved on the square drill rod (2). The rotating assembly (4) is used to bear abnormal axial loads to prevent damage to the annular pressure bearing tool and to make the annular pressure bearing tool coaxial with the square drill rod (2). One end of the connector is connected to the rotating assembly (4) via a fastening device, and the other end is connected to the blowout preventer (10).

2. The annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations according to claim 1, characterized in that, The sealing assembly (13) includes a sealing assembly housing, which is sleeved on the square drill rod (2) and has a driver (11), a hydraulic cylinder bracket (12), a hydraulic cylinder (14) and a sealing core (17) inside. The hydraulic cylinder bracket (12) is fixed on the inner wall of the sealing assembly housing, and the hydraulic cylinder (14) is fixed on the hydraulic cylinder bracket (12) and connected to the output end of the driver (11); The sealing core (17) is arranged circumferentially along the square drill rod (2) and located within the annulus of the square drill rod (2); The hydraulic cylinder (14) can deform the sealing core (17) under the action of the driver (11) to actively seal the annulus of the square drill rod (2), so that the sealing assembly (13) holds the square drill rod (2). The bottom of the sealing assembly housing is bolted to the rotating assembly (4).

3. The annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations according to claim 2, characterized in that, The top of the sealing core (17) is connected to a sealing core lifting ring (15).

4. The annular pressure-bearing tool for high-pressure reverse circulation drilling and workover operations according to claim 1, characterized in that, The rotary assembly (4) includes a rotary assembly housing fitted onto the square drill rod (2), and the rotary assembly housing is provided with a thrust bearing (5) and a centering bearing (6) that cooperate with the square drill rod (2). The thrust bearing (5) is used to withstand abnormal axial loads to prevent damage to the annular bearing tool. The centering bearing (6) is used to ensure the coaxiality of the annular pressure bearing tool and the square drill rod (2).

5. The high-pressure reverse circulation drilling and workover tool according to claim 4, characterized in that, The top of the rotating assembly housing is provided with a first sealing cover (3) and a second sealing cover (8). The top of the first sealing cover (3) is connected to the bottom of the sealing assembly (13); the bottom of the second sealing cover (8) is connected to a coupling seat (19), which is used to support the rotating assembly (4). The coupling seat (19) is connected to the connector by a fastening device.

6. The high-pressure reverse circulation drilling and workover tool according to any one of claims 1-5, characterized in that, The connector adopts a fixed seat (20), which has a multi-segment split structure. The uppermost segment is provided with a cavity that matches the bottom of the rotating assembly (4), and the lowermost segment is bolted to the blowout preventer (10).

7. The high-pressure reverse circulation drilling and workover tool according to claim 6, characterized in that, The fastening device uses a clamp (18), which is fitted onto the uppermost part of the fixed seat (20). The clamp (18) includes two annular clamps that can clamp and open under hydraulic pressure to achieve the fixation and separation between the rotating assembly (4) and the fixed seat (20).

8. A method for using a high-pressure reverse circulation drilling and workover tool for annular pressure bearing operations, characterized in that... Based on the high-pressure reverse circulation drilling and workover tool according to any one of claims 1-7, it comprises: After the sealing assembly (13) and the rotating assembly (4) are lowered to the connecting part position along with the square drill rod (2), the rotating assembly (4) is fixed to the connecting part using a fastening device; The sealing assembly (13) is used to actively seal the annulus of the square drill rod (2), so that the sealing assembly (13) can hold the square drill rod (2) tightly and perform pressurized drilling and grinding operations. After a single drill bit is drilled, the sealing assembly (13) releases the seal from the annulus of the drill rod (2) and separates the rotating assembly (4) from the connecting part by means of a fastening device; Raise the square drill rod (2) and perform the drill rod connection operation; After the drill rod connection operation is completed, the square drill rod (2) is lowered again for subsequent operations.

9. The method of using the high-pressure reverse circulation drilling and workover tool according to claim 8, characterized in that, An external power source or a manual pressure pump is used to pressurize the hydraulic cylinder (14) in the sealing assembly (13), causing the hydraulic cylinder (14) to descend, squeezing the sealing core (17) to deform and clamp the square drill rod (2), thus producing a sealing effect.

10. The method of using the high-pressure reverse circulation drilling and workover tool according to claim 8, characterized in that, During the drill pipe connection operation, the sealing core lifting ring (15) at the top of the sealing core (17) is pulled up to replace the sealing core (17).

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