A method of using a high build rate drilling assembly

Abstract

The present application belongs to the technical field of oilfield drilling engineering, and particularly relates to a use method of a high build-up rate drilling tool assembly device, comprising the following steps: S1, selecting a suitable drill bit and a single-bend screw rod matched with the drill bit according to drilling requirements, and designing a centralizer with a determined centralizing direction; S2, mounting the drill bit and the centralizer on two ends of the single-bend screw rod respectively to complete preliminary assembly of the drilling tool; S3, adjusting the bending direction of the single-bend screw rod to be consistent with the centralizing direction of the centralizer, and then fixing the centralizer relative to the single-bend screw rod to complete assembly of the drilling tool; and S4, performing composite drilling operation and sliding drilling operation by using the assembled drilling tool according to the design requirements of drilling construction. The technical scheme can push out the centralizing blocks in the high-edge direction of the variable-diameter centralizer through liquid force in the process of sliding drilling, apply force to the well wall, take the single-bend point of the screw rod as a fulcrum, and apply a lateral force to the high edge of the drill bit, so that the build-up capacity is increased.

Description

Technical Field

[0001] This invention belongs to the field of oilfield drilling engineering technology, specifically relating to a method for using a high build-up rate drilling tool assembly. Background Technology

[0002] With the proliferation of horizontal wells, directional wells, and branched horizontal wells, especially large-diameter horizontal wells, ensuring build-up efficiency during drilling operations has become increasingly difficult. During drilling, the configuration of directional drilling tools, their structural shape, drilling process parameters, and formation geological parameters all influence the build-up rate, with the directional drilling tool assembly having the greatest impact. High build-up rate drilling tool assemblies can reduce the slip ratio during directional drilling and increase the rate of penetration, which is of great significance for further promoting efficient composite directional drilling technology.

[0003] The term "large borehole" refers to a wellbore with a diameter greater than 241mm, generally including diameters such as φ311mm, φ346mm, φ394mm, and φ444.5mm. Many problems often arise during the construction of large boreholes. For exploration horizontal wells, to account for the uncertainties of exploration operations and ensure safe and smooth exploration, a large three-section wellbore structure is generally adopted, with a reserved layer of technical casing. For example, the gas exploration horizontal wells in Changqing Oilfield generally adopt a wellbore structure of φ444.5mm drill bit × φ339.7mm surface casing + φ311.2mm drill bit × φ244.5mm technical casing + φ215.9mm drill bit × φ139.7mm production casing. In deviated sections, a 311.2mm drill bit is used. The large borehole size in deviated sections results in low directional drilling efficiency with large-diameter screw drills, and directional drilling in deviated sections suffers from pressure build-up, tool face instability, and low mechanical drilling rates. Especially in the early stages of deviated well sections, the sliding ratio needs to reach over 80% for sections with an inclination of 0-30 degrees and over 50% for sections with an inclination of 30-60 degrees to meet trajectory control requirements. In the Changqing Oilfield gas exploration horizontal wells with a large φ311.2mm borehole size and low screw drill build-up rate, it is crucial to prevent under-inclination from causing passive trajectory control. Based on actual drilling data analysis, the PDC build-up rate is low in the small-inclination section of the φ311.2mm borehole, especially due to difficulties in initiating inclination at the build-up point, easily leading to under-inclination. This is typically addressed by changing the drill bit, increasing the angle of the single-bend screw drill, and increasing the length of the sliding section, sacrificing mechanical drilling rate to complete the large-inclination borehole build-up.

[0004] For bottom screw drill string assemblies with the same screw bend angle under different wellbore conditions, for example, the build-up rate of the bottom screw drill string assembly in the build-up section of a well with a diameter of φ444.5mm is lower than that of the bottom screw drill string assembly in the build-up section of a well with a diameter of φ311.2mm, especially in the initial build-up section. Improving the build-up rate of large-diameter wells and increasing the ratio of composite drilling to sliding drilling, thereby significantly increasing the drilling rig speed, is of great significance to drilling operations. Summary of the Invention

[0005] The purpose of this invention is to propose a method for using a high build-up rate drill bit assembly device. A diameter-adjusting stabilizer is installed on the drill bit. During sliding drilling, the stabilizer block in the high side direction of the diameter-adjusting stabilizer is pushed out by hydraulic force, exerting force on the well wall. The single bend point of the screw is used as the force point to apply a lateral force to the high side of the drill bit, thereby increasing the build-up rate.

[0006] This invention is achieved by adopting the following technical solution:

[0007] A method of using a high build-up rate drill string assembly, characterized by comprising the following steps:

[0008] S1. Prepare the drill string assembly, including selecting the appropriate drill bit and a single-bend screw that matches the drill bit according to the drilling requirements, and designing a stabilizer that determines the direction of the stabilizer.

[0009] S2, Assemble the drilling tools. Install the drill bit and stabilizer at both ends of the single-bend screw, so that the interior of the stabilizer, single-bend screw and drill bit are sealed and connected in sequence, thus completing the initial assembly of the drilling tools.

[0010] S3. Adjust the drill bit posture. After aligning the bending direction of the single-bend screw with the straightening direction of the stabilizer, fix the stabilizer and the single-bend screw relative to each other using the connecting lock to complete the drill bit assembly.

[0011] S4. According to the drilling construction design requirements, the assembled drilling tools are used to carry out composite drilling and sliding drilling operations. In the composite drilling state, the drilling tools rotate as a whole under the control of the surface equipment, while the single-bend screw drives the drill bit to rotate under the action of the internal fluid. When it is necessary to create an directional deviation, the drilling tools stop rotating as a whole, and the single-bend screw drives the drill bit to rotate under the action of the internal fluid. At the same time, the stabilizer works with the single-bend screw to create an directional deviation in the target direction.

[0012] Preferably, in step S1, the straightener is a variable diameter deflection straightener, including a straightening rod, a deflection variable diameter channel is provided through the straightening rod along its axial direction, a pressure relief mechanism and several straightening units are provided on the side of the straightening rod; a bypass channel is provided inside the straightening rod, one end of the bypass channel is connected to the deflection variable diameter channel, and the other end of the bypass channel is connected to the pressure relief mechanism.

[0013] Preferably, in step S1, the straightening unit includes an installation groove, a sliding sleeve, and a straightening block; the installation groove is radially opened along the straightening rod, the sliding sleeve is fixedly installed in the installation groove and tightly fits against the groove wall; the straightening block is located inside the sliding sleeve, sealingly fits against the inner wall of the sliding sleeve, and is slidably connected to the sliding sleeve for limiting.

[0014] Preferably, in step S4, the directional tilting in the target direction using a stabilizer and a single-bend screw includes the following steps:

[0015] Adjust the drilling face posture according to the target direction to prepare for directional operation;

[0016] Hydraulic force is injected into the drill string through surface equipment (such as by pumping high-pressure drilling fluid into the drill fluid pump), causing the centralizer's centralizing blocks to extend radially under hydraulic pressure until they support the well wall;

[0017] The supporting force of the straightening block on the well wall is F1, and the well wall provides the straightening block with a supporting force F2 in the same and opposite direction.

[0018] Under the action of the counter-support force F2, the bending support point of the single-bend screw is used as the point of force application, so that a force F3 is generated at the high force point of the drill bit, and then the sliding drilling operation begins.

[0019] Preferably, in step S1, the biased variable diameter channel includes an inlet connector, a first variable diameter channel, an eccentric variable diameter channel and a second variable diameter channel that are axially connected in sequence, and the flow area of ​​the eccentric variable diameter channel is less than the flow area of ​​the first variable diameter channel and less than the flow area of ​​the second variable diameter channel.

[0020] Preferably, in step S1, the pressure relief mechanism includes a bypass valve body and a pressure relief groove radially opened on the side of the straightening rod, the bottom of the pressure relief groove being connected to the first diameter changing channel; one end of the bypass channel being connected to the pressure relief groove, and the other end being connected to the second diameter changing channel; the bypass valve body is embedded in the pressure relief groove and is used to control the bypass channel to be connected to and closed with the first diameter changing channel.

[0021] Preferably, the connection locking device includes a connection locking sleeve, a connector female buckle for connecting the straightening rod, and a connection male buckle for connecting the screw; the connection male buckle and the connection female buckle are fastened together by the connection locking sleeve.

[0022] Preferably, in step S1, the bending angle of the single-bend screw is 0.5°, 0.75°, 1°, 1.24°, 1.5°, 1.75° or 2°.

[0023] The beneficial technical effects of this invention are as follows:

[0024] This technical solution proposes a method for using a high build-up rate drilling tool assembly. By combining a centralizer, a single-bend screw, and a drill bit, this assembly structure can be used to perform both sliding drilling and combined drilling operations during well drilling. With the assistance of the centralizer, stable directional build-up is achieved during sliding drilling operations. Based on this method, in actual drilling projects, the sliding build-up rate can be increased, the sliding well section can be reduced, and drilling efficiency can be improved.

[0025] This technical solution proposes a method for using a high build-up rate drilling tool assembly. By combining a specially designed centralizer with a single-bend screw and drill bit, downhole directional drilling can be controlled from the surface. Specifically, a deflection and variable diameter channel is designed inside the centralizer to apply hydraulic pressure. Since existing drilling operations require the injection of fluid into the drilling tools, the structure and working principle of this centralizer are compatible with existing drilling technology, allowing it to be integrated into existing drilling equipment and technology. The structure is ingeniously designed and easy to operate. Attached Figure Description

[0026] Figure 1 This is a basic implementation flowchart of the technical solution;

[0027] Figure 2 Structural schematic diagram for implementing this technical solution;

[0028] Figure 3 This is a schematic diagram of the axial cross-sectional structure of the centralizer;

[0029] Figure 4 This is a schematic diagram of the axial cross-sectional structure of the connecting lock.

[0030] In the picture:

[0031] 1. Drill bit; 2. Single-bend screw; 3. Bending support point; 4. Centralizer; 4.1. Centralizer rod; 4.2. Pressure relief mechanism; 4.21. Bypass channel; 4.22. Pressure relief groove; 4.23. Connector; 4.24. Spring; 4.25. Sealing ball; 4.3. Centralizer unit; 4.31. Mounting groove; 4.32. Sliding sleeve; 4.33. Centralizer block; 4.4. Liquid inlet connector; 4.5. First diameter changing channel; 4.6. Eccentric diameter changing channel; 4.7. Second diameter changing channel; 5. Connecting lock; 5.1. Connecting locking sleeve; 5.2. Connector female thread; 5.3. Connecting male thread; 6. Fluid flow direction. Detailed Implementation

[0032] To make the purpose, technical solution and advantages of the invention clearer, the technical solution of the invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the invention, but not all embodiments.

[0033] Therefore, the following detailed description 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.

[0034] Example 1

[0035] This embodiment discloses a method for using a high build-up rate drilling tool assembly. As a basic implementation of the present invention, the high build-up rate drilling tool assembly includes a drill bit 1, a single-bend screw 2, and a stabilizer 4, etc. Further, this technical solution uses a single-bend screw 2 with a bending angle of 0.5°, 0.75°, 1°, 1.24°, 1.5°, 1.75°, or 2°. Based on this, the method includes the following steps:

[0036] S1, Prepare the drill string assembly, including selecting a suitable drill bit 1 and a single-bend screw 2 that is compatible with the drill bit 1 according to the drilling requirements, and design a stabilizer 4 that determines the direction of the stabilizer.

[0037] S2, Assemble the drilling tools. Install the drill bit 1 and the stabilizer 4 at both ends of the single-bend screw 2 respectively, so that the interiors of the stabilizer 4, the single-bend screw 2 and the drill bit 1 are sealed and connected in sequence, thus completing the initial assembly of the drilling tools.

[0038] S3, adjust the drill bit posture, and after adjusting the bending direction of the single-bend screw 2 to be consistent with the straightening direction of the stabilizer 4, fix the stabilizer 4 and the single-bend screw 2 relative to each other through the connecting lock 5 to complete the drill bit assembly;

[0039] S4. According to the drilling construction design requirements, the assembled drilling tools are used to carry out composite drilling and sliding drilling operations. In the composite drilling state, the drilling tools rotate as a whole under the control of the surface equipment, while the single-bend screw 2 drives the drill bit 1 to rotate under the action of the internal fluid (drilling fluid). When it is necessary to create an directional drilling direction, the drilling tools stop rotating as a whole, and the single-bend screw 2 drives the drill bit 1 to rotate under the action of the internal fluid (drilling fluid). At the same time, the stabilizer 4 cooperates with the single-bend screw 2 to create an directional drilling direction in the target direction.

[0040] In actual construction sites, as the drilling depth increases, drill collars, rotary table, drill pipe, and other downhole tools are connected to the rear of the stabilizer 4. The connection and application of these drilling devices are standard practice in this field and will not be elaborated upon here. Conventional directional drilling is divided into sliding drilling and combined drilling depending on the drilling method. In sliding drilling, the rotary table is locked (which can be understood as "cutting off" the overall rotational control of the drill collars, stabilizer 4, single-bend screw 2, and drill bit 1 from the surface rotary drive equipment), and only the single-bend screw 2 drives the drill bit 1 to rotate to cut the formation. In sliding drilling, directional drilling operations can be performed with the help of the stabilizer 4. In the combined drilling state, screw drilling (i.e., the single-bend screw 2 drives the drill bit 1 to rotate) and rotary table drilling (i.e., the rotary table is unlocked, and the ground rotation drive equipment controls the overall synchronous rotation of the drill collar, stabilizer 4, single-bend screw 2 and drill bit 1, etc.) are combined. At this time, the bending direction of the single-bend screw 2 is uncertain, so it is impossible to create an skew.

[0041] Example 2

[0042] This embodiment discloses a method for using a high build-up rate drilling tool assembly. As a basic implementation of the present invention, the high build-up rate drilling tool assembly includes a drill bit 1, a single-bend screw 2, and a stabilizer 4, etc. Based on this, the method includes the following steps:

[0043] S1. Prepare the drill string assembly, including selecting a suitable drill bit 1 according to drilling requirements and a single-bend screw 2 adapted to the drill bit 1, and designing a stabilizer 4 with a defined stabilizer direction. The stabilizer 4 is a variable-diameter deflection stabilizer 4, including a stabilizer rod 4.1, with a deflection variable-diameter channel extending through the stabilizer rod 4.1 axially. A pressure relief mechanism 4.2 and several stabilizer units 4.3 are provided on the side of the stabilizer rod 4.1. A bypass channel 4.21 is opened inside the stabilizer rod 4.1, one end of which connects to the deflection variable-diameter channel, and the other end of which connects to the pressure relief mechanism 4.2.

[0044] S2, Assemble the drilling tools. Install the drill bit 1 and the stabilizer 4 at both ends of the single-bend screw 2 respectively, so that the interiors of the stabilizer 4, the single-bend screw 2 and the drill bit 1 are sealed and connected in sequence, thus completing the initial assembly of the drilling tools.

[0045] S3. Adjust the drill bit posture. After aligning the bending direction of the single-bend screw 2 with the straightening direction of the stabilizer 4, fix the stabilizer 4 and the single-bend screw 2 relative to each other using the connecting lock 5 to complete the drill bit assembly.

[0046] S4. According to the drilling construction design requirements, the assembled drilling tools are used to carry out composite drilling and sliding drilling operations. In the composite drilling state, the drilling tools rotate as a whole under the control of the surface equipment, while the single-bend screw 2 drives the drill bit 1 to rotate under the action of the internal fluid (drilling fluid). When it is necessary to create an directional drilling direction, the drilling tools stop rotating as a whole, and the single-bend screw 2 drives the drill bit 1 to rotate under the action of the internal fluid (drilling fluid). At the same time, the stabilizer 4 cooperates with the single-bend screw 2 to create an directional drilling direction in the target direction.

[0047] Example 3

[0048] This embodiment discloses a method for using a high build-up rate drilling tool assembly. As a basic implementation of the present invention, the high build-up rate drilling tool assembly includes a drill bit 1, a single-bend screw 2, and a stabilizer 4, etc. Based on this, the method includes the following steps:

[0049] S1. Prepare the drill string assembly, including selecting a suitable drill bit 1 according to drilling requirements and a single-bend screw 2 adapted to the drill bit 1, and designing a stabilizer 4 with a defined stabilizer direction. The stabilizer 4 is a variable-diameter deflection stabilizer 4, including a stabilizer rod 4.1, with a deflection variable-diameter channel extending through the stabilizer rod 4.1 axially. A pressure relief mechanism 4.2 and several stabilizer units 4.3 are provided on the side of the stabilizer rod 4.1. A bypass channel 4.21 is opened inside the stabilizer rod 4.1, one end of which connects to the deflection variable-diameter channel, and the other end of which connects to the pressure relief mechanism 4.2. The straightening unit 4.3 includes a mounting groove 4.31, a sliding sleeve 4.32, and a straightening block 4.33. The mounting groove 4.31 is radially opened along the straightening rod 4.1. The sliding sleeve 4.32 is fixedly installed in the mounting groove 4.31 and is tightly fitted with the groove wall of the mounting groove 4.31. The straightening block 4.33 is located inside the sliding sleeve 4.32, is sealed and fitted with the inner wall of the sliding sleeve 4.32, and is limited and slidably connected with the sliding sleeve 4.32.

[0050] S2, Assemble the drilling tools. Install the drill bit 1 and the stabilizer 4 at both ends of the single-bend screw 2 respectively, so that the interiors of the stabilizer 4, the single-bend screw 2 and the drill bit 1 are sealed and connected in sequence, thus completing the initial assembly of the drilling tools.

[0051] S3. Adjust the drill bit posture, aligning the bending direction of the single-bend screw 2 with the straightening direction of the stabilizer 4. Then, use the connecting locking device 5 to fix the stabilizer 4 and the single-bend screw 2 relative to each other, completing the drill bit assembly. The connecting locking device 5 includes a connecting locking sleeve 5.1, a female connector 5.2 for connecting the stabilizer 4.1, and a male connector 5.3 for connecting the screw; the male connector 5.3 and the female connector are securely connected via the connecting locking sleeve 5.1.

[0052] S4. According to the drilling construction design requirements, composite drilling and sliding drilling operations are performed using the assembled drill string. In composite drilling, the drill string rotates as a whole under the control of the surface equipment, while the single-bend screw 2 drives the drill bit 1 to rotate under the action of the internal fluid (drilling fluid). When directional drilling is required, the system enters sliding drilling mode, where the drill string stops rotating as a whole, and the single-bend screw 2 continues to drive the drill bit 1 to rotate under the action of the internal fluid (drilling fluid). Simultaneously, the stabilizer 4, in conjunction with the single-bend screw 2, guides the drill string towards the target direction for directional drilling. The directional drilling process using the stabilizer 4 and the single-bend screw 2 includes the following steps:

[0053] Adjust the drilling face posture according to the target direction to prepare for directional operation;

[0054] Hydraulic force is injected into the drill string through ground equipment, causing the centralizer 4's centralizing block 4.33 to extend radially under hydraulic operation until it supports the well wall;

[0055] The supporting force of the straightening block 4.33 on the well wall is F1, and the well wall provides the straightening block 4.33 with a supporting force F2 in the same and opposite direction, F1=F2;

[0056] Under the action of the counter-support force F2, the bending support point 3 of the single-bend screw 2 is used as the point of force exertion, so that a force F3 is generated at the high force point of the drill bit 1, and then the sliding drilling operation begins.

[0057] Furthermore, once the sliding drilling operation is completed (i.e., the current directional drilling task is completed), the drill string is switched to the composite drilling state. Specifically, the switch can be completed by unlocking the rotary table. After the switch, the centralizer 4's centralizing block 4.33 retracts into the centralizing rod 4.1 under the action of rotational force to withdraw the supporting force on the well wall.

[0058] Example 4

[0059] This embodiment discloses a method for using a high build-up rate drilling tool assembly. As a basic implementation of the present invention, the high build-up rate drilling tool assembly includes a drill bit 1, a single-bend screw 2, and a stabilizer 4. The stabilizer 4 is a variable-diameter deflection stabilizer 4, including a stabilizer rod 4.1, with a deflection variable-diameter channel extending through the stabilizer rod 4.1 axially. A pressure relief mechanism 4.2 and several stabilizer units 4.3 are provided on the side of the stabilizer rod 4.1. A bypass channel 4.21 is provided inside the stabilizer rod 4.1, with one end of the bypass channel 4.21 connected to the deflection variable-diameter channel and the other end connected to the pressure relief mechanism 4.2. Based on the above structure, the working principle of the aforementioned reducer is as follows: The deflection channel has the function of regulating pressure. Specifically, when the drill string is in a combined drilling state, the pressure relief mechanism 4.2 is closed, and the injected fluid (drilling fluid) is controlled by surface equipment (such as a drilling fluid pump). Under the action of the fluid deflecting towards the reducer channel, its hydraulic force increases at a local position in the deflection channel, thereby controlling the centering unit 4.3 to perform support work. When switching to the combined drilling state, the pressure relief mechanism 4.2 is opened, and the hydraulic force at a local position in the deflection channel is reduced by depressurization, causing the centering unit 4.3 to retract its support action.

[0060] Furthermore, the centralizing unit 4.3 includes an installation groove 4.31, a sliding sleeve 4.32, and a centralizing block 4.33. The installation groove 4.31 is radially opened along the centralizing rod 4.1. The sliding sleeve 4.32 is fixedly installed in the installation groove 4.31 and tightly fits against the groove wall of the installation groove 4.31. The centralizing block 4.33 is located inside the sliding sleeve 4.32, sealingly fitting against the inner wall of the sliding sleeve 4.32, and is limited and slidably connected to the sliding sleeve 4.32. Based on this structure, the working principle of the centralizing unit 4.3 is as follows: When the hydraulic force at the corresponding local position in the variable diameter channel increases, the centralizing block 4.33 extends radially outward under the action of the hydraulic force to support the well wall. A mutual supporting force is generated between the centralizer 4 and the well wall. After the pressure is released through the pressure relief mechanism 4.2, the hydraulic force decreases, the centralizing block 4.33 retracts radially, and the supporting force is withdrawn.

[0061] Furthermore, the deflection-variable-diameter channel includes, sequentially axially connected inlet connector 4.4, first variable-diameter channel 4.5, eccentric variable-diameter channel 4.6, and second variable-diameter channel 4.7 (the second variable-diameter channel 4.7 is also an outlet channel, with an outlet connector installed on the outer wall of the centralizing rod at its location). The flow area of ​​the eccentric variable-diameter channel 4.6 < the flow area of ​​the first variable-diameter channel 4.5 ≤ the flow area of ​​the second variable-diameter channel 4.7. Based on this structure, since the flow areas of each channel are different, the hydraulic pressure in each channel is also different. Because the flow areas of the eccentric variable-diameter channels 4.6 and 4.7 decrease sequentially, the hydraulic pressure can be controlled by controlling the flow rate of the injected fluid (drilling fluid) through surface equipment (such as a drilling fluid pump). Furthermore, based on this deflection-variable-diameter channel structure, to achieve the utilization and control of hydraulic pressure, it is best to position the pressure relief mechanism 4.2 and the centralizing unit 4.3 at the corresponding positions of the first variable-diameter channel 4.5.

[0062] Furthermore, the pressure relief mechanism 4.2 includes a bypass valve body and a pressure relief groove 4.22 radially opened on the side of the stabilizer 4.1. The bottom of the pressure relief groove 4.22 is connected to the first variable diameter channel 4.5. One end of the bypass channel 4.21 is connected to the pressure relief groove 4.22, and the other end is connected to the second variable diameter channel 4.7. The bypass valve body is embedded in the pressure relief groove 4.22 and is used to control the connection and closure of the bypass channel 4.21 and the first variable diameter channel 4.5. Based on this structure, when the drill bit is in the sliding drilling state, the bypass valve body is in the closed state, ensuring that the hydraulic pressure in the first variable diameter channel 4.5 increases. When the drill bit is in the combined drilling state, due to the rotation of the stabilizer 4, the bypass valve body opens under the action of centrifugal force, and part of the fluid in the first variable diameter channel 4.5 flows directly into the second variable diameter channel 4.7 through the bypass channel 4.21 to achieve the purpose of pressure relief.

[0063] Furthermore, based on the aforementioned working requirements of the bypass valve body, the bypass valve body can adopt the following structure: the bypass valve body includes a connecting body 4.23, a spring 4.24, and a sealing ball 4.25; the connecting body 4.23 is fixedly connected to the centralizing rod 4.1, and the two ends of the spring 4.24 are respectively connected to the sealing ball 4.25 and the connecting body 4.23. Thus, when the drill bit is in the sliding drilling state, the sealing ball 4.25, under the action of the spring 4.24, blocks the pressure relief groove 4.22 and the first diameter changing channel 4.5. When the drill bit is in the combined drilling state, the sealing ball 4.25, under the action of centrifugal force, leaves its original blocking position and compresses the spring 4.24. At this time, the first diameter changing channel 4.5, the pressure relief groove 4.22, and the bypass channel 4.21 are sequentially connected.

Claims

1. A method of using a high build-up rate drill string assembly, characterized in that... Includes the following steps: S1, Prepare the drill string assembly, including selecting a suitable drill bit (1) according to the drilling requirements and a single-bend screw (2) that matches the drill bit (1), and design a stabilizer (4) that determines the stabilizing direction, wherein: The straightener (4) includes a straightening rod (4.1), and a deflection variable diameter channel is provided through the straightening rod (4.1) along its axial direction; a pressure relief mechanism (4.2) and several straightening units (4.3) are provided on the side of the straightening rod (4.1), and a bypass channel (4.21) is provided. The biased variable diameter channel includes an inlet connector (4.4), a first variable diameter channel (4.5), an eccentric variable diameter channel (4.6), and a second variable diameter channel (4.7) connected axially in sequence, and the flow area of ​​the eccentric variable diameter channel (4.6) is less than the flow area of ​​the first variable diameter channel (4.5) and less than the flow area of ​​the second variable diameter channel (4.7). The pressure relief mechanism (4.2) includes a bypass valve body and a pressure relief groove (4.22) radially opened along the straightening rod (4.1); the bottom of the pressure relief groove (4.22) is connected to the first diameter change channel (4.5) of the deflection diameter change channel; one end of the bypass channel (4.21) is connected to the pressure relief groove (4.22), and the other end is connected to the second diameter change channel (4.7) of the deflection diameter change channel; the bypass valve body is embedded in the pressure relief groove (4.22) and is used to control the connection and closure of the bypass channel (4.21) and the first diameter change channel (4.5); The straightening unit (4.3) is located on the outside of the first variable diameter channel (4.5) and achieves radial expansion and contraction based on the magnitude of the hydraulic force inside the first variable diameter channel (4.5); S2, Assemble the drilling tools. Install the drill bit (1) and the stabilizer (4) at both ends of the single-bend screw (2) respectively, so that the interior of the stabilizer (4), the single-bend screw (2) and the drill bit (1) are sealed and connected in sequence, and the initial assembly of the drilling tools is completed. S3, adjust the attitude of the drill bit, and after adjusting the bending direction of the single-bend screw (2) to be consistent with the straightening direction of the stabilizer (4), fix the stabilizer (4) and the single-bend screw (2) relative to each other by connecting the locking device (5) to complete the assembly of the drill bit; S4, according to the drilling construction design requirements, utilizes the assembled drilling tools to perform composite drilling operations and sliding drilling operations; among which: In the combined drilling state, the drill bit rotates as a whole under the control of the ground equipment, while the single-bend screw (2) drives the drill bit (1) to rotate under the action of the internal fluid; When it is necessary to create an directional drilling direction, the drill string switches to the sliding drilling state, the drill string stops rotating as a whole, and the single-bend screw (2) continues to drive the drill bit (1) to rotate under the action of the internal fluid. The stabilizer (4) works with the single-bend screw (2) to create an directional drilling direction in the target direction.

2. The method of using the high build-up rate drill string assembly as described in claim 1, characterized in that: In step S1, the straightening unit (4.3) includes an installation groove (4.31), a sliding sleeve (4.32), and a straightening block (4.33). The installation groove (4.31) is radially opened along the straightening rod (4.1). The sliding sleeve (4.32) is fixedly installed in the installation groove (4.31) and is tightly fitted with the groove wall of the installation groove (4.31). The straightening block (4.33) is located inside the sliding sleeve (4.32), is sealed and fitted with the inner wall of the sliding sleeve (4.32), and is limited and slidably connected with the sliding sleeve (4.32).

3. The method of using the high build-up rate drill string assembly as described in claim 2, characterized in that: In step S4, the directional tilting in the target direction by using the straightener (4) in conjunction with the single-bend screw (2) includes the following steps: Adjust the drilling face posture according to the target direction to prepare for directional operation; The bypass valve body remains closed, and drilling fluid is injected into the drill string through the surface equipment. Based on the deflection channel, the variable diameter structure establishes hydraulic force in its first variable diameter channel (4.5), so that the centralizer (4) centralizing block (4.33) extends radially under the operation of hydraulic force until it supports the well wall. The supporting force of the straightening block (4.33) on the well wall is F1, and the well wall provides the straightening block (4.33) with a supporting force F2 in the same and opposite direction. Under the action of the counter-support force F2, the bending support point (3) of the single-bend screw (2) is used as the point of force, so that a force F3 is generated at the high force point of the drill bit (1), and then the sliding drilling operation begins.

4. The method of using the high build-up rate drill string assembly as described in claim 1, characterized in that: The connecting lock (5) includes a connecting locking sleeve (5.1), a female connector (5.2) for connecting the straightening rod (4.1), and a male connector (5.3) for connecting the screw; the male connector (5.3) and the female connector are fastened together by the connecting locking sleeve (5.1).

5. The method of using the high build-up rate drill string assembly as described in claim 1, characterized in that: In step S1, the bending angle of the single-bend screw (2) is 0.5°, 0.75°, 1°, 1.24°, 1.5°, 1.75° or 2°.

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