A rotating sand cleaning anti-holding pressure drilling tool assembly for drilling a well and a method of use

Abstract

The application provides a rotary sand cleaning anti-holding pressure drilling tool combination and a use method, and belongs to the technical field of drilling engineering. The drilling tool combination comprises a drill bit, an anti-holding pressure short section, a non-centralizing screw rod and a flexible short section, the drill bit, the anti-holding pressure short section, the non-centralizing screw rod and the flexible short section are sequentially connected from bottom to top, and the upper end of the flexible short section is provided with a back pressure valve. The centralizer on the single-bend single-centralizing screw rod body is replaced by the independent anti-holding pressure short section between the PDC drill bit and the non-centralizing screw rod, the movement state of the anti-holding pressure short section during sliding drilling is changed, the sliding advancement is changed into rotary advancement, the axial frictional resistance is reduced, the wellbore purification effect near the well bottom is improved, the sliding dragging pressure problem is fundamentally solved, and the directional drilling construction efficiency is greatly increased.

Description

Technical Field

[0001] This invention belongs to the field of drilling engineering technology, specifically relating to a rotary sand-cleaning and anti-pressure drilling tool assembly and its usage method. Background Technology

[0002] With the increasing efforts to reduce costs and improve efficiency in the oil drilling industry in recent years, the demand for faster drilling has become increasingly urgent. However, the biggest constraint on speed improvement, the problem of sliding drag, has not only failed to be effectively solved, but has become even more prominent with the widespread application of drilling fluid without ground contact. To alleviate sliding drag, the common practice is to use salt-cement mud, increasing the salt content, reducing the solid content, and increasing the lubricant content. This significantly increases mud costs and is also difficult to achieve the desired anti-drag effect.

[0003] Publication No. CN104912487B discloses a drill string anti-pressure device for directional wells, comprising: a mandrel, the mandrel being a cavity with a through hole; a mandrel sleeve, the mandrel sleeve being axially movable and fitted onto the outside of the mandrel; high-pressure mud flowing through the inner cavity of the mandrel sleeve and through the inner cavity of the mandrel; a flow-stopping piston provided at the inlet end of the mandrel, the flow-stopping piston being able to transfer part of the pressure of the high-pressure mud to the mandrel, while ensuring unobstructed flow of the high-pressure mud; and an impeller, the impeller being disposed inside the mandrel, the axis of rotation of the impeller being perpendicular to the axial direction of the mandrel, the high-pressure mud driving the impeller to rotate. This invention's drill string anti-pressure device for directional wells, by setting an impeller and a flow-stopping piston within the high-pressure mud flow channel, causes the mandrel to generate axial pulse vibration, reducing friction between the drill string and the wellbore, solving the pressure problem, and improving drilling efficiency.

[0004] Currently, publicly disclosed patents on anti-slip pressure drill string assemblies mainly focus on using hydraulic oscillators to generate vibrations to alleviate slip pressure. These patents do not address changes to the movement of the bottom drill string assembly, and their effectiveness is limited. They cannot fundamentally solve the slip pressure problem because directional drilling commonly uses a PDC drill bit + single-steering single-bend screw drill string assembly. Figure 1 Because the screw centralizer 21 is close to the wellbore size and is in a non-rotating state during directional drilling, it generates significant axial frictional resistance and significantly affects cuttings transport. During drilling, cuttings tend to accumulate near the screw centralizer 21, leading to slip pressure. How to increase cuttings transport and wellbore cleanliness near the bottom of the well during sliding drilling, and avoid slip pressure, has become the primary problem faced by drilling companies in horizontal well construction. Summary of the Invention

[0005] To overcome the problem of drill cuttings accumulating near the stabilizer, leading to sliding and dragging pressure, this invention provides a rotary sand-cleaning and anti-drag drilling tool assembly and its usage method. This invention replaces the stabilizer on the single-bend single-stabilizer screw body with an independent anti-dragping short section located between the PDC drill bit and the unstabilizer screw, changing its motion state during sliding drilling, transforming it from sliding forward to rotating forward. This reduces axial frictional resistance while improving the wellbore cleaning effect near the bottom of the well, fundamentally solving the sliding and dragging pressure problem and greatly increasing the efficiency of directional drilling.

[0006] The technical solution adopted in this invention is as follows: A rotary sand-cleaning and anti-stress drilling tool assembly for drilling includes a drill bit, an anti-stress sub, a studless screw, and a flexible sub, wherein the drill bit, anti-stress sub, studless screw, and flexible sub are connected sequentially from bottom to top; the upper end of the flexible sub is provided with a back pressure valve.

[0007] The anti-pressure short section includes a male short section thread, a short section straightener, a reduced diameter section, and a female short section thread. The upper end of the short section straightener is connected to the male short section thread, and the lower end of the short section straightener is connected to the female short section thread. The reduced diameter section is located between the lower end of the short section straightener and the female short section thread.

[0008] The centralizer includes a centralizer body, centralizing ridges, flow channels, and high wear-resistant alloy pillars. There are three centralizing ridges, which are inclinedly arranged on the centralizer body. Multiple high wear-resistant alloy pillars are evenly welded onto each centralizing ridge. There are three flow channels, which are spaced apart from the centralizing ridges.

[0009] The outer diameter of the reduced diameter section is smaller than the outer diameter of the centralizer body.

[0010] The aforementioned unsupported screw is an unsupported single-bend screw, which is made by removing the straightener from the single-supported single-bend screw.

[0011] The lower end of the unsupported screw is connected to the anti-pressure short section via a screw drive head, and the upper end of the unsupported screw is connected to the flexible short section via a female thread.

[0012] The flexible sub section includes a female flexible sub section connector, a flexible sub section body, and a male flexible sub section connector connected from top to bottom.

[0013] The drill bit is a PDC drill bit, which is connected to the female thread of the lower end of the anti-pressure short section through the male thread of the drill bit.

[0014] The length of the anti-pressure short section is 0.5-0.7m.

[0015] A method for using a rotary sand-cleaning and anti-stress drilling tool assembly for drilling includes the following steps: First, connect the drilling tool assembly by sequentially connecting the drill bit, anti-stress sub, unsupported screw, flexible sub, and back pressure valve from bottom to top. Then, sequentially connect the MWD connector, non-magnetic drill collar, 6-8 heavy drill pipes, and several drill pipes. Second, during drilling, determine whether to perform directional drilling or composite drilling based on the trajectory adjustment requirements. When the wellbore trajectory matches the design trajectory, perform composite drilling directly. If the wellbore trajectory deviates from the design trajectory, use directional drilling to adjust the trajectory. After positioning the tool face according to the adjustment requirements, perform directional drilling.

[0016] The beneficial effects of this invention are: In this invention, a flexible short section is connected to the unsupported screw and topped with a back pressure valve. Its function is to adjust the characteristics of the drill string assembly, improve the directional drilling build-up rate and the stability of the composite drilling direction. No screw stabilizer is installed on the unsupported screw body, thus avoiding the sliding and pressure phenomenon of the screw stabilizer on the wellbore during sliding drilling.

[0017] In this invention, the anti-slip pressure short section is connected between the PDC drill bit and the unstabilized screw. During sliding drilling, it rotates at the same frequency as the PDC drill bit and the screw drive head, providing a rotational fulcrum for the drill string assembly. This serves both as a screw stabilizer, providing a fulcrum for sliding drilling, and, through high-speed rotation, decomposes the axial frictional resistance experienced by the anti-slip pressure short section into a larger circumferential frictional resistance and a smaller axial frictional resistance, thereby significantly reducing axial frictional resistance. Furthermore, the high-speed rotation and agitation of the anti-slip pressure short section significantly increases the cuttings carrying efficiency near the bottom of the well. The combined effect of these two factors fundamentally eliminates sliding pressure and significantly increases the efficiency of directional drilling.

[0018] This invention replaces the stabilizer on the single-bend single-stabilizer screw body with an independent anti-drag short section located between the PDC drill bit and the unstabilized screw, changing its motion state during sliding drilling, transforming it from sliding forward to rotating forward. This reduces axial frictional resistance while improving the wellbore cleaning effect near the bottom of the well, fundamentally solving the sliding drag problem and greatly increasing the efficiency of directional drilling. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the drill string assembly commonly used in the inclined sections of horizontal wells.

[0020] Figure 2 This is a schematic diagram of a drilling tool assembly structure for preventing slippage and pressure during drilling, provided by the present invention.

[0021] Figure 3 This is a schematic diagram of the anti-slipping short section in a drilling tool assembly for preventing slippage and slippage provided by the present invention.

[0022] Figure 4 This is a schematic diagram of the flexible short section in a drilling anti-slip pressure drill bit assembly provided by the present invention.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] In the figure, the attached figures are labeled as follows: 1. Drill bit; 2. Single-handle single-bend screw; 3. Back pressure valve; 4. Anti-slip short section; 5. Unsupported screw; 6. Flexible short section; 21. Screw stabilizer; 22. Screw drive head; 41. Male thread; 42. Centralizer; 421. Centralizer ridge; 422. Flow guide groove; 423. High wear-resistant alloy column; 43. Reduced diameter section; 44. Female thread; 51. Unsupported screw drive head; 61. Flexible short section female thread; 62. Flexible short section body; 63. Flexible short section male thread. Detailed Implementation

[0025] 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, not all, of the embodiments of the present invention. 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.

[0026] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] Example 1: To overcome the problem of drill cuttings accumulating near the stabilizer, leading to sliding and dragging, the present invention provides... Figure 2-4 The invention illustrates a rotary sand-cleaning and anti-stress drilling tool assembly and its usage method. The invention replaces the stabilizer on the single-bend, single-stabilizer screw body with an independent anti-stressing short section located between the PDC drill bit and the unstabilized screw, changing its motion state during sliding drilling, transforming it from sliding forward to rotating forward. This reduces axial frictional resistance while improving the wellbore cleaning effect near the bottom of the well, fundamentally solving the sliding stress problem and greatly increasing the efficiency of directional drilling.

[0028] A rotary sand-cleaning and anti-stress drilling tool assembly for drilling includes a drill bit 1, an anti-stress sub 4, a studless screw 5, and a flexible sub 6, wherein the drill bit 1, the anti-stress sub 4, the studless screw 5, and the flexible sub 6 are connected sequentially from bottom to top; a back pressure valve 3 is provided at the upper end of the flexible sub 6.

[0029] like Figure 2 and Figure 3 As shown, the flexible sub 6 is connected to the unsupported screw 5 and is connected to the back pressure valve 3. Its function is to adjust the characteristics of the drill string assembly, improve the sliding drilling build-up rate and the stability of the composite drilling. No screw stabilizer is installed on the unsupported screw 5 body, avoiding the sliding pressure phenomenon of the screw stabilizer on the wellbore during sliding drilling. The anti-pressure sub 4 is connected between the PDC drill bit 1 and the unsupported screw 5. During sliding drilling, it rotates at the same frequency as the PDC drill bit 1 and the unsupported screw drive head 51, providing a rotational fulcrum for this drill string assembly. This achieves the function of the screw stabilizer 21, providing a fulcrum for sliding drilling. Furthermore, the high-speed rotation of the anti-pressure sub 4 decomposes the axial frictional resistance experienced by the anti-pressure sub 4 into a larger circumferential frictional resistance and a smaller axial frictional resistance, thereby significantly reducing the axial frictional resistance. In addition, the high-speed rotation and agitation of the anti-pressure sub 4 significantly increases the cuttings carrying efficiency near the bottom of the well. The combined effect of these two factors fundamentally eliminates the sliding pressure situation and significantly increases the efficiency of directional drilling.

[0030] This invention replaces the stabilizer 21 on the single-bend single-stabilizer screw 2 with an independent anti-slip pressure short section 4 located between the PDC drill bit 1 and the unstabilized screw 5, optimizing its motion state during sliding drilling, changing it from sliding forward to rotating forward. This reduces axial frictional resistance while improving the wellbore purification effect near the bottom of the well, fundamentally solving the sliding pressure problem and greatly increasing the efficiency of directional drilling. Verified in over twenty horizontal wells in the Longdong shale oil field, it can shorten the average time from the second opening to the window entry point of oil horizontal wells by about two days. Furthermore, compared to ordinary directional drilling tool assemblies, the tool assembly in this invention significantly reduces the requirements for mud performance. Therefore, without affecting construction efficiency and downhole safety, the requirements for mud water loss, inhibition, and solids control can be appropriately relaxed, reducing mud cost input.

[0031] Example 2: Based on Embodiment 1, in this embodiment, preferably, the anti-pressure short section 4 includes a short section male buckle 41, a short section straightener 42, a reduced diameter portion 43, and a short section female buckle 44. The upper end of the short section straightener 42 is connected to the short section male buckle 41, and the lower end of the short section straightener 42 is connected to the short section female buckle 44. The reduced diameter portion 43 is located between the lower end of the short section straightener 42 and the short section female buckle 44.

[0032] Preferably, the centralizer 42 includes a centralizer body, centralizer ribs 421, flow guide grooves 422, and high wear-resistant alloy pillars 433. There are three centralizer ribs 421, which are inclinedly arranged on the centralizer body, and multiple high wear-resistant alloy pillars 423 are evenly welded on each centralizer rib 421. There are three flow guide grooves 422, which are spaced apart from the centralizer ribs 421.

[0033] Preferably, the outer diameter of the reduced diameter portion 43 is smaller than the outer diameter of the centralizer body.

[0034] like Figure 3 As shown, in this invention, the anti-slip pressure sub 4 comprises four parts, from top to bottom: a male thread 41, a stabilizer 42, a reduced-diameter section 43, and a female thread 44. The female thread end 44 is connected to the male thread of the PDC drill bit. The reduced-diameter section 43, by reducing the outer diameter of this section, lowers the rigidity of the anti-slip pressure sub 4 and even the entire drill string assembly, thereby increasing the slippage build-up rate and reducing slippage sections. The stabilizer 42 consists of three spiral stabilizer ribs 421 and three guide grooves 422. During drilling, the anti-slip sub 4 rotates at the same speed as the PDC drill bit 1, which is much higher than the speed of the stabilizer 21 on a regular single-screw drill. This results in the stabilizer 42 on the anti-slip sub 4 wearing out faster than the stabilizer 21 on a regular screw drill. To prevent the sliding drilling build-up rate from decreasing after the stabilizer 42 wears out, multiple high-wear-resistant alloy pillars 423 are evenly welded onto each stabilizer ridge 421 to improve the wear resistance of the stabilizer 42 and ensure it meets the wear resistance requirements at high speeds. The anti-slip sub 4 is connected to the female thread of the unstabilized screw drive head 51 via the male thread 41 at the upper end.

[0035] Preferably, the unsupported screw 5 is an unsupported single-bend screw, which is made by removing the straightener from the single-supported single-bend screw.

[0036] Preferably, the lower end of the unsupported screw 5 is connected to the anti-pressure short section 4 via the unsupported screw drive head 51, and the upper end of the unsupported screw 5 is connected to the flexible short section 6 via a female buckle.

[0037] In this invention, the unsupported screw 5 is an unsupported single-bend screw, which is achieved by eliminating the straightener 21 from the ordinary single-supported single-bend screw 2. The unsupported screw 5 is connected to the anti-pressure short section 4 through the female buckle of the lower drive head 51, and connected to the flexible short section 6 through the female buckle of the upper end.

[0038] Preferably, the flexible section 6 includes a flexible section female buckle 61, a flexible section body 62, and a flexible section male buckle 63 connected from top to bottom.

[0039] like Figure 4As shown, in this invention, the flexible short section is connected to the unsupported screw 5 via the lower male thread 63 and to the back pressure valve 3 via the upper female thread 61. The flexible short section 6 is used to reduce the overall rigidity of the drill string assembly, increase the directional drilling build-up rate, and simultaneously reduce the descent rate during composite drilling in deflection formations, thereby achieving a composite stabilization effect.

[0040] Preferably, the drill bit 1 is a PDC drill bit, which is connected to the female thread 44 at the lower end of the anti-pressure short section 4 via the male thread of the drill bit.

[0041] Preferably, the length of the anti-pressure short section 4 is 0.5-0.7m.

[0042] The key to this invention lies in achieving the drilling objectives by adjusting the overall length (0.5-0.7m) of the anti-slip pressure short section 4, the outer diameter (210-212mm) of the centralizer 42, and the outer diameter (130-150mm) and length (0-0.2m) of the reduced diameter section 43. Different target layers exist in different construction blocks, requiring optimization and adjustment within a given size range to simultaneously achieve stable sliding tool face, high sliding inclination rate, and good composite drilling inclination stabilization effect.

[0043] The preferred tool size for a 215.9mm wellbore in this invention is: PDC drill bit 1 has an outer diameter of 215.9 mm; Anti-pressure short section 4 has an overall length of 0.6m, a male thread end 41 with an outer diameter of 172mm, and a length (excluding threads) of 0.02m; The centralizer has an outer diameter of 211 mm and a length of 0.3 m. The reduced diameter section 43 has an outer diameter of 140mm and a length of 0.1m, while the female end 44 has an outer diameter of 172mm and a length of 0.18m.

[0044] The unsupported screw 5 is a 172mm outer diameter, 1.5° single-bend screw; The flexible short section 6 has a length of 1.1m, the female end 61 has an outer diameter of 172mm and a length of 0.2m, the body 62 has an outer diameter of 140mm and a length of 0.7m, and the male end 63 has an outer diameter of 172mm and a length of 0.2m. Back pressure valve 3 has an outer diameter of 172mm.

[0045] This embodiment preferably provides a method for using a rotary sand-cleaning and anti-stress drilling tool assembly. The specific steps are as follows: First, the drilling tool assembly is connected by connecting the drill bit 1, anti-stress sub 4, unsupported screw 5, flexible sub 6, and back pressure valve 3 from bottom to top. Then, the MWD connector, non-magnetic drill collar, weighted drill pipe 6-8, and several drill pipes are connected in sequence. Second, during drilling, directional drilling or composite drilling is determined according to the trajectory adjustment needs. When the wellbore trajectory matches the design trajectory, composite drilling is performed directly. If the wellbore trajectory deviates from the design trajectory, directional drilling is used to adjust the trajectory. After the tool face is positioned according to the adjustment needs, directional drilling is performed.

[0046] In this invention, during directional drilling, the stator and above of the unsupported screw 5 do not rotate. The PDC drill bit 1, the anti-slip section 4, and the screw rotor rotate simultaneously at high speed, matching the screw rotor's rotational speed. The anti-slip section 4 provides a rotational fulcrum for this drill assembly's directional drilling, thus fulfilling the function of the screw stabilizer 21 and providing a fulcrum for sliding drilling. Furthermore, the high-speed rotation decomposes the axial frictional resistance experienced by the anti-slip section 4 into a larger circumferential frictional resistance and a smaller axial frictional resistance, significantly reducing axial frictional resistance. Additionally, the high-speed rotation and agitation of the anti-slip section 4 significantly increases the cuttings carrying efficiency near the bottom of the well. The combined effect of these two factors fundamentally eliminates sliding slippage and significantly increases the efficiency of directional drilling.

[0047] During composite drilling, the entire drill string rotates, with the screw stator and above rotating at the same speed as the top drive (rotary table). The PDC drill bit 1, anti-slip sub 4, and screw rotor rotate at the same speed as the top drive (rotary table) and the screw rotor. The composite drilling effect is consistent with that of conventional directional drilling.

[0048] Specific usage method of this invention: 1. Drill string assembly connection: The PDC drill bit 1, anti-slip short section 4, unsupported screw 5, flexible short section 6, and back pressure valve 3 are connected sequentially from bottom to top. Then, the MWD connector, non-magnetic drill collar, weighted drill pipe 6-8 sections, and several ordinary drill pipes are connected sequentially on top. It should be noted that during directional drilling, the anti-slip short section rotates together with the unsupported screw drive head 51, interacting with the wellbore and cuttings, causing periodic fluctuations in drill string torque, which in turn leads to periodic fluctuations in the directional tool face, affecting the directional effect. Therefore, in this invention, the commonly used non-magnetic drill pipe is replaced with a non-magnetic drill collar, and the weighted drill pipe is increased from the conventional 3-5 sections to 6-8 sections. By increasing the rigidity of the lower drill string assembly, the fluctuation amplitude of the tool face is reduced, achieving a stable tool face and ensuring a smooth sliding effect.

[0049] II. Drilling Operation: During drilling, the decision to use directional drilling or composite drilling is made based on the trajectory adjustment requirements. If the wellbore trajectory matches the design trajectory, composite drilling is performed directly, with the operation method and parameters being the same as normal composite drilling. If the wellbore trajectory deviates from the design trajectory, directional drilling is used to adjust the trajectory. After positioning the tool face according to the adjustment requirements, directional drilling is carried out. It should be noted that ordinary directional drilling tools are prone to slippage and pressure build-up during directional drilling. Therefore, a point-braking method is required to alleviate the pressure build-up phenomenon by suddenly releasing and braking. Since there is no pressure build-up phenomenon in this project, the drilling pressure can be transmitted to the drill bit immediately. Therefore, the tool face is more sensitive to changes in drilling pressure. In order to ensure the stability of the tool face, the point-braking method used in conventional directional drilling cannot be used. Instead, a smooth and continuous drilling method is used to ensure that the torque at the drill bit is constant as much as possible, thus ensuring a good directional effect.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 this invention based on the specific circumstances.

[0051] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0052] The examples above are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention fall within the scope of protection of the present invention. Device structures and method steps not described in detail in this invention are prior art and will not be further described in this invention.

Claims

1. A rotary sand-cleaning and anti-stress drilling tool assembly for drilling, characterized in that: It includes a drill bit (1), an anti-pressure short section (4), a supportless screw (5), and a flexible short section (6), which are connected in sequence from bottom to top; the upper end of the flexible short section (6) is provided with a back pressure valve (3).

2. The rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 1, characterized in that: The anti-pressure short section (4) includes a short section male thread (41), a short section straightener (42), a reduced diameter section (43), and a short section female thread (44). The upper end of the short section straightener (42) is connected to the short section male thread (41), and the lower end of the short section straightener (42) is connected to the short section female thread (44). The reduced diameter section (43) is located between the lower end of the short section straightener (42) and the short section female thread (44).

3. The rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 2, characterized in that: The stabilizer (42) includes a stabilizer body, a stabilizer ridge (421), a guide groove (422), and a high wear-resistant alloy column (433). There are three stabilizer ridges (421), which are inclinedly arranged on the stabilizer body. Multiple high wear-resistant alloy columns (423) are evenly welded on each stabilizer ridge (421). There are three guide grooves (422), which are spaced apart from the stabilizer ridges (421).

4. The rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 2, characterized in that: The outer diameter of the reduced diameter portion (43) is smaller than the outer diameter of the centralizer body.

5. The rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 1, characterized in that: The aforementioned unsupported screw (5) is an unsupported single-bend screw, which is made by removing the straightener from the single-supported single-bend screw.

6. The rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 1, characterized in that: The lower end of the unsupported screw (5) is connected to the anti-pressure short section (4) through the screw drive head (51), and the upper end of the unsupported screw (5) is connected to the flexible short section (6) through the female buckle.

7. The rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 1, characterized in that: The flexible short section (6) includes a flexible short section female buckle (61), a flexible short section body (62), and a flexible short section male buckle (63) connected from top to bottom.

8. A rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 1, characterized in that: The drill bit (1) is a PDC drill bit, which is connected to the female thread (44) at the lower end of the anti-pressure short section (4) through the male thread of the drill bit.

9. A rotary sand-cleaning and anti-stress drilling tool assembly for drilling according to claim 1, characterized in that: The anti-pressure short section (4) is 0.5-0.7m long.

10. The method of using a rotary sand-cleaning and anti-stress drilling tool assembly according to any one of claims 1-9, characterized in that: The specific steps are as follows: First, connect the drill string assembly by connecting the drill bit (1), anti-slip short section (4), unsupported screw (5), flexible short section (6), and back pressure valve (3) from bottom to top. Then, connect the MWD connector, non-magnetic drill collar, heavy-duty drill pipe 6-8 column, and several drill pipes in sequence. Second, during drilling, determine whether to perform directional drilling or composite drilling according to the trajectory adjustment needs. When the wellbore trajectory matches the design trajectory, perform composite drilling directly. If the wellbore trajectory deviates from the design trajectory, use directional drilling to adjust the trajectory. After positioning the tool face according to the adjustment needs, perform directional drilling.

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