Drilling tool, drilling column and method for well drilling

Abstract

The invention relates to a drilling tool for drilling. The drilling tool comprises n short sections connected in series. Each short section comprises a first barrel body, a second barrel body connected with the first barrel body and a connecting piece connected with the second barrel body, the connecting piece of the ith short section is used for being connected with the first barrel body of the (i + 1) th short section, and the connecting piece of the ith short section is configured to enable the ith short section to deflect relative to the (i + 1) th short section. The drilling tool further comprises a damping mechanism arranged between the ith short section and the (i + 1) th short section. Wherein the damping mechanism is configured to be capable of reducing the deflection amplitude when the ith short section deflects relative to the (i + 1) th short section, n is larger than or equal to 2 and is an integer, and i is larger than or equal to 1 and smaller than or equal to n-1 and is an integer. The damping mechanisms between the short sections can solve the problem of track deviation in the horizontal drilling process, the bending damping of the drilling tool and the irregular movement of the drilling tool under the action of external force are increased, and the instability of a well track is reduced, so that more accurate horizontal well drilling is realized.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and more specifically to a drilling tool, drill string, and method for drilling. Background Technology

[0002] In existing technologies, flexible drilling tools are widely used in horizontal wells to ensure that the wellbore trajectory conforms to expectations, thereby achieving efficient drilling. However, conventional flexible drilling tools have significant limitations in maintaining wellbore trajectory stability. In actual drilling operations, due to the complexity of the formation and the adjustment and changes in drilling parameters, especially when encountering loose rock formations, hard rock formations, or fault zones, conventional flexible drilling tools move irregularly within the horizontal well section, making it difficult to accurately control the drill bit direction. This leads to increased lateral cutting by the drill bit and causes wellbore trajectory deviation. Summary of the Invention

[0003] In view of the above-mentioned problems existing in the prior art, the present invention provides a drilling tool, drill string and method for drilling, which can eliminate irregular lateral cutting of the drill bit, reduce wellbore trajectory deviation and achieve more precise drilling construction.

[0004] A first aspect of the present invention: providing a drilling tool for drilling, comprising,

[0005] n short sections connected in series, each short section including a first cylindrical body, a second cylindrical body connected to the first cylindrical body, and a connector connected to the second cylindrical body, wherein the connector of the i-th short section is used to connect to the first cylindrical body of the (i+1)-th short section, and the connector of the i-th short section is configured to allow the i-th short section to deflect relative to the (i+1)-th short section; and

[0006] The damping mechanism is located between the i-th short section and the (i+1)-th short section.

[0007] The damping mechanism is configured to reduce the deflection amplitude when the i-th short section deflects relative to the (i+1)-th short section, where n ≥ 2 and is an integer, and 1 ≤ i ≤ n-1 and is an integer.

[0008] Furthermore, the damping mechanism includes a piston rod disposed on the second cylinder of the i-th short section and a sleeve disposed on the first cylinder of the (i+1)-th short section.

[0009] The piston rod is inserted into the sleeve and defines a cavity for receiving damping fluid, so that the piston rod compresses the damping fluid when the i-th short section is deflected relative to the (i+1)-th short section.

[0010] Furthermore, the damping mechanism also includes an elastic element disposed outside the sleeve, with its two ends connected to the second cylinder of the i-th short section and the first cylinder of the (i+1)-th short section, respectively, so that the elastic element is subjected to compression or tension when the i-th short section deflects relative to the (i+1)-th short section.

[0011] Furthermore, each of the aforementioned short sections includes a first connecting portion and a second connecting portion for connecting to the second cylindrical body. The first connecting portion has a first concave surface, and the second cylindrical body has a first convex surface.

[0012] The first convex surface of the first connecting portion of the i-th short section is configured to fit against the first convex surface of the second cylinder of the (i+1)-th short section when deflection occurs.

[0013] Furthermore, both the first concave surface and the first convex surface are curved surfaces.

[0014] Furthermore, a first mounting groove and a second mounting groove are respectively provided on the first concave surface and the first convex surface for mounting the damping mechanism. The first mounting groove extends along the tangential direction of the first concave surface, and the second mounting groove extends along the tangential direction of the first convex surface.

[0015] Furthermore, the second connecting portion is provided with a second concave surface, and the second cylindrical body is provided with a second convex surface opposite to the second concave surface. The second concave surface and the second convex surface are configured to fit against the surface of the first connecting end of the connector when the connector is deflected relative to the second cylindrical body.

[0016] Furthermore, the second concave surface, the second convex surface, and the surface of the first connecting end are all arc surfaces.

[0017] Furthermore, the surface of the first connecting end is provided with a keyway, and the second cylinder is provided with a key extending into the keyway. The keyway extends along the axial direction of the short section so that the connecting member can deflect relative to the second cylinder.

[0018] Furthermore, the connector also includes a second connecting end and a limiting portion disposed between the first connecting end and the second connecting end.

[0019] The second connecting end of the i-th short section is configured to connect to the first cylinder of the (i+1)-th short section, so that the i-th short section is deflected relative to the (i+1)-th short section.

[0020] Furthermore, the limiting portion is configured to abut against the limiting surface between the first convex surface and the second convex surface when the connector deflects relative to the second cylinder, so as to limit the deflection amplitude.

[0021] A second aspect of the present invention provides a drill string for drilling, comprising the drill string described in any of the preceding claims, and drill bits and transition drill strings disposed at both ends of the drill string.

[0022] A third aspect of the present invention provides a method for drilling, for the drill string described above, comprising the following steps:

[0023] Step S1: Run the drill string into the build-up section and horizontal section of the horizontal well, so that the transition drill string is in the build-up section after the drill bit and the drill string enter the horizontal section;

[0024] Step S2: Drive the drill bit to drill in the horizontal section using the drill string at working drilling pressure.

[0025] The beneficial effects of this invention are as follows: The drilling tool provided by this invention comprises n short sections connected in series. Each short section includes a first cylinder, a second cylinder connected to the first cylinder, and a connector connected to the second cylinder. The connector of the i-th short section is used to connect to the first cylinder of the (i+1)-th short section, and the connector of the i-th short section is configured to allow the i-th short section to deflect relative to the (i+1)-th short section. The drilling tool also includes a damping mechanism disposed between the i-th and (i+1)-th short sections. The damping mechanism is configured to reduce the deflection amplitude when the i-th short section deflects relative to the (i+1)-th short section, where n ≥ 2 and is an integer, and 1 ≤ i ≤ n-1 and is an integer. The damping mechanism between the short sections can solve the trajectory deviation problem during horizontal drilling, increase the bending damping of the drilling tool, reduce the irregular movement of the drilling tool under external forces, and reduce wellbore trajectory instability, thereby achieving more precise horizontal well drilling. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Figure 1 The diagram shown is a partial structural schematic of a drilling tool used for drilling, viewed from one angle.

[0028] Figure 2 As shown Figure 1 The diagram shows a partial structural cross-sectional view of the drill string in one state.

[0029] Figure 3 As shown Figure 1 The diagram shows a partial structural cross-sectional view of the drill string in another configuration.

[0030] Figure 4 As shown Figure 1 The structural cross-sectional view of the first barrel of the short section of the drill bit shown.

[0031] Figure 5As shown Figure 1 The structural cross-sectional view of the second cylinder of the short section of the drill bit shown.

[0032] Figure 6 As shown Figure 1 The structural cross-sectional view of the connector of the short section of the drill bit shown.

[0033] Figure 7 As shown Figure 1 A schematic diagram of the damping mechanism of the drill bit shown from one perspective.

[0034] Figure 8 As shown Figure 7 The diagram shows a cross-sectional view of the damping mechanism.

[0035] In the figure, the following labels are used: 100, drilling tool; 10, sub-section;

[0036] 11. First cylinder; 111. First connecting part; 1111. First concave surface; 1112. First mounting groove; 1113. Connecting hole; 112. Second connecting part; 1121. Second concave surface; 1122. Communicating hole; 113. First stepped surface; 114. Second stepped surface;

[0037] 12. Second cylinder; 121. First end; 122. Second end; 1221. First convex surface; 1222. Second mounting groove; 1223. Second convex surface; 1224. Limiting surface; 123. Through hole; 124. Key;

[0038] 13. Connector; 131. First connecting end; 1311. Keyway; 132. Second connecting end; 133. Limiting part; 134. Channel;

[0039] 20. Damping mechanism; 20a. First damping mechanism; 20b. Second damping mechanism; 21. Sleeve; 211. Cavity; 22. Piston rod; 23. Elastic element. Detailed Implementation

[0040] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will now be described in detail with reference to the accompanying drawings. This drawing is a simplified schematic diagram, illustrating only the basic structure of the invention, and therefore only shows the components relevant to the invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] refer to Figures 1-3As shown, the present invention provides a drilling tool 100 for drilling, comprising n interconnected short sections 10. The i-th short section 10 and the (i+1)-th short section 10 are mutually deflectable, allowing the drilling tool 100 to smoothly pass through the downhole directional drilling section so as to feed the drill bit into the horizontal section. A damping mechanism 20 is provided between the i-th short section 10 and the (i+1)-th short section 10 to improve the stability of the drilling tool 100 during drill bit drilling, thereby reducing irregular lateral cutting by the drill bit and achieving more precise drilling operations. Wherein, n ≥ 2 and is an integer, and 1 ≤ i ≤ n-1 and is an integer.

[0042] In some embodiments, when the drill bit is drilling at the end of the horizontal section of a horizontal well, it experiences a reaction force from the bottom-hole rock formation. This reaction force is transmitted through the drill bit to the drill string 100, causing the drill string 100 to deform as it rotates around its own axis. At this time, the i-th and (i+1)-th sub-sections 10 of the drill string 100 deflect relative to each other. The damping mechanism 20 effectively reduces this deflection between the i-th and (i+1)-th sub-sections 10, keeping them as coaxial as possible, thereby effectively reducing irregular lateral cutting by the drill bit.

[0043] Combination Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments, each short section 10 has the same structure, including a first cylindrical body 11, a second cylindrical body 12 connected to the first cylindrical body 11, and a connector 13 disposed at the end of the second cylindrical body 12. For the (i+1)th short section 10, the first cylindrical body 11 of the (i+1)th short section 10 includes a first connecting portion 111 for connecting the i-th short section 10, and a second connecting portion 112 for connecting the second cylindrical body 12.

[0044] In some embodiments, the end of the first connecting portion 111 is provided with a first concave surface 1111 extending toward the second connecting portion 112. The end face of the first connecting portion 111 can fit against the end face of the second cylinder 12 of the adjacent short section 10 when deflection occurs. The end of the first connecting portion 111 is also provided with a first mounting groove 1112 for mounting a damping mechanism 20, so that the damping mechanism 20 is disposed between the i-th short section 10 and the (i+1)-th short section 10. Specifically, four first mounting grooves 1112 are provided, and the four mounting grooves are evenly arranged along the circumferential direction of the short section 10. Preferably, five, six or more first mounting grooves 1112 may also be provided.

[0045] In some preferred embodiments, the first concave surface 1111 is an arcuate surface extending toward the second connecting portion 112, preferably a spherical surface. Each of the first mounting grooves 1112 extends along the tangential direction of the first concave surface 1111.

[0046] In some embodiments, the first connecting portion 111 is provided with a connecting hole 1113 extending along its own axial direction for connecting the connecting member 13 of the i-th short section 10. The hole wall of the connecting hole 1113 and the connecting member 13 of the i-th short section 10 can be connected by a screw connection so as to transmit rotational power between the i-th short section 10 and the (i+1)-th short section 10.

[0047] In some embodiments, the end of the second connecting portion 112 is provided with a second concave surface 1121 extending toward the first connecting portion 111 for fitting the connector 13. The second concave surface 1121 is also an arc surface. Preferably, the second concave surface 1121 may also be a spherical surface.

[0048] In some embodiments, the second connecting portion 112 is provided with a connecting hole 1122 extending from the connecting hole 1113 to the second concave surface 1121.

[0049] Combination Figure 4 As shown, in this embodiment, the circumferential dimension of the first connecting portion 111 is larger than the circumferential dimension of the second connecting portion 112, such that a first stepped surface 113 is formed between the first connecting portion 111 and the second connecting portion 112. The first stepped surface 113 is used to abut against the end face of the second cylinder 12 when the first cylinder 11 and the second cylinder 12 are connected. The inner diameter of the connecting hole 1113 is larger than the inner diameter of the connecting hole 1122, such that a second stepped surface 114 is formed between the connecting hole 1113 and the connecting hole 1122. The second stepped surface 114 is used to abut against the connecting member 13 of the i-th short section 10. This allows the force to be transmitted between each short section 10 in the axial direction of the short section 10, so that the drill bit can apply drilling pressure to the rock strata at the end of the horizontal section through the drill bit 100, thereby improving drilling efficiency.

[0050] refer to Figure 2 , Figure 3 and Figure 5 As shown, in some embodiments, for the i-th short section 10, the second cylindrical body 12 of the i-th short section 10 includes a first end 121 for connecting to the first cylindrical body 11, and a second end 122 for connecting to the connector 13. The inner diameter of the first end 121 is larger than the outer diameter of the second connecting portion 112, so that the second cylindrical body 12 can be connected to the second connecting portion 112 of the first cylindrical body 11. In some embodiments, the second end 122 and the second connecting portion 112 can be connected by means of screwing, bolting, or other methods.

[0051] In this embodiment, after the second cylinder 12 is connected to the second connecting portion 112 of the first cylinder 11, the end face of the second end 122 abuts against the first step surface 113, so that the force along the axial direction of the short section 10 can be effectively transmitted between the first cylinder 11 and the second cylinder 12.

[0052] Combination Figure 5 As shown, in some embodiments, the outer edge of the second end 122 is provided with a first convex surface 1221 extending in a direction away from the first cylinder 11. The first convex surface 1221 can fit into the first concave surface 1111 of the (i+1)th short section 10. A second mounting groove 1222 for mounting the damping mechanism 20 is provided on the first convex surface 1221, and the second mounting groove 1222 corresponds one-to-one with the first mounting groove 1112 on the first cylinder 11 of the (i+1)th short section 10. Preferably, the second mounting groove 1222 extends tangentially to the first convex surface 1221. Inside the second end 122, a second convex surface 1223 extending in a direction away from the first cylinder 11 is provided for fitting the connector 13. The second convex surface 1223 is also an arc surface, preferably a spherical surface. A limiting surface 1224 is provided between the first convex surface 1221 and the second convex surface 1223 to abut against the connector 13 of the i-th short section 10 after the i-th short section 10 and the (i+1)-th short section 10 have deflected, thereby limiting the angle of deflection between the i-th short section 10 and the (i+1)-th short section 10. The limiting surface 1224 can be a cylindrical surface or a conical surface.

[0053] Combined again Figure 2 , Figure 3 and Figure 5 As shown, in some embodiments, a through hole 123 extending inwardly in the radial direction of the short section 10 is provided between the first end 121 and the second end 122 for mounting a key 124. The key 124 mounted in the through hole 123 can abut against the connector 13 so that the second cylinder 12 can connect to the connector 13. Preferably, four through holes 123 are provided, and the four through holes 123 are evenly arranged in the circumferential direction of the short section 10. It is understood that five, six or more through holes 123 may also be provided.

[0054] refer to Figure 2 , Figure 3 and Figure 6As shown, in some embodiments, the connector 13 of the i-th short section 10 includes a first connecting end 131 located within the second cylinder 12, a second connecting end 132 connecting the first cylinder 11 of the (i+1)-th short section 10, and a limiting portion 133 disposed at the first connecting end 131 and the second connecting end 132. The surface of the first connecting end 131 is arc-shaped, preferably spherical, for fitting the second concave surface 1121 and the second convex surface 1223. A keyway 1311 for accommodating the key 124 is provided on the first connecting end 131, and the keyway 1311 extends arc-shaped along the axial direction on the surface of the first connecting end 131 so that the end of the key 124 can slide within the keyway 1311. This allows the connector 13 to deflect relative to the second cylinder 12 between the second concave surface 1121 and the second convex surface 1223, thereby enabling deflection between the i-th and (i+1)-th short sections 10.

[0055] In some embodiments, when the i-th segment 10 and the (i+1)-th segment 10 deflect to a predetermined angle, the surface of the limiting portion 133 can abut against the limiting surface 1224. This allows the deflection angle between the i-th segment 10 and the (i+1)-th segment 10 to be limited.

[0056] In this embodiment, the second connecting end 132 is a cylindrical structure so as to be connected to the connecting hole 1113 of the (i+1)th short section 10.

[0057] In some embodiments, the connector 13 is provided with a channel 134 extending axially along the sub 10 for connecting the i-th sub 10 and the (i+1)-th sub 10 through a connecting hole 1122. This creates a flow channel within the drill string 100 for transporting fluid to the drill bit. During drilling, the fluid is drilling fluid.

[0058] refer to Figure 7 and Figure 8As shown, in some embodiments, the damping mechanism 20 includes a sleeve 21 connected within a first mounting groove 1112 of the (i+1)th short section 10, a piston rod 22 connected within a second mounting groove 1222 of the i-th short section 10, and an elastic element 23 disposed outside the sleeve 21 within the first mounting groove 1112 and the second mounting groove 1222 of the i-th short section 10. The closed end of the sleeve 21 is connected to the bottom of the first mounting groove 1112 of the (i+1)th short section 10, while the open end of the sleeve 21 extends toward the second mounting groove 1222 of the i-th short section 10. The fixed end of the piston rod 22 is connected to the bottom of the second mounting groove 1222 of the i-th short section 10, while the piston end of the piston rod 22 extends from the open end of the sleeve 21 into the interior of the sleeve 21, forming a sliding seal connection with the inner wall of the sleeve 21. Thus, the piston rod 22 defines a cavity 211 inside the sleeve 21 for filling with damping fluid. The damping fluid can be a gaseous fluid, a gas-liquid mixture, or a liquid fluid, including but not limited to inert gas, oil-gas mixture, or liquid oil.

[0059] In some embodiments, the damping fluid contained in the cavity 211 is a gaseous fluid or a gas-liquid mixture.

[0060] In one specific embodiment, the damping fluid is a gaseous fluid, such as an inert gas. When the piston rod 22 moves along the axial direction of the sleeve 21 and reduces the volume of the cavity 211, the damping fluid in the cavity 211 is compressed. Simultaneously, the damping fluid in the cavity 211 converts the mechanical energy of the (i+1)th short section 10 and the ith short section 10 deflecting each other into heat energy.

[0061] In another specific embodiment, the damping fluid is a gas-liquid mixture, such as an oil-gas mixture. When the piston rod 22 moves along the axial direction of the sleeve 21 and reduces the volume of the cavity 211, the volume of the gas components within the cavity 211 is compressed. Simultaneously, the damping fluid within the cavity 211 converts the mechanical energy of the (i+1)th short section 10 and the i-th short section 10 deflecting each other into heat energy. Furthermore, as the pressure within the cavity 211 increases, a portion of the gaseous components may liquefy.

[0062] In some other embodiments not shown, the piston rod 22 also defines a receiving cavity within the sleeve 21, and the receiving cavity is connected to the cavity 211 via a compression valve and a rebound valve. When the piston rod 22 moves along the axial direction of the sleeve 21 and causes a change in the volume of the cavity 211, the liquid damping fluid flows between the cavity 211 and the receiving cavity via the compression valve and the rebound valve to convert the mechanical energy of the (i+1)th segment 10 and the ith segment 10 deflecting each other into heat energy.

[0063] In some embodiments, the two ends of the elastic element 23 are respectively connected to the bottom of the first mounting groove 1112 of the (i+1)th short section 10 and the bottom of the second mounting groove 1222 of the i-th short section 10. When deflection occurs between the i-th short section 10 and the (i+1)th short section 10, the elastic element 23 is compressed or stretched under the combined action of the first mounting groove 1112 of the (i+1)th short section 10 and the second mounting groove 1222 of the i-th short section 10. Preferably, the elastic element 23 is a spring.

[0064] like Figure 2 As shown, when the i-th short section 10 and the (i+1)-th short section 10 are coaxial, all damping mechanisms 20 between the two short sections 10 are in normal operation. All keyways 124 of the i-th short section 10 are located in the middle of their respective keyways 1311.

[0065] like Figure 3 As shown, the i-th short section 10 and the (i+1)-th short section 10 are in a deflected state. When the i-th short section 10 deflects relative to the (i+1)-th short section 10 in the direction of arrow X, the first damping mechanism 20a in the direction of arrow X is compressed and is in a compressed state, while the second damping mechanism 20b away from the direction of arrow X is stretched and is in a stretched state. The end of the key 124 on the same side as the first damping mechanism 20a is located at the lower end of the corresponding keyway 1311, and the end of the key 124 on the same side as the second damping mechanism 20b is located at the upper end of the corresponding keyway 1311.

[0066] At this time, the elastic element 23 of the first damping mechanism 20a will push the i-th short section 10 to deflect away from the direction of arrow X, and the elastic element 23 of the second damping mechanism 20b will pull the i-th short section 10 to deflect away from the direction of arrow X. This allows the i-th short section 10 and the (i+1)-th short section 10 to return to a coaxial state. During this process, the end of the key 124 on the same side as the first damping mechanism 20a will slide back to the middle of the corresponding keyway 1311, and the end of the key 124 on the same side as the second damping mechanism 20b will slide back to the middle of the corresponding keyway 1311.

[0067] Because the drill bit transmits the reaction force of the rock at the bottom of the well to the drill string 100, the drill string 100 deforms rapidly as it rotates around its own axis. Therefore, the i-th short section 10 and the (i+1)-th short section 10 are... Figure 2 The state shown becomes Figure 3The state shown is a rapid and brief process. During this process, the damping fluid within each damping mechanism 20 exhibits high damping. The first damping mechanism 20a converts the mechanical energy of the i-th short section 10 during deflection into the elastic potential energy of the elastic element 23 and the thermal energy of the damping fluid, while simultaneously preventing the i-th short section 10 from deflecting in the direction of arrow X, thereby reducing the deflection amplitude of the i-th short section 10. The second damping mechanism 20b also converts the mechanical energy of the i-th short section 10 during deflection into the elastic potential energy of the elastic element 23 and the thermal energy of the damping fluid, while further preventing the i-th short section 10 from deflecting in the direction of arrow X, thereby further reducing the deflection amplitude of the i-th short section 10.

[0068] For the entire drill string 100, the combined action of all the damping mechanisms 20 between the various sections 10 effectively reduces the overall deflection amplitude of the drill string 100, improves the stability of the drill string 100, and thus effectively reduces the irregular lateral cutting of the drill bit. This reduces the deviation of the wellbore trajectory in horizontal wells, thereby achieving more precise drilling operations.

[0069] The present invention also provides a drill string for drilling, comprising a drill string 100, a drill bit connected to the lower end of the drill string 100, and a transition drill string connected to the upper end of the drill string 100. The transition drill string is a conventional flexible drill string in the prior art.

[0070] Based on the aforementioned drill string 100 and drill string, the present invention also provides a method for drilling, comprising the following steps.

[0071] In step S1, the drill string is lowered into the build-up section and horizontal section of the horizontal well, such that the transition drill string is in the build-up section after the drill bit and the drill string 100 enter the horizontal section.

[0072] In some implementations, the drill string is slowly lowered into the build-up and horizontal sections of the well with low drilling pressure. Because the drill string 100 passes through the build-up section slowly, the damping fluid within all damping mechanisms 20 of the drill string 100 exhibits low damping. After the drill string 100 passes through the build-up section and enters the horizontal section, the individual sections 10 of the drill string 100 return to a coaxial state under the action of all damping mechanisms 20.

[0073] In step S2, the drill bit is driven by the drill string 100 to drill in the horizontal section at working drilling pressure.

[0074] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0075] It should be understood that the terms "length", "width", "up", "down", "front and back", "left and right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0076] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A drilling tool for drilling, comprising, n short sections (10) connected in series, each of the short sections (10) including a first cylinder (11), a second cylinder (12) connected to the first cylinder (11), and a connector (13) connected to the second cylinder (12), wherein the connector (13) of the i-th short section (10) is used to connect to the first cylinder (11) of the (i+1)-th short section (10), and the connector (13) of the i-th short section (10) is configured to allow the i-th short section (10) to deflect relative to the (i+1)-th short section (10); and A damping mechanism (20) is disposed between the i-th short section (10) and the (i+1)-th short section (10). in, The damping mechanism (20) is configured to reduce the deflection amplitude when the i-th short section (10) deflects relative to the (i+1)-th short section (10), where n≥2 and is an integer, and 1≤i≤n-1 and is an integer.

2. The drilling tool for drilling according to claim 1, characterized in that, The damping mechanism (20) includes a piston rod (22) disposed on the second cylinder (12) of the i-th short section (10) and a sleeve (21) disposed on the first cylinder (11) of the (i+1)-th short section (10). The piston rod (22) is inserted into the sleeve (21) and defines a cavity (211) for receiving damping fluid, so that the piston rod (22) compresses the damping fluid when the i-th short section (10) is deflected relative to the (i+1)-th short section (10).

3. The drilling tool for drilling according to claim 2, characterized in that, The damping mechanism (20) further includes an elastic element (23) disposed outside the sleeve (21). The two ends of the elastic element (23) are respectively connected to the second cylinder (12) of the i-th short section (10) and the first cylinder (11) of the (i+1)-th short section (10), so that the elastic element (23) is compressed or stretched when the i-th short section (10) deflects relative to the (i+1)-th short section (10).

4. The drilling tool for drilling according to any one of claims 1-3, characterized in that, Each of the aforementioned short sections (10) has a first cylindrical body (11) including a first connecting portion (111) and a second connecting portion (112) for connecting to the second cylindrical body (12). The first connecting portion (111) is provided with a first concave surface (1111), and the second cylindrical body (12) is provided with a first convex surface (1221). The first convex surface (1221) of the first connecting part (111) of the i-th short section (10) is configured to fit with the first convex surface (1221) of the second cylinder (12) of the i+1 short section (10) when deflection occurs.

5. The drilling tool for drilling according to claim 4, characterized in that, Both the first concave surface (1111) and the first convex surface (1221) are curved surfaces.

6. The drilling tool for drilling according to claim 5, characterized in that, The first concave surface (1111) and the first convex surface (1221) are respectively provided with a first mounting groove (1112) and a second mounting groove (1222) for mounting the damping mechanism (20). The first mounting groove (1112) extends along the tangential direction of the first concave surface (1111), and the second mounting groove (1222) extends along the tangential direction of the first convex surface (1221).

7. The drilling tool for drilling according to claim 4, characterized in that, The second connecting part (112) is provided with a second concave surface (1121), and the second cylindrical body (12) is provided with a second convex surface (1223) opposite to the second concave surface (1121). The second concave surface (1121) and the second convex surface (1223) are configured to fit against the surface of the first connecting end (131) of the connector (13) when the connector (13) is deflected relative to the second cylindrical body (12).

8. The drilling tool for drilling according to claim 7, characterized in that, The surfaces of the second concave surface (1121), the second convex surface (1223), and the first connecting end (131) are all arc surfaces.

9. The drilling tool for drilling according to claim 7, characterized in that, The surface of the first connecting end (131) is provided with a keyway (1311), and the second cylinder (12) is provided with a key (124) extending into the keyway (1311). The keyway (1311) extends along the axial direction of the short section (10) so that the connecting member (13) can be deflected relative to the second cylinder (12).

10. The drilling tool for drilling according to claim 7, characterized in that, The connector (13) further includes a second connecting end (132) and a limiting part (133) disposed between the first connecting end (131) and the second connecting end (132). The second connecting end (132) of the i-th short section (10) is configured to connect to the first cylinder (11) of the (i+1)-th short section (10) so that the i-th short section (10) is deflected relative to the (i+1)-th short section (10).

11. The drilling tool for drilling according to claim 10, characterized in that, The limiting part (133) is configured to abut against the limiting surface (1224) between the first convex surface (1221) and the second convex surface (1223) when the connector (13) deflects relative to the second cylinder (12), so as to limit the deflection amplitude.

12. A drill string for drilling, characterized in that, It includes the drill string (100) as described in any one of claims 1-11, and drill bits and transition drill strings disposed at both ends of the drill string (100).

13. A method for drilling, characterized in that, The drill string used in claim 12 includes the following steps: Step S1: Run the drill string into the build-up section and horizontal section of the horizontal well, so that the transition drill string is in the build-up section after the drill bit and the drill string (100) enter the horizontal section; Step S2: Drive the drill bit in the horizontal section with working drilling pressure using the drill string (100).

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