Bottom drilling tool assembly, underground water exploration and drainage drilling deviation correcting system and deviation correcting method thereof

Abstract

The invention relates to the technical field of drilling, and provides a bottom drilling tool assembly, an underground water exploration and drainage drill hole deviation correcting system and a deviation correcting method thereof, and the bottom drilling tool assembly comprises a drill rod, a drill bit and a centralizer assembly; the centralizer assembly comprises a centralizer body, a first wear-resistant part and a second wear-resistant part, a plurality of ribs are arranged on the outer surface of the centralizer body in the axial direction, the ribs are evenly distributed in the circumferential direction of the centralizer body, and the outer edges of the tops of the ribs jointly define a virtual circumcircle; the first wear-resistant component and the second wear-resistant component are respectively arranged at two ends of the centralizer main body, and the first wear-resistant component is connected with a drill bit; the second wear-resistant part is connected with the drill rod; the diameters of the first wear-resistant part and the second wear-resistant part are both larger than or equal to the diameter of the circumcircle and are both smaller than the diameter of the drill bit. The wear resistance of the centralizer assembly is improved, the stability and reliability of a bottom drilling tool assembly are ensured, the drilling deviation rectifying effect can be improved, and the well track control capacity is optimized.

Description

Technical Field

[0001] The present invention relates to the field of drilling technology, and in particular to a bottom hole assembly, a downhole water exploration and drainage drilling correction system and a correction method thereof. Background Art

[0002] In many fields such as mineral exploration, tunnel engineering, geological disaster monitoring, oil and gas drilling, etc., the inclination (vertex angle) and azimuth of the borehole, that is, the drilling posture, play a vital role in ensuring project quality, assessing resource reserves, predicting geological risks, and optimizing construction plans.

[0003] In related technologies, during the construction of underground water exploration and drainage drilling, long-distance drilling is easily affected by factors such as uneven hardness of the stratum, changes in rock stratum inclination, and the swing of the bottom drill assembly itself, which may cause the borehole to deviate and affect the water exploration and drainage effect.

[0004] Among them, the swing of the bottom drill assembly itself is because the stabilizer is easily worn, which increases the gap between it and the hole wall and reduces the correction effect. Summary of the Invention

[0005] The present invention provides a bottom hole assembly, a downhole water exploration and drainage drilling correction system and a correction method thereof, which are used to solve at least one of the above-mentioned technical defects in the prior art, effectively improve the wear resistance of the stabilizer assembly, thereby ensuring the stability and reliability of the bottom hole assembly, improving the drilling correction effect, and optimizing the wellbore trajectory control capability.

[0006] A first aspect of the present invention provides a bottom hole assembly, comprising: Drill rods and drill bits; A centralizer assembly is located between the drill pipe and the drill bit, and the centralizer assembly includes: A centralizer body, the outer surface of which is provided with a plurality of ridges along the axial direction, the ridges being evenly distributed along the circumference of the centralizer body, the top outer edges of the ridges jointly defining a virtual circumscribed circle; the centralizer body having a first end and a second end disposed opposite to each other; a first wear-resistant component, provided at a first end of the centralizer body and connected to the drill bit; a second wear-resistant component, provided at the second end of the centralizer body and connected to the drill pipe; Wherein, the diameters of the first wear-resistant component and the second wear-resistant component are both greater than or equal to the diameter of the circumscribed circle, and the diameters of the first wear-resistant component and the second wear-resistant component are both smaller than the diameter of the drill bit.

[0007] According to the bottom hole assembly provided by the present invention, a plurality of first wear-resistant composite sheets are fixedly embedded on the surface of the first wear-resistant component, at least three of the first wear-resistant composite sheets form a group, each group is arranged at intervals along the axial direction of the first wear-resistant component, and the first wear-resistant composite sheets in each group are evenly distributed in the circumferential direction of the first wear-resistant component; and / or, A plurality of second wear-resistant composite sheets are fixedly embedded on the surface of the second wear-resistant component, and at least three second wear-resistant composite sheets form a group. Each group is arranged at intervals along the axial direction of the second wear-resistant component, and the second wear-resistant composite sheets in each group are evenly distributed in the circumferential direction of the second wear-resistant component.

[0008] According to the bottom hole assembly provided by the present invention, on the first wear-resistant component, the arrangement density of the first wear-resistant composite sheets decreases from a position close to the drill bit to a position far away from the drill bit.

[0009] According to the bottom hole assembly provided by the present invention, in a group of at least three first wear-resistant composite sheets, the circumferential angle between two adjacent first wear-resistant composite sheets is 120°; and / or, In a group of at least three second wear-resistant composite sheets, the circumferential angle between two adjacent second wear-resistant composite sheets is 120°.

[0010] According to the bottom hole assembly provided by the present invention, the first wear-resistant composite sheet and the second wear-resistant composite sheet are both made of tungsten carbide, diamond composite sheet or cubic boron nitride.

[0011] According to the bottom hole assembly provided by the present invention, the difference between the diameter of the first wear-resistant component and the diameter of the circumscribed circle ranges from 0.3 mm to 0.5 mm; And / or, the difference between the diameter of the second wear-resistant component and the diameter of the circumscribed circle is in a range of 0.3 mm to 0.5 mm.

[0012] According to the bottom hole assembly provided by the present invention, a plurality of first slag discharge grooves are provided on the surface of the first wear-resistant component along the axial direction, and the plurality of first slag discharge grooves are evenly distributed in the circumferential direction of the first wear-resistant component; and / or, A plurality of second slag discharge grooves are provided on the surface of the second wear-resistant component along the axial direction, and the plurality of second slag discharge grooves are evenly distributed in the circumferential direction of the second wear-resistant component.

[0013] A second aspect of the present invention provides a downhole water exploration and drainage drilling correction system, comprising any of the bottom hole assembly described above, and comprising: Ground control system; a top drive system connected to the ground control system for adjusting the rotational speed and torque; an automatic drill feed system connected to the ground control system for adjusting the drilling pressure; a mud pump connected to the ground control system for regulating flow; The bottom hole assembly is connected to the top drive system, the automatic drill feed system and the mud pump respectively. The bottom hole assembly is provided with a while drilling inclinometer and a high-frequency impact device. The while drilling inclinometer and the high-frequency impact device are connected to the ground control system.

[0014] A third aspect of the present invention provides a method for correcting the deviation of a downhole drilling hole for exploration and drainage of water, which is controlled based on the downhole drilling hole correction system for exploration and drainage of water, and includes the following steps: Obtain the inclination and azimuth of the borehole in real time; When the inclination angle is determined to be greater than or equal to the preset threshold, the drilling pressure and rotation speed are adjusted, and the inclination and azimuth of the borehole are continuously monitored within the target test section; When the deviation of the inclination angle increases for a preset number of consecutive times, automatic correction is triggered: the mud pump flow is controlled to change the hydraulic load of the drill tool, inducing the drill bit to cut sideways; the high-frequency short-stroke impact device is simultaneously started to enhance the active correction ability of the centralizer on the hole wall.

[0015] According to the downhole water exploration and drainage drilling correction method provided by the present invention, when the inclination angle is determined to be greater than or equal to a preset threshold, the bit pressure and the rotation speed are adjusted, including: Reduce the bit weight to 5-10kN, increase the rotation speed to 400-500rpm, and use the centrifugal force of the centralizer to suppress the upward tilt trend; Alternatively, increase the bit weight to 20-25kN and reduce the rotation speed to 200-300rpm to strengthen the lateral support force of the centralizer.

[0016] The bottom hole assembly (BHA) proposed in this invention utilizes an innovative structure for the centralizer assembly, combining ribs with wear-resistant components. This cleverly addresses the problem of traditional centralizer ends prone to wear and failure. The ribs provide efficient centralization and reduce friction, while high-hardness wear-resistant components provide focused protection for key vulnerable areas. Downhole safety is ensured by dimensionally controlled components (smaller than the drill bit diameter). This effectively enhances the wear resistance of the centralizer assembly, thereby ensuring the stability and reliability of the BHA, improving drilling deviation correction and optimizing wellbore trajectory control, thereby reducing drilling risks, improving drilling efficiency, and saving overall costs.

[0017] Specifically, first, ridges are provided axially on the outer surface of the centralizer body, and the centralizer body contacts the wellbore wall through the ridges. Compared with a light tube or a full-hole centralizer, the contact area between the centralizer body and the wellbore wall is reduced, which can effectively limit the lateral movement and deflection of the drill pipe in the wellbore, forcing the drill pipe to tend to be centered along the wellbore axis.

[0018] Secondly, the end areas where the centralizer body connects to the drill bit and drill pipe experience the most wear, due to relative motion, vibration, turbulence, and drilling fluid erosion. Wear in these areas of conventional centralizers can lead to loose connections, reduced strength, and even failure. However, the present invention provides a first wear-resistant component and a second wear-resistant component at each end of the centralizer body. These components act as "sacrificial layers," preferentially bearing wear and protecting the structural integrity of the centralizer body. By concentrating wear on replaceable or highly wear-resistant components, the higher-value, more complex centralizer body and its connecting threads are effectively protected, preventing the entire stabilizer from being scrapped due to end wear.

[0019] Furthermore, the diameters of both the first and second wear-resistant components are greater than or equal to the diameter of the circumscribed circle. This arrangement slows down the wear of the ridges, allowing each wear-resistant component to maintain the effective outer diameter of the centralizer body, ensuring stable and reliable centralizing throughout the centralizer's service life. This long-term maintenance of the centralizing function helps maintain the mechanical properties of the bottomhole assembly (such as its ability to increase, decrease, and stabilize inclination). Furthermore, the diameters of both the first and second wear-resistant components are smaller than the diameter of the drill bit. This arrangement ensures that the centralizer assembly (including the wear-resistant components) can smoothly pass through the wellbore created by the drill bit under all conditions, maintaining the designed wellbore diameter. If its diameter were equal to or greater than the drill bit diameter, the drill would be more susceptible to sticking during the run-in or run-out process at points of reduced borehole diameter, sections with large doglegs, or areas of wellbore collapse.

[0020] The downhole water exploration and drainage drilling correction system provided by the present invention comprises the above-mentioned bottom hole assembly and thus has all the advantages of the above-mentioned bottom hole assembly.

[0021] The downhole water exploration and drainage drilling correction method provided by the present invention can adjust the drilling tool posture in real time and improve the drilling trajectory control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1It is a schematic diagram of the structural decomposition of the bottom hole assembly provided by an embodiment of the present invention.

[0024] Figure 2 It is a cross-sectional schematic diagram of a centralizer body in a bottom hole assembly provided by an embodiment of the present invention.

[0025] Figure 3 It is a schematic cross-sectional view of the first wear-resistant component in the bottom hole assembly provided by an embodiment of the present invention.

[0026] Figure 4 It is a cross-sectional schematic diagram of the second wear-resistant component in the bottom hole assembly provided by an embodiment of the present invention.

[0027] Figure 5 This is a system block diagram of a downhole water exploration and release drilling correction system provided by an embodiment of the present invention.

[0028] Figure 6 This is one of the flow charts of the downhole water exploration and release drilling correction method provided by an embodiment of the present invention.

[0029] Figure 7 This is the second flow chart of the downhole water exploration and drainage drilling correction method provided by an embodiment of the present invention.

[0030] Reference numerals: 10. Drill rod; 20. Drill bit; 30. Centralizer assembly; 31. Centralizer body; 311. First end; 312. Second end; 32. Ridge; 33. First wear-resistant component; 331. First slag discharge chute; 34. Second wear-resistant component; 341. Second slag discharge chute; 35. First wear-resistant composite sheet; 36. Second wear-resistant composite sheet; C. circumcircle. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0033] In the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0035] Figure 1 It is a schematic diagram of the structural decomposition of the bottom hole assembly provided by an embodiment of the present invention. Figure 2 It is a cross-sectional schematic diagram of a centralizer body in a bottom hole assembly provided by an embodiment of the present invention.

[0036] See Figure 1 and Figure 2 An embodiment of the present invention provides a bottom hole assembly, which includes a drill pipe 10, a drill bit 20 and a stabilizer assembly 30. The drill pipe 10 mainly provides power transmission and mud channels, and the drill bit 20 is mainly responsible for crushing rocks.

[0037] The centralizer assembly 30 is located between the drill pipe 10 and the drill bit 20 and is mainly used to stabilize the wellbore trajectory and protect the drilling tools. The centralizer assembly 30 includes a centralizer body 31, a first wear-resistant component 33 and a second wear-resistant component 34.

[0038] The centralizer body 31 is a cylindrical or approximately cylindrical tubular structure, usually made of high-strength alloy steel. There are through holes inside the centralizer body 31 to ensure smooth flow of drilling fluid (mud).

[0039] The outer surface of the centralizer body 31 is machined with a plurality of (usually 3-6) raised ribs (i.e., ridges 32) along the axial direction (parallel to the axis of the drill pipe 10). The ridges 32 are evenly distributed along the circumference of the centralizer body 31. For example, three ridges 32 are distributed at 120 degrees, and four ridges 32 are distributed at 90 degrees. Three or four ridges are common. In soft formations or large wellbores, more ridges (e.g., six ridges) may be used to increase stability. In hard formations or small-clearance wellbores, the number of ridges (e.g., three ridges) may be reduced to reduce torque and resistance.

[0040] The cross-sectional shape of the ribs 32 can be rectangular, trapezoidal, arcuate (e.g., "blade-wing"), or a combination thereof. A trapezoidal or arcuate top shape helps reduce the risk of drill sticking and improve mud flow. Ribs 32 can be completely axial (straight) or designed with a low-angle helical shape. Helical ribs provide a degree of rotational stability and help smooth vibrations, but straight ribs are more commonly used in applications where rigidity and stable tilting are essential.

[0041] To resist wear, the surface of the ridges 32 can be built with hard alloy (such as tungsten carbide particles), embedded with hard alloy blocks, or entirely constructed of wear-resistant alloy steel. The top outer edges of each ridge 32 collectively define a virtual circumscribed circle C. In other words, the highest points (top outer edges) of all ridges 32 collectively define a virtual circumscribed circle C. The diameter of circumscribed circle C represents the "nominal stable diameter" of the centralizer body 31 in the wellbore.

[0042] The centralizer body 31 has a first end 311 (near the drill bit) and a second end 312 (near the drill pipe) facing each other. A first wear-resistant component 33 is provided at the first end 311 of the centralizer body 31 and is directly connected to the drill bit 20 (typically, a joint or gauge portion of the drill bit 20) by threaded connection or other reliable means. The outer diameter of the first wear-resistant component 33 is designed to be greater than or equal to the diameter of the circumscribed circle C defined by the top of the ridge 32 of the centralizer body 31, but strictly smaller than the diameter of the connected drill bit 20.

[0043] The second wear member 34 is located at the second end 312 of the centralizer body 31 and is directly connected to the upper drill pipe 10 (or other BHA components, such as the weighted drill pipe 10 or a jar) by threaded connection or other reliable means. The outer diameter of the second wear member 34 is designed to be greater than or equal to the diameter of the circumscribed circle C defined by the top of the ridge 32 of the centralizer body 31, but strictly smaller than the diameter of the connected drill bit 20.

[0044] The first and second wear-resistant components 33, 34 are designed as removable collars or bushings, attached to the ends of the centralizer body 31 via threads, locking pins, or an interference fit. When wear becomes severe, only the wear sleeves need to be replaced, eliminating the need to replace the entire centralizer body 31, resulting in improved economics. In this embodiment of the present invention, each wear-resistant component is internally machined with standard API or special threads for connection to the drill bit 20 and drill pipe 10. The connections must be sufficiently strong.

[0045] As can be understood, the bottom hole assembly provided by the present invention, through its innovative structure of the centralizer assembly 30, combines ribs 32 with wear-resistant components. This cleverly addresses the problem of traditional centralizer ends prone to wear and failure. Ribs 32 provide efficient centralization and reduce friction, while high-hardness wear-resistant components provide focused protection for key vulnerable areas. Downhole safety is ensured by dimensional control (smaller than the diameter of the drill bit 20). This effectively enhances the wear resistance of the centralizer assembly, thereby ensuring the stability and reliability of the bottom hole assembly, improving drilling deviation correction, and optimizing wellbore trajectory control, thereby reducing drilling risks, improving drilling efficiency, and saving overall costs.

[0046] Specifically, first, a ridge 32 is axially provided on the outer surface of the centralizer body 31. The centralizer body 31 contacts the wellbore wall through the ridge 32. Compared with a light tube or a full-hole centralizer, the contact area between the centralizer body 31 and the wellbore wall is reduced, which can effectively limit the lateral movement and deflection of the drill pipe 10 in the wellbore, forcing the drill pipe 10 to tend to be centered along the wellbore axis.

[0047] Secondly, the end areas where the centralizer body 31 connects to the drill bit 20 and drill pipe 10 are subject to the most severe wear, due to relative movement, vibration, turbulence, and drilling fluid erosion. Wear in these areas of conventional centralizers can lead to loose connections, reduced strength, and even failure. However, the present invention provides a first wear-resistant component 33 and a second wear-resistant component 34 at each end of the centralizer body 31, allowing each wear-resistant component to act as a "sacrificial layer," preferentially bearing wear and protecting the structural integrity of the centralizer body 31. By concentrating wear on replaceable or highly wear-resistant wear-resistant components, the higher-value, more complex centralizer body 31 and its connecting threads are effectively protected, avoiding overall scrapping due to end wear and reducing replacement frequency.

[0048] Furthermore, the diameters of the first and second wear-resistant components 33, 34 are both greater than or equal to the diameter of the circumscribed circle C. This arrangement slows the wear of the ribs 32, and the wear-resistant components maintain the effective outer diameter of the centralizer body 31, ensuring stable and reliable centralizing throughout the centralizer's service life. This long-term maintenance of the centralizing function helps maintain the mechanical properties of the bottomhole assembly (such as its ability to increase, decrease, and stabilize inclination). Furthermore, the diameters of the first and second wear-resistant components 33, 34 are both smaller than the diameter of the drill bit 20. This arrangement ensures that the centralizer assembly 30 (including the wear-resistant components) can smoothly pass through the wellbore drilled by the drill bit 20 under all conditions, maintaining the designed wellbore diameter. If its diameter were equal to or greater than the diameter of the drill bit 20, the drill would be more likely to get stuck during the run-in or pull-out process at reduced borehole diameters, dogleg sections, or wellbore collapses.

[0049] Figure 3 It is a schematic cross-sectional view of the first wear-resistant component in the bottom hole assembly provided by an embodiment of the present invention. Figure 4 It is a cross-sectional schematic diagram of the second wear-resistant component in the bottom hole assembly provided by an embodiment of the present invention.

[0050] Continue reading Figure 1 , and also see Figure 3 and Figure 4 In some embodiments of the present invention, a plurality of first wear-resistant composite sheets 35 are fixedly embedded in the surface of the first wear-resistant component 33. These first wear-resistant composite sheets 35 can be ultra-hard wear-resistant composite sheets, including tungsten carbide, diamond composite sheets (PDC), or cubic boron nitride composite sheets (PCBN). These sheets typically consist of an extremely thin (0.5 mm to 2 mm) but extremely hard and wear-resistant layer of polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PCBN) sintered onto a cemented carbide (tungsten carbide) substrate.

[0051] Diamond compacts (PDC) are suitable for abrasive formations (sandstone, conglomerate, etc.) and most soft to medium-hard formations. They offer optimal wear resistance and a low coefficient of friction. Cubic boron nitride compacts (PCBN) are slightly less hard than PDC but offer greater thermal stability and impact resistance, making them suitable for hard and extremely abrasive formations or high-temperature wellbore sections.

[0052] The first wear-resistant composite sheet 35 is typically circular, but can also be elliptical, rectangular, or other shapes to suit specific locations. It covers 10-20% of the surface of the first wear-resistant component 33. The diameter of the first wear-resistant composite sheet 35 is preferably slightly larger than the designed embedment depth, which is 2-3 mm, forming a small protrusion (0.5 mm to 2 mm).

[0053] At least three first wear-resistant composite sheets 35 form a group, that is, each group contains at least three wear-resistant composite sheets, and each group of first wear-resistant composite sheets 35 is arranged at intervals along the axial direction of the first wear-resistant component 33, and each group of first wear-resistant composite sheets 35 is evenly distributed in the circumferential direction, that is, the wear-resistant composite sheets in the same group are evenly distributed in the circumferential direction of the wear-resistant component, for example: 3 sheets per group, each sheet is spaced 120 degrees apart; or 4 sheets per group, each sheet is spaced 90 degrees apart; or 6 sheets per group, each sheet is spaced 60 degrees apart, to ensure that each group can form a symmetrical and stable support point on the circumference.

[0054] Three wear-resistant composite sheets form a stable triangular support, while four or six sheets provide more uniform support and wear resistance, but the cost and processing complexity increase. The specific selection is based on the abrasiveness of the formation, wellbore size, and expected life.

[0055] In addition, the number of groups is determined based on the axial length of the wear-resistant component and the severity of wear. Typically, there are at least two groups, and critical areas may require three or more. The distance between groups needs to be balanced: close enough to provide continuous wear protection, yet far enough apart to avoid stress concentration, allow the mud flow channel to dissipate heat and chips, and reduce processing difficulty and cost. Adjacent groups of composite plates can be aligned or staggered in the circumferential direction (e.g., 60-degree or 45-degree staggered). Staggered arrangements provide more uniform wear distribution and better surface coverage, reducing the risk of notch wear in unprotected areas.

[0056] A plurality of second wear-resistant composite sheets 36 are fixedly embedded in the surface of the second wear-resistant component 34. The shape and arrangement of the second wear-resistant composite sheets 36 are the same as those of the first wear-resistant composite sheets 35 described above, and the specific arrangement thereof is similar to that of the first wear-resistant composite sheets 35. At least three second wear-resistant composite sheets 36 form a group, and each group of second wear-resistant composite sheets 36 is spaced apart along the axial direction of the second wear-resistant component 34, and each group of second wear-resistant composite sheets 36 is evenly distributed in the circumferential direction.

[0057] In other words, the array scheme of the wear-resistant composite sheet can be applied to the first wear-resistant component 33 (drill bit end) alone, or to the second wear-resistant component 34 (drill rod end) alone, or to both the first wear-resistant component 33 (drill bit end) and the second wear-resistant component 34 (drill rod end), mainly determined according to the specific working conditions and wear expectations (the drill bit end usually bears greater impact and drilling pressure, and the drill rod end bears longer rotational friction).

[0058] During machining, blind holes (inlay holes) matching the shape and dimensions of the composite sheet are machined into the outer surface of the wear-resistant component (usually a steel or carbide substrate). The hole depth is slightly less than the thickness of the composite sheet, allowing the protruding portion of the composite sheet to first contact the wellbore wall, bearing the primary friction and wear, thereby maximizing protection for the wear-resistant component. The composite sheet protruding from the wear-resistant component acts as sacrificial wear-resistant bumps. Wear primarily occurs at these bumps, while the wear-resistant component beneath them remains protected. Even after the composite sheet wears flush with the wear-resistant component, its remaining portion and the wear-resistant component still provide some protection. The composite sheet is secured in the hole using an interference fit (cold pressing) or, more reliably, high-temperature brazing. Brazing uses high-strength silver- or copper-based filler metals to ensure a strong metallurgical bond between the composite sheet and the substrate, capable of withstanding high impact and shear forces.

[0059] This embodiment of the present invention utilizes "sacrificial bumps" made of ultrahard material to achieve lattice-type protection, maximizing wear resistance. Discrete contact also optimizes friction, heat dissipation, and mud flow. This effectively maintains the righting function and protects critical connections. By reducing tripping times, increasing drilling speed, and reducing accident risks, this approach significantly improves the economic efficiency and safety of drilling operations.

[0060] In some embodiments of the present invention, the density of the first wear-resistant composite sheets 35 decreases from near the drill bit 20 to farther away from the drill bit 20 on the first wear-resistant component 33, with a density of ≥8 sheets / cm² near the drill bit end and ≤5 sheets / cm² away from the drill bit end. This axial density gradient design matches the wear gradient, balances wear resistance with WOB transmission efficiency, and improves overall performance and lifespan.

[0061] The area near the drill bit end (high wear zone) experiences the most intense wear within the entire centralizer assembly 30. The intense vibration and shock waves generated by the drill bit 20 breaking rock are first transmitted to the near-bit end of the first wear-resistant component 33, which is directly connected to it. The weight on bit (WOB) is then transmitted through the drill pipe 10 and ultimately acts on the drill bit 20. This reaction force places significant pressure on the connection between the drill bit 20 and the centralizer, exacerbating friction between this area and the wellbore wall. Meanwhile, as the axial distance away from the drill bit end (the wear-reducing zone) increases, vibration, shock, WOB concentration, linear velocity, and direct erosion by the drilling fluid all significantly decrease, leading to a corresponding decrease in wear.

[0062] By placing more and denser wear-resistant composite sheets in the high-density area (near the drill bit end), a solid "shield" is formed, providing the strongest defense against the harshest wear environments. This ensures that critical areas have the highest wear resistance reserves, effectively slowing the wear rate and preventing premature failure. Fewer and more sparse wear-resistant composite sheets are placed in the low-density area (away from the drill bit end). Because wear in this area is relatively light, excessively high density would waste resources (expensive composite sheet costs) and unnecessarily increase frictional resistance. A lower density is sufficient to meet the wear resistance requirements of this area.

[0063] In some embodiments of the present invention, the circumferential angle between two adjacent first wear-resistant composite sheets 35 in each group of first wear-resistant composite sheets 35 is 120°; or the circumferential angle between two adjacent second wear-resistant composite sheets 36 in each group of second wear-resistant composite sheets 36 is 120°. Alternatively, three wear-resistant composite sheets are provided on each wear-resistant component to form a stable triangular support.

[0064] In some embodiments of the present invention, the difference between the diameter of the first wear-resistant component 33 and the diameter of the circumscribed circle C is in the range of 0.3 mm to 0.5 mm; alternatively, the difference between the diameter of the second wear-resistant component 34 and the diameter of the circumscribed circle C is in the range of 0.3 mm to 0.5 mm. Alternatively, the difference between the diameter of the first wear-resistant component 33 and the diameter of the second wear-resistant component 34 and the diameter of the circumscribed circle C is in the range of 0.3 mm to 0.5 mm.

[0065] Continue reading Figure 3 and Figure 4 In some embodiments of the present invention, the surface of the first wear-resistant component 33 is provided with a plurality of first slag removal grooves 331 along the axial direction. The cross-section of the first slag removal grooves 331 is typically U-shaped, V-shaped, or trapezoidal, with a smooth bottom transition to reduce stress concentration. U-shaped grooves provide a large volume and smooth mud passage, while V-shaped grooves facilitate cuttings guidance and self-cleaning.

[0066] Multiple first slag discharge grooves 331 are evenly distributed around the circumference of the first wear-resistant component 33. The number of first slag discharge grooves 331 is usually 3 to 6 (matching or multiples of the number of ridges 32 of the centralizer body 31). For example, when three first slag discharge grooves 331 are arranged in a circumferential array, two adjacent first slag discharge grooves 331 are arranged at an interval of 120° to ensure uniform slag discharge and force in the circumferential direction.

[0067] The first slag troughs 331 can be designed between the various groups of first composite sheets or staggered with the first composite sheets to avoid cutting the sheets. The structure of the first slag troughs 331 increases the contact surface area between the first wear-resistant components 33 and the drilling fluid, providing a cooling and cleaning channel for the first composite sheets. The high-speed mud flowing through the first slag troughs 331 forcibly flushes the trough walls, efficiently removing frictional heat (from friction between the first composite sheets or the first wear-resistant components 33 and the wellbore wall), preventing overheating and failure of the composite sheets (especially protecting heat-sensitive PDC composite sheets).

[0068] The second wear-resistant component 34 is provided with a plurality of second slag discharge grooves 341 along the axial direction. The plurality of second slag discharge grooves 341 are evenly distributed around the circumference of the second wear-resistant component 34. The shape and arrangement of the second slag discharge grooves 341 are the same as those of the first slag discharge grooves 331. The arrangement of the second slag discharge grooves 341 is similar to that of the first slag discharge grooves 331.

[0069] The slag discharge trough can be configured for the first wear-resistant component 33 (drill bit end), the second wear-resistant component 34 (drill rod end), or both, depending on the specific operating conditions. The slag discharge trough width can be set to 20-30 mm to ensure timely discharge of rock dust and prevent accumulation that could affect correction accuracy and drilling efficiency.

[0070] Figure 5 This is a system block diagram of a downhole water exploration and release drilling correction system provided by an embodiment of the present invention.

[0071] See Figure 5 An embodiment of the present invention further provides a downhole water exploration and drainage drilling and correction system, which includes a top drive system, an automatic drill feed system, a ground control system, a mud pump and a bottom drill assembly of any one of the above items, the bottom drill assembly is connected to the top drive system, the automatic drill feed system and the mud pump respectively, and a downhole inclinometer and a high-frequency impact device are provided on the downhole inclinometer and the high-frequency impact device, which are connected to the ground control system.

[0072] The inclinometer is installed on the bottomhole assembly (BHA) and can be embedded in the stabilizer assembly or set close to the drill bit. The inclinometer is used to monitor the borehole inclination (θ) and azimuth (ψ) in real time, and the monitoring data is fed back to the ground control system through mud pulses or electromagnetic waves.

[0073] The ground control system, serving as the core decision-making hub, receives data from the inclinometer while drilling and sends control commands to other execution systems based on preset thresholds. Based on the preset drilling trajectory and real-time data, the ground control system calculates correction commands and sends them to the automatic drill feed system (to adjust the bit weight), the top drive system (to adjust the speed and torque), the high-frequency percussion device (to adjust the frequency and stroke), and the mud pump (to adjust the flow rate).

[0074] The top drive system serves as a rotary power source, driving the drill pipe and drill bit, and is used to adjust speed and torque. The automatic drill feed system is linked to the top drive system, adjusting the weight on bit by controlling the feed of the drill pipe. A high-frequency percussion device, integrated into the bottom hole assembly's near-bit stabilizer, generates instantaneous lateral force, allowing the centralizer assembly to embed into the hole wall to form a fulcrum. The high-frequency percussion device is used to adjust frequency and stroke. The mud pump provides mud circulation power for the entire system. Fluctuations in its flow rate affect the hydraulic state of the bottom hole assembly, and the mud pump is used to regulate flow.

[0075] Furthermore, each execution system (automatic drill feed system, top drive system, high-frequency percussion device, and mud pump) provides status feedback to the surface control system. Based on the measured data and pre-set algorithms, the surface control system generates control instructions and sends them to each execution system. The mud pump then pumps mud through the drill pipe into the bottomhole assembly (BHA), completing the circulation process.

[0076] Specifically, the flow of control instructions for the underground water exploration and drainage drilling and correction system is shown in the following table:

[0077] The flow of data feedback from the underground water exploration and drainage drilling correction system is shown in the following table:

[0078] It can be understood that the downhole water exploration and drainage drilling correction system provided in the embodiment of the present invention includes the above-mentioned bottom hole assembly and therefore has all the advantages of the above-mentioned bottom hole assembly.

[0079] Figure 6 This is one of the flow charts of the downhole water exploration and release drilling correction method provided by an embodiment of the present invention. Figure 7 This is the second flow chart of the downhole water exploration and drainage drilling correction method provided by an embodiment of the present invention.

[0080] See Figure 6 and Figure 7 The embodiment of the present invention further provides a method for correcting the inclination of a downhole drilling hole by using a water exploration and discharge method, which is controlled based on the above-mentioned downhole drilling hole correction system for using a water exploration and discharge method, and includes the following steps: Step S100: Acquire the inclination and azimuth of the borehole in real time.

[0081] Initial parameter setting module: Based on the formation lithology (sandstone / shale compressive strength σ_c) and crushing index K, the drilling pressure (P) is matched to 10-25 kN, the drilling speed (N) is matched to 200-400 rpm, and the mud flow rate (Q) is matched to 80-150 L / min. Based on the formation lithology (e.g., sandstone, shale) and the degree of crushing, the inclination (θ) and azimuth (ψ) of the borehole are monitored in real time using a wireless while-drilling inclinometer.

[0082] Step S200: When it is determined that the inclination angle is greater than or equal to a preset threshold, the drilling pressure and rotation speed are adjusted, and the inclination angle and azimuth angle of the borehole are continuously monitored within the target test section (eg, 10 m).

[0083] When the inclination angle (θ) exceeds a preset threshold (e.g., ±1.5° / 100m), the drilling pressure and rotational speed are adjusted. The automatic drill feed system reduces the drilling pressure to reduce lateral cutting forces. The top drive system increases the rotational speed to enhance the centrifugal straightening effect.

[0084] Specifically, when the inclination angle (θ) exceeds ±1.5° / 100m, the drill can be corrected by reducing the WOB by 5-10kN and increasing the rotational speed to 400-500rpm. This allows the centrifugal force of the centralizer to suppress the upward tilt and achieve a downward correction. Alternatively, the drill can be corrected by increasing the WOB to 20-25kN and reducing the rotational speed to 200-300rpm, strengthening the lateral support of the centralizer.

[0085] Specifically, the inclination angle θ is monitored by a wireless inclinometer while drilling. When |Δθ|>1.5° / 100m: Incline-down mode: P is lowered to 5-10kN, N is increased to 400-500rpm, and centrifugal force is used to suppress pitching up; Incline-up mode: P is increased to 20-25kN, N is reduced to 200-300rpm, and lateral support is enhanced.

[0086] Step S300: When it is determined that the deviation of the inclination angle increases for a preset number of consecutive times, automatic correction is triggered: the mud pump flow is controlled to change the hydraulic load of the drill tool to induce lateral cutting of the drill bit; and the high-frequency short-stroke impact device is synchronously started to enhance the active correction ability of the centralizer on the hole wall.

[0087] Specifically, when deviations occur three times in a row, the prediction model controls the mud pump flow (±20L / min) to change the hydraulic load of the drill tool and induce lateral cutting of the drill bit; the high-frequency short-stroke impact device (frequency 50-100Hz, stroke 2-3mm) is simultaneously started to enhance the centralizer's ability to actively correct the hole wall.

[0088] The correction path prediction model is based on the historical inclination measurement data (θ0, θ1, ..., θ n ) and rock formation parameters (compressive strength σ_c, layer thickness h, anisotropy coefficient α) to establish a finite element-fuzzy PID composite control model, output the optimal drilling pressure-speed matching curve and impact frequency parameters, calculate the optimal correction path, and establish a drilling trajectory prediction model.

[0089] The changes in the inclination angle (θ) of the borehole are monitored every 0.3m. When the inclination angle (θ) continues to deviate, the mud pump flow rate is controlled (+5L / min) to change the hydraulic load of the drill tool and induce the drill bit to cut sideways. The high-frequency short-stroke impact device (frequency +10Hz) is simultaneously activated to enhance the centralizer's ability to actively correct the hole wall.

[0090] This invention takes a coal mine water exploration and drainage drilling (designed hole depth 400m, target layer sandstone) as an example: The wear-resistant parts are formed on the main body of the centralizer by welding 30CrMnSiA alloy steel. The outer diameter of the wear-resistant parts is 73.5mm (the designed drilling diameter is 75mm). Tungsten carbide composite sheets (grain size 80 mesh) are fixedly embedded on the wear-resistant parts. Three sets of slag discharge grooves are opened on the side walls of each wear-resistant part.

[0091] Set the initial drilling weight to 18kN, the rotation speed to 300rpm, and the flow rate to 120L / min.

[0092] When the inclination measurement indicated θ = 1.8° (exceeding the threshold of 0.3°), the drilling pressure was reduced to 12 kN, the rotation speed was increased to 450 rpm, and the high-frequency impact device was triggered or activated. Within 5 minutes, θ returned to 1.2°. After re-measurement with the borehole inclinometer, the average curvature of the entire hole was 0.5° / 100m, and the wear of the composite plate was ≤0.2mm, meeting the design requirements.

[0093] When three consecutive inclinometer measurements showed an increase in the θ deviation (2.1° → 2.4° → 2.7°), the inclinometer detected a worsening trend → the data was transmitted in real time to the ground control system, and the ground control system's prediction model calculated the optimal parameters.

[0094] When drilling for water exploration and drainage, fault zones are often encountered, and sudden changes in the formation can easily cause sudden deviation. This triggers the "Emergency Correction Mode"—when the instantaneous rate of change of θ exceeds 3° / 10m, the rotation speed is automatically reduced to 40 rpm and the maximum drilling pressure is applied.

[0095] The downhole drilling correction method for water exploration and drainage, provided by this invention, enables real-time adjustment of the drill tool's posture, improving drilling trajectory control accuracy. Dynamic parameter control reduces the drilling trajectory curvature to ≤0.8° / 100m, enhancing correction accuracy and significantly improving performance compared to traditional methods (≥2° / 100m). Furthermore, it reduces the number of trips required for correction, shortening single-hole construction time by 20-30%, and improving construction efficiency.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A bottom hole assembly, characterized in that: include: Drill rods and drill bits; A centralizer assembly is located between the drill pipe and the drill bit, and the centralizer assembly includes: A centralizer body, the outer surface of which is provided with a plurality of ridges along the axial direction, the ridges being evenly distributed along the circumference of the centralizer body, the top outer edges of the ridges jointly defining a virtual circumscribed circle; the centralizer body having a first end and a second end disposed opposite to each other; a first wear-resistant component, provided at a first end of the centralizer body and connected to the drill bit; a second wear-resistant component, provided at the second end of the centralizer body and connected to the drill pipe; Wherein, the diameters of the first wear-resistant component and the second wear-resistant component are both greater than or equal to the diameter of the circumscribed circle, and the diameters of the first wear-resistant component and the second wear-resistant component are both smaller than the diameter of the drill bit.

2. The bottom hole assembly according to claim 1, wherein: A plurality of first wear-resistant composite sheets are fixedly embedded on the surface of the first wear-resistant component, wherein at least three first wear-resistant composite sheets form a group, each group is arranged at intervals along the axial direction of the first wear-resistant component, and the first wear-resistant composite sheets in each group are evenly distributed in the circumferential direction of the first wear-resistant component; and / or, A plurality of second wear-resistant composite sheets are fixedly embedded on the surface of the second wear-resistant component, and at least three second wear-resistant composite sheets form a group. Each group is arranged at intervals along the axial direction of the second wear-resistant component, and the second wear-resistant composite sheets in each group are evenly distributed in the circumferential direction of the second wear-resistant component.

3. The bottom hole assembly according to claim 2, wherein: On the first wear-resistant component, the arrangement density of the first wear-resistant composite sheets decreases from a position close to the drill bit to a position far away from the drill bit.

4. The bottom hole assembly according to claim 2, wherein: In a group of at least three first wear-resistant composite sheets, the circumferential angle between two adjacent first wear-resistant composite sheets is 120°; and / or, In a group of at least three second wear-resistant composite sheets, the circumferential angle between two adjacent second wear-resistant composite sheets is 120°.

5. The bottom hole assembly according to claim 2, wherein: The first wear-resistant composite sheet and the second wear-resistant composite sheet are both made of tungsten carbide, diamond composite sheet or cubic boron nitride.

6. The bottom hole assembly according to claim 1, wherein: The difference between the diameter of the first wear-resistant component and the diameter of the circumscribed circle ranges from 0.3 mm to 0.5 mm; And / or, the difference between the diameter of the second wear-resistant component and the diameter of the circumscribed circle is in a range of 0.3 mm to 0.5 mm.

7. The bottom hole assembly according to any one of claims 1 to 6, characterized in that: A plurality of first slag discharge grooves are provided on the surface of the first wear-resistant component along the axial direction, and the plurality of first slag discharge grooves are evenly distributed in the circumferential direction of the first wear-resistant component; and / or, A plurality of second slag discharge grooves are provided on the surface of the second wear-resistant component along the axial direction, and the plurality of second slag discharge grooves are evenly distributed in the circumferential direction of the second wear-resistant component.

8. A downhole water exploration and drainage drilling correction system, characterized in that: A bottom hole assembly according to any one of claims 1 to 7, and comprising: Ground control systems; a top drive system connected to the ground control system for adjusting the rotational speed and torque; an automatic drill feed system connected to the ground control system for adjusting the drilling pressure; a mud pump connected to the ground control system for regulating flow; The bottom hole assembly is connected to the top drive system, the automatic drill feed system and the mud pump respectively. The bottom hole assembly is provided with a while drilling inclinometer and a high-frequency impact device. The while drilling inclinometer and the high-frequency impact device are connected to the ground control system.

9. A method for correcting the deviation of a downhole drilling hole for exploration and release of water, which is controlled by the downhole drilling hole correction system for exploration and release of water according to claim 8, characterized in that: The steps include: Obtain the inclination and azimuth of the borehole in real time; When the inclination angle is determined to be greater than or equal to the preset threshold, the drilling pressure and rotation speed are adjusted, and the inclination and azimuth of the borehole are continuously monitored within the target test section; When the deviation of the inclination angle increases for a preset number of consecutive times, automatic correction is triggered: the mud pump flow is controlled to change the hydraulic load of the drill tool, inducing the drill bit to cut sideways; the high-frequency short-stroke impact device is simultaneously started to enhance the active correction ability of the centralizer on the hole wall.

10. The method for correcting the deviation of underground water exploration and drainage drilling according to claim 9, characterized in that: When the inclination angle is determined to be greater than or equal to a preset threshold, adjusting the drilling pressure and the rotation speed includes: Reduce the bit weight to 5-10kN, increase the rotation speed to 400-500rpm, and use the centrifugal force of the centralizer to suppress the upward tilt trend; Alternatively, increase the bit weight to 20-25kN and reduce the rotation speed to 200-300rpm to strengthen the lateral support force of the centralizer.

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