Large-angle curve guiding continuous coring drill bit for superhard formation

Abstract

The invention belongs to the field of geological drilling tools, and particularly discloses a super-hard formation large-angle curve guiding continuous coring drill bit which comprises a drill bit body, and a cutting part of the drill bit body comprises a first cutting part and a second cutting part which are arranged around the end of the drill bit body. The first cutting part and the second cutting part are continuously arranged from inside to outside in the radial direction of the drill bit body; the first cutting part is provided with an arc-shaped cutting edge which protrudes towards the outer side along the end part of the drill bit body; the second cutting part is provided with more than three tooth-shaped cutting edges which are arranged in the radial direction of the drill bit body, and the distance between the outer end part of each tooth-shaped cutting edge and the connecting part is gradually reduced from inside to outside in the radial direction of the drill bit body; and the distance between the outer end part of the innermost tooth-shaped cutting edge and the connecting part is smaller than the distance between the outer end part of the arc-shaped cutting edge and the connecting part. The drill bit has better guidance quality, and the problem that the drill bit deviates from a path in the curve directional coring drilling process is solved.

Description

Technical Field

[0001] The invention relates to the technical field of geological drilling tools, in particular to a large-angle curve-guided continuous coring drill bit for superhard formations. Background Art

[0002] At present, for exploration drilling in areas with high altitudes and large drop in height, especially at the bottom of deep river valleys of the thousand-meter level, it is extremely difficult to take cores from the riverbed and the opposite mountain, as some large-scale engineering exploration equipment is difficult or even impossible to relocate, and it is difficult to effectively build auxiliary platforms on the river surface. There is no guarantee that the coring trajectory will pass through the designated positions of the riverbed and the opposite mountain one after another.

[0003] The patent document with publication number CN118582180A discloses a large-angle curved directional coring method, which mainly adopts a stabilizer with an outer diameter smaller than the outer diameter of the guide drill bit, and makes the difference between the outer diameter of the coring drill rod and the outer diameter of the guide drill bit greater than 15 mm, so that the stabilizer can be used as a rotating fulcrum during the drilling process. Under the action of gravity of multiple coring drill rods, the guide drill bit can be tilted upward by a certain angle, thereby changing the drilling direction, and changing the original straight borehole with a constant inclination angle into a curved borehole with a changed inclination angle, so as to facilitate passing through a designated area of ​​the riverbed of a kilometer-level river channel.

[0004] However, when drilling using the above method, the predetermined drilling route is a curved path that bends upward (bends toward the side of the river valley). However, during the actual drilling process, the drilling route often deviates from the predetermined route to a certain extent, resulting in failure to accurately reach the designated location. Summary of the invention

[0005] The purpose of the present invention is to provide a large-angle curve-guided continuous coring drill bit for ultra-hard formations in response to the problem of deviation in the drilling route in the prior art. The drill bit can utilize the guidance of the drill bit to guide the rear-end drill tool to maintain a predetermined direction, thereby solving the problem of conventional drill bits deviating from the predetermined route under this coring method.

[0006] The present invention is achieved through the following technical solutions: A high-angle curved guide continuous coring drill bit for superhard formations comprises a drill bit body of a hollow cylindrical structure, a cutting portion is arranged at one end of the drill bit body, and a connecting portion is arranged at the other end, the cutting portion comprises a first cutting portion and a second cutting portion respectively arranged around the end of the drill bit body, and the first cutting portion and the second cutting portion are continuously arranged from the inside to the outside along the radial direction of the drill bit body; The first cutting portion has an arc-shaped cutting edge protruding outward along the end of the drill body; The second cutting portion has more than three tooth-shaped cutting edges arranged along the radial direction of the drill body, and the distance between the outer end of the tooth-shaped cutting edge and the connecting portion gradually decreases from the inside to the outside along the radial direction of the drill body; The distance between the outer end of the innermost tooth-shaped cutting edge and the connecting portion is smaller than the distance between the outer end of the arc-shaped cutting edge and the connecting portion.

[0007] Optionally, the maximum thickness of the cutting portion accounts for 50%-55% of the radius of the drill body in the radial direction.

[0008] Optionally, the outer diameter of the cutting portion is 99 mm, and the middle diameter of the cutting portion is 47.5 mm.

[0009] Optionally, the radial thickness of the arc-shaped cutting edge is 13.75 mm, and the radial thickness of each toothed cutting edge is 4 mm.

[0010] Optionally, the toothed cutting edge adopts a right-angle step structure in which one side surface is perpendicular to the radial direction of the drill body and the other side surface is perpendicular to the axial direction of the drill body.

[0011] Optionally, the cutting portion is provided with a plurality of first concave water grooves connecting the inner side of the drill body and the outer side of the drill body along its circumferential direction.

[0012] Optionally, a reinforcement layer is provided in the first recessed water tank, and both sides of the reinforcement layer cover the root of the cutting portion.

[0013] Optionally, the reinforcement layer is made of cemented carbide material.

[0014] Optionally, the second cutting portion is provided with a plurality of second recessed water grooves along its circumferential direction for dividing the second cutting portion, and one end of the second recessed water groove is located outside the first cutting portion and the other end extends to the outside of the drill body.

[0015] Optionally, the second cutting portion includes 3-5 toothed cutting edges, and the distance between the outer ends of the toothed cutting edges and the connecting portion is arranged in an arithmetic progression.

[0016] The technical solution of the present invention has at least the following beneficial effects: The ultra-hard formation large-angle curve-guided continuous coring drill bit of the present invention is provided with a first cutting part and a second cutting part. The first cutting part adopts an arc-shaped cutting edge and the second cutting part adopts a multi-tooth cutting edge structure, and the number of cutting edges and the axial distance size are strictly controlled, so that the entire cutting part can form a conical structure. The drill bit with a conical structure can control the direction well during the drilling process of the curved path, so that it has better guidance and avoids the drill bit from deviating from the route during drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a large-angle curve-guided continuous coring drill bit for superhard formations of the present invention; Figure 2 It is a cross-sectional view of the ultra-hard formation large-angle curve-guided continuous coring drill bit of the present invention; Figure 3 It is a schematic end view of the large-angle curve-guided continuous coring drill bit for superhard formations of the present invention; Figure 4 The core obtained by the ultra-hard formation large-angle curve-guided continuous coring drill bit of the present invention Figure 1 ; Figure 5 The core obtained by the ultra-hard formation large-angle curve-guided continuous coring drill bit of the present invention Figure 2 .

[0018] Figure numerals: 100 - drill body, 110 - cutting part, 111 - first cutting part, 112 - second cutting part, 121 - first recessed water groove, 122 - second recessed water groove, 130 - reinforcement layer, 140 - connection part. DETAILED DESCRIPTION

[0019] The ultra-hard formation large-angle curve-guided continuous coring drill bit of the present invention is used for the process of large-angle curve directional coring of the drill tool. Since the overall drilling route is a curved path that bends upward (bends toward the river valley), to achieve the drilling of the above path, the stabilizer in the drill tool needs to be able to serve as a rotating fulcrum to control the entire drilling trajectory to tilt upward, and it is necessary to ensure that the drill bit contacts the rock formation on one side of its upper side to achieve the overall curved path drilling. However, the conventional drill bit structure generally has a planar structure or a roughly planar structure at its end. Because conventional drill bits are used for linear drilling of horizontal holes, vertical holes or inclined holes, the drill bits are all planar structures and can use the characteristics of force balance to achieve linear drilling. However, when this type of planar drill bit is used in the process of drilling a curved path, due to factors such as gravity, curved paths, and control methods, the lower half of the planar drill bit is more likely to combine or contact with the rock formation. Under such an unbalanced force condition, the relationship between the action and reaction forces between the lower half and the rock formation causes the entire drill bit to be "attracted" to tilt to the side below the drilling route, causing the entire drill bit to deviate from the established route.

[0020] Therefore, in view of the above situation, refer to Figure 1-Figure 5The present invention provides a large-angle curve-guided continuous coring drill bit for superhard formations, including a drill bit body 100 with a hollow cylindrical structure for coring. A cutting portion 110 is provided at one end of the drill bit body 100, and the cutting portion 110 is used for rotationally cutting rock formations. A connecting portion 140 is provided at the other end, and the connecting portion 140 is used to connect other components of the drilling tool, such as a reamer. The cutting portion 110 includes a first cutting portion 111 and a second cutting portion 112 respectively arranged around the end of the drill bit body 100, and the first cutting portion 111 and the second cutting portion 112 are continuously arranged from the inside to the outside along the radial direction of the drill bit body 100. Among them, the first cutting portion 111 has an arc-shaped cutting edge protruding outward along the end of the drill bit body 100; the second cutting portion 112 has more than three toothed cutting edges arranged along the radial direction of the drill bit body 100, and the distance between the outer end of the toothed cutting edge and the connecting portion 140 gradually decreases from the inside to the outside along the radial direction of the drill bit body 100 (such as Figure 2 As shown, L1, L2 and L3 represent the distances between the outer ends of the three toothed cutting edges and the connecting portion 140 respectively); the distance between the outer end of the innermost toothed cutting edge and the connecting portion 140 is smaller than the distance between the outer end of the arc-shaped cutting edge and the connecting portion 140 (as shown in FIG. Figure 2 As shown, L4 represents the distance between the outer end of the arc-shaped cutting edge and the connecting portion 140). The present invention adopts an arc-shaped cutting edge at the end of the drill bit body 100 to bear the main cutting torque of the middle area except the core, and forms densely distributed small cutting edges through more than three tooth-shaped cutting edges around. At the same time, by controlling the distance between the cutting edge and the connecting portion 140, a conical structure with a protrusion in the middle and a gradually inclined periphery is formed. The advantage of this conical structure is that during the drilling process, due to the small diameter of its front end, when it contacts the rock formation, the situation that the lower area contacts more and is subjected to greater force than the upper area due to factors such as gravity will not occur, and the drilling direction is easier to control. At the same time, more than three toothed cutting edges and the overall inclined structural arrangement reduce the contact area of ​​the drill bit end on the same plane compared to a drill bit with a planar structure, or in other words, the contact surface is converted to different radial planes, which further disperses the torque. This can improve problems such as insufficient torque or drill sticking during core drilling in ultra-hard formations. It is also suitable for solving the problem of incompatibility between a planar drill bit with planar distributed torque and a curved path during curved drilling.

[0021] Furthermore, the toothed cutting edge adopts a right-angle step structure in which one side is perpendicular to the radial direction of the drill bit body 100 and the other side is perpendicular to the axial direction of the drill bit body 100. Such a right-angle step structure can provide a more uniform force distribution and ensure sufficient strength to cope with ultra-hard geological rock formations on the side in contact with the rock formation. The second cutting portion 112 preferably includes 3-5 toothed cutting edges, and the distance between the outer end of the toothed cutting edge and the connecting portion 140 is arranged in an arithmetic progression. By selecting the configuration number of 3-5 toothed cutting edges, the transition will be more uniform and the resistance will be small. The overall conical structure formed by 3-5 toothed cutting edges and 1 arc-shaped cutting edge cooperates with the flexible drill rod to form a structure similar to a cannonball, and has a strong drilling ability. Because the toothed cutting edge is a small step structure, the overall conical profile formed is uniform and has low resistance. If two toothed cutting edges are selected, the tooth shape is larger, the step transition formed is larger, and the damping change is also larger; when the number exceeds 5, the step is not obvious. During the drilling process, each toothed cutting edge cannot bear much torque, the drilling ability is improved, but the cutting ability is compromised, and it is difficult to apply to ultra-hard geological structures.

[0022] At the same time, the ultra-hard formation large-angle curve guided continuous coring drill bit of the present invention is used for guided coring of flexible curves. The drill tool or drill rod used for such coring needs to swing to adjust the angle. Therefore, the drill tool or drill rod is a small-diameter structure, so as to maintain a gap with the borehole to complete the angle adjustment. The middle of the drill body 100 of the present invention also adopts a small-diameter structure. Specifically, the maximum thickness a of the cutting part 110 accounts for 50%-55% of the radius r of the drill body 100 in the radial direction. Conventional coring drill bits will be designed with a relatively large middle diameter. The large middle diameter leaves limited design space for the cutting part 110. Therefore, in conventional drill bits, it is difficult to have enough space to design a cutting part 110 structure having a first cutting part 111 and a multi-step second cutting part 112.

[0023] This embodiment provides a specific design size. The outer diameter of the cutting part 110 is 99 mm, and the middle diameter of the cutting part 110 is 47.5 mm. The radial thickness of the arc-shaped cutting edge is 13.75 mm, and the radial thickness of each tooth-shaped cutting edge is 4 mm. Through such a size design, large-angle curve-guided continuous coring in superhard formations is achieved, and curved cores such as Figure 4 , Figure 5 shown.

[0024] The present invention also provides a plurality of first recessed water grooves 121 connecting the inner side of the drill bit body 100 and the outer side of the drill bit body 100 along the circumferential direction of the cutting portion 110. The drilling fluid in the drill rod can be guided to the middle cavity of the drill bit body 100, and then flow to the outer side of the drill bit body 100 through the first recessed water grooves 121. During this flow process, since the first cutting portion 111 of the present invention adopts an arc-shaped cutting edge, there are gaps on both sides of the arch. The drilling fluid in the middle cavity and the drilling fluid in the first recessed water grooves 121 can easily reach both sides of the arch to lubricate and cool the cutting process of the first cutting portion 111. The second cutting portion 112 adopts a plurality of toothed cutting edges with varying heights. When the drilling fluid passes through the position where the second cutting portion 112 is located, it can also easily flow into each toothed cutting edge through the gap between the corner of each step and the rock formation to lubricate and cool the toothed cutting edge. Since the number of toothed cutting edges in the present invention is large and the height difference is not large, the fluidity of the drilling fluid cannot achieve an ideal effect. Therefore, a plurality of second recessed water grooves 122 are arranged along the circumferential direction of the second cutting portion 112 to divide the second cutting portion 112. One end of the second recessed water groove 122 is located outside the first cutting portion 111, and the other end extends to the outside of the drill bit body 100. On the one hand, the second recessed water groove 122 can be filled with the drilling fluid refluxed from the outside of the drill bit body 100, and on the other hand, the toothed cutting edge with better fluidity can also be filled with the second recessed water groove 122 through circumferential flow, and then the cutting blood in the second recessed water groove 122 can be used to fill and compensate for the position of the toothed cutting edge with poor fluidity, thereby ensuring that the entire annular toothed cutting edge is filled with drilling fluid.

[0025] Since the first sunken water tank 121 is the main drilling fluid circulation path, the depth and width are relatively deep, so a reinforcement layer 130 is provided in the first sunken water tank 121. The reinforcement layer 130 is preferably made of a cemented carbide material, and the two sides of the reinforcement layer 130 cover the root of the cutting part 110. The reinforcement of the two sides of the first sunken water tank 121 by the reinforcement layer 130 ensures the structural strength of the cutting part 110 at its root, and can easily cope with the drilling coring of such ultra-hard geology, and can also easily cope with the problem of the cutting part 110 being easily broken due to the uneven force during the drilling of such a curved path.

Claims

1. A large-angle curve-guided continuous coring drill bit for superhard formations, comprising a drill bit body with a hollow cylindrical structure, one end of the drill bit body is provided with a cutting portion, and the other end is provided with a connecting portion, characterized in that: The cutting portion comprises a first cutting portion and a second cutting portion respectively arranged around the end of the drill body, and the first cutting portion and the second cutting portion are continuously arranged from inside to outside along the radial direction of the drill body; The first cutting portion has an arc-shaped cutting edge protruding outward along the end of the drill body; The second cutting portion has more than three tooth-shaped cutting edges arranged along the radial direction of the drill body, and the distance between the outer end of the tooth-shaped cutting edge and the connecting portion gradually decreases from the inside to the outside along the radial direction of the drill body; The distance between the outer end of the innermost tooth-shaped cutting edge and the connecting portion is smaller than the distance between the outer end of the arc-shaped cutting edge and the connecting portion.

2. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 1, characterized in that: The maximum thickness of the cutting portion accounts for 50%-55% of the radius of the drill body in the radial direction.

3. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 2, characterized in that: The outer diameter of the cutting part is 99 mm, and the middle diameter of the cutting part is 47.5 mm.

4. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 2, characterized in that: The radial thickness of the arc-shaped cutting edge is 13.75 mm, and the radial thickness of each tooth-shaped cutting edge is 4 mm.

5. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 1, characterized in that: The toothed cutting edge adopts a right-angle step structure in which one side surface is perpendicular to the radial direction of the drill body and the other side surface is perpendicular to the axial direction of the drill body.

6. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 1, characterized in that: The cutting portion is provided with a plurality of first concave water grooves connecting the inner side of the drill body and the outer side of the drill body along the circumferential direction thereof.

7. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 6, characterized in that: A reinforcement layer is arranged in the first concave water tank, and both sides of the reinforcement layer cover the root of the cutting part.

8. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 7, characterized in that: The reinforcement layer is made of hard alloy material.

9. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 1 or 6, characterized in that: The second cutting portion is provided with a plurality of second concave water grooves along its circumferential direction for dividing the second cutting portion, one end of the second concave water groove is located outside the first cutting portion, and the other end extends to the outside of the drill body.

10. The ultra-hard formation large-angle curve-guided continuous coring drill bit according to claim 1, characterized in that: The second cutting portion includes 3-5 toothed cutting edges, and the distance between the outer ends of the toothed cutting edges and the connecting portion is arranged in an arithmetic progression.

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