A coring drill suitable for hard and broken formations

Abstract

A coring drill tool suitable for hard and broken formations: the coring drill tool comprises a coring drill bit, a drill rod, an outer tube, an inner tube, a straightening block and a supporting part; the upper part of the outer tube is connected to the drill rod, and the lower part is connected to the coring drill bit; a straightening block is arranged on the inner wall of the lower side of the outer tube; a supporting part is arranged between the inner tube and the outer tube; the inner tube is composed of a plurality of tubes, and the tubes are connected by threads; a plurality of axially symmetrical grooves are evenly distributed on the inner wall of the tube, and a locking core mechanism is arranged on the groove; the locking core mechanism comprises a rebound member, an axial hole and a locking core plate; the rebound member is arranged on the groove; the locking core plate is connected to the rebound member through the axial hole; the locking core plate is in the shape of a fan, and axial holes are arranged at both ends of the outer edge of the fan, the part of the fan close to the center of the circle is arc-shaped, and tooth-like fangs are arranged on the arc edge; the number of the locking core plates is multiple, and the locking core plates are spliced ​​into a locking core ring with a component structure; the present invention can significantly improve the success rate of coring in broken formations, improve the efficiency of coring in drilling, and reduce the cost of coring.

Description

Technical Field

[0001] The invention relates to the technical field of geological exploration, in particular to a drilling device suitable for hard and broken strata. Background Art

[0002] While the reserves of traditional energy are decreasing, environmental problems are becoming more acute. Countries have begun to exploit new energy sources, including solar energy, geothermal energy, wind energy, biomass energy and other new energy sources. As a clean renewable energy source, hot dry rock is the most promising part of geothermal energy and the future of geothermal energy. In terms of distribution, hot dry rock resources, like shallow geothermal energy, are widely distributed resources. However, compared with shallow geothermal energy, hot dry rock is less affected by external conditions such as climate. In terms of resource quality, hot dry rock resources are mainly used for power generation, which can solve the fundamental energy needs of the country and have a larger resource base. Therefore, hot dry rock is also called a new energy source that may change the future. Hot dry rock power generation is a long-term goal of geothermal energy utilization in my country. At present, the main method of utilizing hot dry rock resources is to drill an injection well into the hot dry rock on the surface, seal the wellbore and inject low-temperature water into the well at high pressure. The low-temperature water evaporates into water vapor after being heated by the high-temperature hot dry rock, and then uses high-pressure water vapor to generate electricity. In order to ensure the smooth progress of drilling, fracturing and production during the mining process, it is necessary to carry out coring operations for well sections of different depths to analyze the development of rock fractures in the target layer. The current coring tools usually pull the core out of the formation by clamping the core. For harder formations, this coring tool is very practical and has a high coring success rate. However, for shallow soft formations, undiagenetic formations and broken formations, the coring success rate of this coring tool is low, and coring may even fail. Failure of coring operations will lead to the loss of geological data and the inability to directly and objectively understand the underground situation, resulting in slow progress of engineering operations and lack of formation information, increasing the cost of drilling operations and affecting geological understanding. Therefore, it is urgent to design a simple, economical, reliable and convenient drill tool suitable for coring hard and broken formations based on the actual operational difficulties. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a coring drill suitable for hard and broken formations. The present invention is not only suitable for coring operations in ordinary formations, but also for coring operations in broken formations, and can significantly improve the coring success rate and greatly reduce the cost of coring operations.

[0004] The problem described in the present invention is solved by the following technical solutions:

[0005] The coring drill tool according to claim 1, wherein the coring drill tool comprises a coring drill bit, a drill rod, an outer tube, an inner tube, a straightening block and a supporting part; the upper part of the outer tube is connected to the drill rod, and the lower part is connected to the coring drill bit; a straightening block is provided on the inner wall of the lower side of the outer tube; a supporting part is provided between the inner tube and the outer tube; the inner tube is composed of a plurality of tube barrels, and the tube barrels are connected by threads; a plurality of axially symmetrical grooves are evenly distributed on the inner wall of the tube barrel, and a locking core mechanism is provided on the groove; the locking core mechanism comprises a rebound member, an axial hole and a locking core plate; the rebound member is arranged on the groove; the locking core plate is connected to the rebound member through the axial hole; the locking core plate is in the shape of a fan, and axial holes are provided at both ends of the outer edge of the fan, the part of the fan close to the center of the circle is arc-shaped, and toothed fangs are provided on the arc edge; the number of the locking core plates is multiple, and the locking core plates are spliced ​​into a locking core ring of a component structure.

[0006] The above-mentioned coring drill tool is suitable for hard and broken formations, and the rebound part includes a torsion spring, a fixing block and an arc-shaped shaft; the groove includes a lower end face of the groove and a side end face of the groove; the arc-shaped shaft passes through the shaft hole and is inserted into the supporting hole in the side end face of the groove; the torsion spring is sleeved on the arc-shaped shaft, and a clamping block is provided in the middle of the torsion spring, which fixes the torsion spring on the lower end face of the groove, and the two ends of the torsion spring are connected to the upper end face of the lock core plate.

[0007] The above-mentioned coring drill tool is suitable for hard and broken formations, and the supporting part includes a bearing, a limit block, a bearing seat and a bearing seat cover; the inner wall of the bearing seat is interference fit with the outer wall of the bearing outer ring; the inner wall of the bearing inner ring is interference fit with the tube; the bearing seat cover is arranged on the bearing seat; the outer wall of the bearing seat is axially symmetrically provided with limit blocks with the same number as the limit grooves, and the limit blocks cooperate with the limit grooves axially symmetrically provided on the inner wall of the outer tube.

[0008] The above-mentioned coring drill tool is suitable for hard and broken formations. The upper end of the inner tube is an inverted cone structure, and multiple flow channels are symmetrically distributed on the inner wall of the inverted cone structure. The flow channels connect the inner and outer walls of the inner tube; the upper end of the inner tube is provided with a leak-proof ball with a diameter slightly larger than the inner diameter of the inner tube.

[0009] The above-mentioned coring drill tool suitable for hard and broken formations has a plurality of straightening blocks symmetrically arranged along the axial direction at the lower end of the inner wall of the outer tube, and the inner diameter of the straightening hole surrounded by the straightening blocks is slightly larger than the outer diameter of the inner tube; the part where the straightening blocks contact the outer wall of the inner tube is arc-shaped.

[0010] The above-mentioned coring drill tool suitable for hard and broken formations is characterized in that a core seat is provided at the bottom end of the inner tube; the core seat includes a hollow cylinder and a retaining spring; the retaining spring is arranged in the hollow cylinder; the core seat and the inner tube are threadedly connected; the core seat can be moved in the up and down directions by rotating at the lower end of the inner tube; a lock nut is also provided at the lower end of the inner tube; the lock nut is threadedly connected to the inner tube, and the lock nut is arranged above the core seat.

[0011] The present invention effectively improves the success rate of coring in broken formations through a core locking mechanism and a core holder, and avoids the previous failure of coring. The core locking mechanism is arranged in a groove inside the inner tube; when the broken core enters the inner tube, under the action of external force, the core will push the core locking plate to flip upwards, and at this time, the torsion spring undergoes elastic deformation due to the flipping of the core locking plate, so that the torsion spring obtains elastic potential energy. When the core is collected and the drill bit does not continue to drill downward, the core external force disappears, and the elastic potential energy of the torsion spring will drive the core locking plate to flip downwards until it returns to a horizontal state. The core locking plate basically closes the inner tube, and because the core locking plate cannot flip downwards, the broken core above the core locking mechanism cannot move downwards, thereby smoothly bringing the broken core out of the underground; effectively improving the efficiency and success rate of coring, and avoiding the previous situation in which the core falls off the inner tube due to excessive fragmentation of the broken core when the drilling tool is lifted. The core holder can ensure that the complete columnar core does not fall out of the inner tube when the drill bit is lifted and returned to the surface; there is a conical retaining spring inside the core holder. When the core moves downward, the inner diameter of the retaining spring becomes smaller, thereby clamping the core to prevent it from moving further downward, thereby ensuring the smooth progress of the coring operation.

[0012] The present invention is also provided with a supporting part and a straightening block; the supporting part can ensure that the inner tube and the outer tube do not affect each other, that is, the two are in a single-action state; the straightening block straightens the inner tube to prevent the lower part of the inner tube from shaking, thereby affecting the core entering the inner tube.

[0013] In addition, the present invention provides a leak-proof ball and a flow channel on the upper part of the inner tube; the leak-proof ball can block the upper port of the inner tube to prevent the drilling fluid from entering the inner tube, thereby avoiding the drilling fluid from contaminating the core sample; the flow channel connects the inner and outer walls of the inner tube. When the leak-proof ball blocks the upper port of the inner tube, the drilling fluid that should originally flow through the inner tube flows to the gap between the inner and outer tubes through the flow channel, thereby providing a circulation channel for the drilling fluid and ensuring the smooth progress of the drilling operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the cross-sectional structure of the present invention;

[0015] Figure 2 It is a partial enlarged view of A of the present invention;

[0016] Figure 3 It is a schematic diagram of the local structure of the groove of the present invention;

[0017] Figure 4 It is a structural schematic diagram of the lock core mechanism of the present invention;

[0018] Figure 5 It is a structural schematic diagram of the straightening block of the present invention.

[0019] The list of numbers in the figure is: 1. core drill bit, 2. drill rod, 3. outer tube, 4. tube, 5. straightening block, 6. bearing, 7. groove, 7-1. lower end face of groove, 7-2. side end face of groove, 8. locking plate, 9. torsion spring, 10. shaft hole, 11. arc shaft, 12. limit block, 13. limit groove, 14. flow channel, 15. anti-leakage ball, 16. hollow cylinder, 17. retaining ring, 18. bearing seat, 19. bearing seat cover, 20. fixing block, 21. anti-loosening nut. DETAILED DESCRIPTION

[0020] See also Figure 1 , 2 , 3, 4 and Figure 5 The present invention comprises a coring drill bit 1, a drill rod 2, an outer tube 3, an inner tube, a straightening block 5 and a supporting part; the outer tube 3 is connected to the drill rod 2 at the top and to the coring drill bit 1 at the bottom; a straightening block 5 is arranged on the inner wall of the lower side of the outer tube 3; a supporting part is arranged between the inner tube and the outer tube 3; the characteristic is that: the inner tube is composed of a plurality of tubes 4, which are connected by threads, and the inner tube is divided into a plurality of tubes 4, which can make the processing easier to realize and can also facilitate the workers to overhaul the inner tube; a plurality of axially symmetrical grooves 7 are arranged on the inner wall of the tube 4, and a locking core is arranged on the groove 7 Mechanism; the locking core mechanism includes a rebound piece and a locking core plate 8; the locking core plate 8 is connected to the groove 7 through the rebound piece, and the number of the locking core plates 8 is consistent with the number of the grooves 7; the shape of the locking core plate 8 is a fan-shaped, and axial holes are provided at both ends of the outer edge of the fan-shaped, the part of the fan-shaped close to the center of the circle is arc-shaped, and the arc-shaped edge is provided with serrated fangs. When the locking core plate 8 cannot be completely reset, the serrated fang structure of the central angle part can effectively prevent the core from moving downward, greatly improving the success rate of coring; the number of the locking core plates 8 is multiple, and the locking core plates 8 are spliced ​​into a locking core ring with a separate structure.

[0021] In order to prevent the broken core from detaching from the drilling tool during the process of lifting the drilling tool, the present invention is specially provided with a rebound member; the rebound member includes a torsion spring 9, an axial hole 10 and an arc shaft 11; the axial hole 10 is an arc-shaped circular tube, and is arranged at both ends of the arc edge of the locking core plate 8; the center of the arc axis 11 line of the axial hole 10 is concentric with the center of the arc edge of the locking core plate 8; the torsion spring 9 is arranged in the middle of the two axial holes 10 of the locking core plate 8, and the two ends of the torsion spring 9 are connected to the upper end surface of the locking core plate 8, and the middle part of the torsion spring 9 is fixed to the inner wall of the groove 7; When the core enters the inner tube, the core pushes the locking core plate 8 to flip upward into the groove 7. At this time, the torsion spring 9 undergoes elastic deformation as the locking core plate 8 flips, thereby obtaining elastic potential energy. When the core stops moving upward, the torsion spring 9 releases the elastic potential energy it has obtained, driving the locking core plate 8 to flip and reset, thereby realizing the function of closing the inner tube; the arc shaft 11 passes through the two axial holes 10 of the locking core plate 8, and also passes through the torsion spring 9 between the locking core plates 8, and the two ends of the arc shaft 11 are connected to the inner wall of the groove 7.

[0022] In order to avoid mutual influence between the inner tube and the outer tube 3, the present invention is provided with a supporting part; the supporting part includes a bearing 6, a stopper 12, a bearing seat 18 and a bearing seat cover 19; the inner wall of the bearing seat 18 is interference fit with the outer wall of the outer ring of the bearing 6; the inner wall of the inner ring of the bearing 6 is interference fit with the tube 4; the bearing seat cover 19 is arranged on the bearing seat 18; the outer wall of the bearing seat 18 is axially symmetrically provided with stoppers 12 with the same number as the stopper grooves 13, and the stoppers 12 are axially symmetrical with the inner wall of the outer tube 3. The limit grooves 13 are arranged to cooperate with each other, and the limit grooves 13 extend along the axial direction of the outer tube 3. When the supporting part is installed, the limit block 12 on the bearing seat 18 can slide into place from top to bottom along the limit grooves 13; the outer tube 3 cooperates with the limit block 12 on the supporting part through the limit grooves 13, so that the outer tube 3 does not affect the inner ring of the bearing 6 when rotating, thereby ensuring that the inner tube that is interference-fitted with the inner ring of the bearing 6 remains in a relatively static state, thereby avoiding the accident of core fracture caused by the rotation of the inner tube.

[0023] During the drilling process, drilling fluid will be injected into the drill bit. In order to prevent the drilling fluid from damaging the core sample, the present invention is provided with a flow channel 14 and a leak-proof ball 15; the upper end of the inner tube is an inverted cone structure, which is used to cooperate with the leak-proof ball 15 to block the upper port of the inner tube; a plurality of flow channels 14 are symmetrically distributed on the inner wall of the inverted cone structure, and the flow channels 14 connect the inner and outer walls of the inner tube; the diameter of the leak-proof ball 15 is larger than the inner diameter of the inner tube; when the inner tube is blocked by the leak-proof ball 15, the drilling fluid that should originally flow through the inner tube will enter the gap between the inner tube and the outer tube 3 through the flow channel 14, thereby avoiding the drilling fluid from contaminating the core.

[0024] In order to prevent the inner tube from shaking randomly during the drilling operation, the present invention is provided with a straightening block 5; the straightening block 5 is symmetrically arranged at the lower end of the inner wall of the outer tube 3 along the axial direction, and the inner diameter of the straightening hole surrounded by the straightening block 5 is slightly larger than the outer diameter of the inner tube; the contact portion between the straightening block 5 and the outer wall of the inner tube is arc-shaped; the area surrounded by the straightening block 5 has a limiting effect on the inner tube, preventing the lower end of the inner tube from shaking around; there is a gap between the straightening blocks 5, which ensures that the drilling fluid can flow smoothly to the drill bit.

[0025] In order to prevent the complete columnar core from detaching from the bottom of the inner tube, the present invention is provided with a core holder; the core holder is arranged at the bottom end of the inner tube; the core holder includes a hollow cylinder 16 and a retaining spring 17; the retaining spring 17 is arranged in the hollow cylinder 16; when the core enters the inner tube and enters the core holder, the retaining spring 17 moves upward to a certain position, and when the drilling tool is brought back to the surface, the core moves downward under the action of its own gravity, which also drives the retaining spring 17 to move downward, and because the retaining spring 17 is a non-closed retaining spring 17 and is conical, the core is driven to move downward when the retaining spring 17 is driven downward. During the operation, the inner diameter of the retaining spring 17 will be further reduced, thereby limiting the further downward movement of the core and achieving the purpose of bringing the core back to the surface. During the operation of the conventional coring drill, it is necessary not only to consider the erosion of the core in the inner tube by the drilling fluid in the upper drill pipe 2 of the coring drill, but also to consider the reverse erosion of the drilling fluid flowing through the outer tube 3 of the drill and the annulus of the inner tube to the inner bottom end face of the coring drill bit 1. When the gap between the inner tube and the inner end face of the coring drill bit 1 is too large or too small, the drilling fluid may be reversely eroded. The situation is that the drilling fluid flows back to the inside of the inner tube and erodes the core in the tube. Therefore, before the on-site operation, the gap between the inner tube and the inner end face of the coring drill bit 1 needs to be adjusted to a reasonable range; at present, conventional coring drills generally require manual adjustment of the mandrel at the end of the drill to drive the inner tube of the coring drill to rotate so as to adjust the gap between it and the inner end face of the coring drill bit 1, but this method is laborious and time-consuming, while the present invention only needs to adjust the gap between the retaining spring seat and the coring drill bit 1 to achieve the purpose of adjusting the gap between the inner tube and the inner end face of the coring drill bit 1; the retaining spring seat and the inner tube are threadedly connected, Therefore, the card core seat can be moved up and down on the inner tube by rotating, thereby realizing the function of adjusting the gap. In addition, in order to stabilize the card core seat in a set position, the present invention is also provided with a lock nut 21, which is arranged at the lower end of the inner tube through a threaded connection, and its lower end face is in close contact with the upper end face of the card core seat. When the card core seat is rotated to the set position, the locking nut 21 is screwed toward the card core seat to make it in close contact, thereby clamping the position of the card core seat, thereby avoiding the position of the card core seat changing during the drilling operation and affecting the operation.

[0026] A coring tool suitable for use in hard and broken formations is carried out in the following manner:

[0027] (1) Under a certain drilling pressure, the coring drill bit 1 connected to the lower part of the outer tube 3 drills into the formation, and the core gradually enters the core holder and the inner tube;

[0028] (2) When the core reaches the locking mechanism, the core will push the locking plate 8 to flip upward, and at the same time, the torsion spring 9 obtains elastic potential energy due to elastic deformation;

[0029] (3) When the drilling tool no longer moves downward, the locking plate 8 flips back to its original position under the action of the elastic potential energy of the torsion spring 9. At this time, the locking mechanism basically closes the downward passage of the inner tube, and the core at the upper end of the locking mechanism cannot move downward;

[0030] (4) For the core holder at the bottom of the outer tube 3, if the core at the bottom is relatively intact, the retaining spring 17 of the core holder will prevent the core at the bottom from moving downward;

[0031] (5) After the drilling tool is lifted out of the ground, the inner tube is lifted out from the upper end of the outer tube 3, and then the inner tube is inverted. At this time, the core locking mechanism is turned over under the action of the core gravity above it, so that the core can be smoothly withdrawn from the inner tube.

Claims

1. A coring drill tool suitable for hard and broken formations: the coring drill tool comprises a coring drill bit (1), a drill rod (2), an outer tube (3), an inner tube, a straightening block (5) and a supporting part; the outer tube (3) is connected to the drill rod (2) at the top and to the coring drill bit (1) at the bottom; a straightening block (5) is provided on the inner wall of the lower side of the outer tube (3); a supporting part is provided between the inner tube and the outer tube (3); the characteristics are: The inner tube is composed of a plurality of tubes (4), and the tubes (4) are connected by threads; a plurality of axially symmetrical grooves (7) are evenly distributed on the inner wall of the tube (4), and a locking core mechanism is provided on the groove (7); the locking core mechanism comprises a resilient member, an axial hole (10) and a locking core plate (8); the resilient member is arranged on the groove (7); the locking core plate (8) is connected to the resilient member through the axial hole (10); the locking core plate (8) is in the shape of a sector, and the axial holes (10) are provided at both ends of the outer edge of the sector, the part of the sector close to the center is arc-shaped, and the arc-shaped edge is provided with tooth-like fangs; the number of the locking core plates (8) is multiple, and the locking core plates (8) are spliced ​​into a locking core ring of a component structure; A card seat is provided at the bottom end of the inner tube; the card seat comprises a hollow cylinder (16) and a retaining spring (17); the retaining spring (17) is arranged in the hollow cylinder (16); the card seat and the inner tube are threadedly connected; the card seat can be moved in the up and down directions by rotating at the lower end of the inner tube; a locking nut (21) is also provided at the lower end of the inner tube; the locking nut (21) is threadedly connected to the inner tube, and the locking nut (21) is arranged above the card seat; A conical retaining spring is arranged inside the core holder. When the core moves downward, the inner diameter of the retaining spring becomes smaller, thereby clamping the core.

2. The coring drill tool suitable for hard and broken formations according to claim 1, characterized in that: The resilient member comprises a torsion spring (9), a fixing block (20) and an arc-shaped shaft (11); the groove (7) comprises a groove lower end surface (7-1) and a groove side end surface (7-2); the arc-shaped shaft (11) passes through the shaft hole (10) and is inserted into a supporting hole in the groove side end surface (7-2); the torsion spring (9) is sleeved on the arc-shaped shaft (11), a fixing block (20) is provided in the middle of the torsion spring (9), and the fixing block (20) fixes the torsion spring (9) on the groove lower end surface (7-1), and two ends of the torsion spring (9) are connected to the upper end surface of the lock core plate (8).

3. The coring drill tool suitable for hard and broken formations according to claim 2, characterized in that: The supporting part comprises a bearing (6), a limiting block (12), a bearing seat (18) and a bearing seat cover (19); the inner wall of the bearing seat (18) is interference fit with the outer wall of the outer ring of the bearing (6); the inner wall of the inner ring of the bearing (6) is interference fit with the tube (4); the bearing seat cover (19) is arranged on the bearing seat (18); the outer wall of the bearing seat (18) is axially symmetrically provided with limiting blocks (12) having the same number as the limiting grooves (13), and the limiting blocks (12) and the limiting grooves (13) axially symmetrically provided on the inner wall of the outer tube (3) cooperate with each other.

4. The coring drill tool suitable for hard and broken formations according to claim 3, characterized in that: The upper end of the inner tube is an inverted cone structure, and a plurality of flow channels are symmetrically distributed on the inner wall of the inverted cone structure, and the flow channels connect the inner and outer walls of the inner tube; the upper end of the inner tube is provided with a leak-proof ball (15) with a diameter slightly larger than the inner diameter of the inner tube.

5. The coring drill tool suitable for hard and broken formations according to claim 4, characterized in that: A plurality of straightening blocks (5) are symmetrically arranged along the axial direction at the lower end of the inner wall of the outer tube (3), and the inner diameter of the straightening hole surrounded by the straightening blocks (5) is slightly larger than the outer diameter of the inner tube; the portion where the straightening blocks (5) contact the outer wall of the inner tube is arc-shaped.

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