Hydraulically driven automatic corer

Abstract

This invention designs a hydraulically driven automatic core extractor, comprising an inner ring drill bit, an outer ring drill bit, a lower casing, a connecting pipe, an upper casing, and a core tube. The outer ring drill bit is nested with the lower part of the inner ring drill bit via a bevel gear. The inner and outer ring gears rotate in opposite directions, simultaneously cutting the formation. The upper part of the inner ring gear nests with the lower casing to form an axial piston hydraulic motor structure, driven by drilling fluid pressure. The top surface of the lower casing connects to the connecting pipe, allowing for preset core cutting lengths by connecting pipes of different lengths. The other end of the connecting pipe connects to the upper casing, which controls the core cutting edge to cut the core when the core reaches the predetermined length. This invention mitigates the impact on the core through the counter-rotating cutting of the inner and outer ring drill bits, improving the core integrity rate. Furthermore, the use of wireline coring and downhole power enhances coring efficiency and expands its applicability.

Description

Technical Field

[0001] This invention relates to a core extractor, and more particularly to a hydraulically driven automatic core extractor. Background Technology

[0002] Core samples are the most complete and direct stratigraphic and geological data obtainable during oil exploration and development. Oilfield development plans, oil and gas reserve calculations, and oilfield production enhancement measures all rely on core analysis and research. Core recovery rate and integrity are of great significance to petroleum engineering. In traditional coring operations, the interaction and trajectory between the coring drill bit and the wellbore during rotary drilling resemble an internal planetary gear mechanism. This gyratory phenomenon continuously impacts the extracted core, compromising its integrity. Furthermore, traditional core extraction methods are inefficient and yield low core recovery rates. In addition, with the increasing difficulty of oil extraction and the growing application of advanced drilling techniques such as horizontal wells, branch wells, and underbalanced drilling, traditional top-drive coring technology is ill-suited to these advanced technologies. Therefore, designing a hydraulically driven automatic coring device that minimizes core impact, utilizes wireline coring, and incorporates downhole hydraulic power is crucial to address these issues. Summary of the Invention

[0003] In order to improve the integrity and recovery rate of core samples, increase coring efficiency, better adapt to advanced drilling technology, and overcome the shortcomings of existing technologies, the purpose of this invention is to solve some technical problems: to provide a hydraulically driven automatic coring device that has low impact on core samples, high coring efficiency, and wide applicability.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: This core extractor includes an upper shell, a connecting pipe, a lower shell, an inner ring drill bit, a hydraulic rod, an outer ring drill bit, a core tube, a positioning valve, an upper spring, a core tube locking pin, a right one-way valve, a lower spring, a bevel gear, bearing balls, a cutting edge, a retaining ring, a support ridge, a drill bit blade, a water eye, a connecting column, an annular groove, a cut-off inlet pipe, a left guide groove, a drill inlet / outlet pipe, a drill inlet / outlet pipe, a right guide groove, a cut-off outlet pipe, a source inlet pipe, a left arc-shaped groove, a right arc-shaped groove, a tail ridge, a sliding groove, a limiting key, a limiting groove, a locking pipe, an inclined rail, a locking annular groove, and a left one-way valve. The core tube is a circular tube structure. The upper shell, connecting pipe, lower shell, and inner ring drill bit are all hollow cylindrical structures, strung together along the central axis on the core tube. The bottom end of the core tube is located in the middle of the inner ring drill bit. The lower end face of the upper shell is connected to the upper end face of the connecting pipe. The lower shell has an inverted "U"-shaped cross-section, with its upper end face connected to the lower end face of the connecting pipe. The outer ring drill bit is fitted onto the lower end of the inner ring drill bit; the mated inner and outer ring drill bits have a "convex"-shaped cross-section, with the upper part of the inner ring drill bit nested within the upper shell. The outer wall of the core tube has a locking groove that engages with the core tube locking pin, and six retaining rings are distributed circumferentially on the inner wall. One end of the hydraulic rod is located in the corresponding hole of the inner ring drill bit, and the other end contacts the inclined rail on the inner side of the lower shell. A bevel gear is connected to the connecting column of the lower shell via bearing balls, meshing with the outer side of the inner ring drill bit and the inner side of the outer ring drill bit, respectively. Six drill blades are evenly radially distributed on the lower bottom surface of both the outer and inner ring drill bits. The cutting surface of the outer ring drill bit's blades faces clockwise, while the cutting surface of the inner ring drill bit's blades faces counterclockwise. Water holes are provided between the drill blades. There are six circumferentially distributed cutting edges within the inner ring drill bit. Four supporting ribs are circumferentially distributed along the central axis, each divided into three segments, located on the lower shell, connecting pipe, and outer wall of the upper shell, respectively. The source fluid inlet pipe is axially located inside the upper shell, with its bottom end connected to a positioning valve. The drilling fluid inlet pipe is distributed in an "L" shape inside the upper shell, connecting pipe, and lower shell, with one end connected to the positioning valve and the other end connected to a left one-way valve inside the lower shell. The left one-way valve is axially located inside the lower shell, with its upper end connected to the drilling fluid inlet pipe, its lower end connected to the cut-off fluid outlet pipe, and its side end connected to the left guide groove, the other end of which is connected to a left arc-shaped groove. The right one-way valve is axially located inside the lower shell, with its upper end connected to the cut-off fluid inlet pipe, its lower end connected to the drilling fluid outlet pipe, its side end connected to the right guide groove, the other end of which is connected to a right arc-shaped groove. The annular groove is formed by the intersection of the lower shell, the inner annular drill bit, and the outer annular drill bit, connecting the drilling fluid outlet pipe, the cut-off fluid outlet pipe, and the water eye. The core tube locking pin is radially positioned, and the tail end is connected to the drilling fluid inlet pipe through the locking tube.

[0005] In the above scheme, there are four circumferentially arranged connecting posts on the bottom surface of the lower shell. Each connecting post is combined with a bevel gear through a bearing ball. The bevel gear meshes externally with the inner ring drill bit and internally with the outer ring drill bit. Rotation of the inner ring drill bit can drive the outer ring drill bit to rotate in the opposite direction.

[0006] In the above scheme, the tail edge of the cutting edge corresponds to the groove of the inner ring drill bit. The cutting edge can be translated along the direction of the groove. The upper surface of the cutting edge has a limit key corresponding to the limit groove of the inner ring drill bit, which can limit the translation distance of the cutting edge. When the inner ring drill bit starts to rotate counterclockwise, it is pushed into the lower shell by the friction force of the rock core. When the inner ring drill bit starts to rotate clockwise, it is pushed out by the friction force of the rock core.

[0007] In the above scheme, the positioning valve is located inside the upper shell, with the upper end connected to the source fluid inlet pipe and the two sides connected to the drilling fluid inlet pipe and the cut-off fluid inlet pipe. The direction of drilling fluid flow can be controlled by radial movement.

[0008] In the above scheme, the left check valve is located inside the lower shell, with its upper end connected to the drilling fluid inlet pipe, its side end connected to the left guide channel, and its lower end connected to the cut-off fluid outlet pipe. This allows drilling fluid from the drilling fluid inlet pipe to enter the left arc-shaped channel through the left guide channel, and drilling fluid from the left arc-shaped channel to enter the cut-off fluid outlet pipe through the left guide channel. The right check valve, the cut-off fluid inlet pipe, the drilling fluid outlet pipe, the right guide channel, and the right arc-shaped channel are symmetrically arranged on the other side.

[0009] In the above scheme, the inner ring drill bit is nested inside the lower shell. One end of the hydraulic rod is in contact with the inclined rail of the lower shell, and the other end is located in the corresponding hole of the inner ring drill bit. The lower shell has a left arc-shaped groove and a right arc-shaped groove corresponding to the hole of the inner ring drill bit, and the left arc-shaped groove and the right arc-shaped groove are connected to the left guide groove and the right guide groove, respectively.

[0010] Compared with the prior art, the beneficial effects achieved by the present invention are as follows.

[0011] 1. This invention uses a double-drill-bit reverse rotation drilling structure with inner and outer rings, which can effectively reduce the rotation of the drill bit during core sampling, reduce the impact amplitude of the drill bit on the rock core, and improve the integrity rate of the rock core.

[0012] 2. This invention adopts a downhole power design, which can complete more complex coring tasks, while significantly improving drilling efficiency and effectively reducing coring costs.

[0013] 3. This invention uses wireline coring technology, which, compared to core drilling, not only reduces drilling downtime and improves coring efficiency, but also reduces labor and machinery consumption.

[0014] 4. The present invention uses an automatic core-cutting structure, which can automatically cut the rock core when the drill bit reaches the preset length, thereby improving the integrity of the rock core and facilitating wireline coring operations.

[0015] 4. The present invention uses an automatic core-cutting structure, which can automatically cut the rock core when the drill bit reaches the preset length, thereby improving the integrity of the rock core and facilitating wireline coring operations. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 This is a front cross-sectional view of the present invention.

[0018] Figure 3 This is a top cross-sectional view of the upper shell portion of the present invention.

[0019] Figure 4 This is a right-side cross-sectional view of the upper shell portion of the present invention.

[0020] Figure 5 This is a drawing of the cutting blade part of the present invention.

[0021] Figure 6 This is a bottom view of the connection method between the cutting edge and the inner ring drill bit of the present invention.

[0022] Figure 7 This is a schematic diagram of the internal structure of the lower shell of the present invention.

[0023] Figure 8 This is a cross-sectional view of the lower shell portion of the present invention.

[0024] In the diagram: 1. Upper shell, 2. Connecting pipe, 3. Lower shell, 4. Inner ring drill bit, 5. Hydraulic rod, 6. Outer ring drill bit, 7. Core tube, 8. Positioning valve, 9. Upper spring, 10. Core tube retaining pin, 11. Right check valve, 12. Lower spring, 13. Bevel gear, 14. Bearing ball, 15. Cutting edge, 16. Snap ring, 17. Support rib, 18. Drill bit blade, 19. Water eye, 20. Connecting column. 21. Circular groove; 22. Cut-off inlet pipe; 23. Left guide groove; 24. Drill inlet / outlet pipe; 25. Drill inlet / outlet pipe; 26. Right guide groove; 27. Cut-off outlet pipe; 28. Source inlet pipe; 29. ​​Left arc-shaped groove; 30. Right arc-shaped groove; 31. Tail ridge; 32. Sliding groove; 33. Limit key; 34. Limit groove; 35. Positioning pipe; 36. Inclined rail; 37. Positioning annular groove; 38. Left check valve. Detailed Implementation

[0025] In order to improve the integrity and recovery rate of core samples, increase coring efficiency, better adapt to advanced drilling technology, and overcome the shortcomings of existing technologies, the purpose of this invention is to solve some technical problems: to provide a hydraulically driven automatic coring device that has low impact on core samples, high coring efficiency, and wide applicability.

[0026] The technical solution adopted by this invention to solve its technical problem is as follows: This core extractor includes an upper shell, a connecting pipe, a lower shell, an inner ring drill bit, a hydraulic rod, an outer ring drill bit, a core tube, a positioning valve, an upper spring, a core tube locking pin, a right one-way valve, a lower spring, a bevel gear, bearing balls, a cutting edge, a retaining ring, a support ridge, a drill bit blade, a water eye, a connecting column, an annular groove, a cut-off inlet pipe, a left guide groove, a drill inlet / outlet pipe, a drill inlet / outlet pipe, a right guide groove, a cut-off outlet pipe, a source inlet pipe, a left arc-shaped groove, a right arc-shaped groove, a tail ridge, a sliding groove, a limiting key, a limiting groove, a locking pipe, an inclined rail, a locking annular groove, and a left one-way valve. The core tube is a circular tube structure. The upper shell, connecting pipe, lower shell, and inner ring drill bit are all hollow cylindrical structures, strung together along the central axis on the core tube. The bottom end of the core tube is located in the middle of the inner ring drill bit. The lower end face of the upper shell is connected to the upper end face of the connecting pipe. The lower shell has an inverted "U"-shaped cross-section, with its upper end face connected to the lower end face of the connecting pipe. The outer ring drill bit is fitted onto the lower end of the inner ring drill bit; the mated inner and outer ring drill bits have a "convex"-shaped cross-section, with the upper part of the inner ring drill bit nested within the upper shell. The outer wall of the core tube has a locking groove that engages with the core tube locking pin, and six retaining rings are distributed circumferentially on the inner wall. One end of the hydraulic rod is located in the corresponding hole of the inner ring drill bit, and the other end contacts the inclined rail on the inner side of the lower shell. A bevel gear is connected to the connecting column of the lower shell via bearing balls, meshing with the outer side of the inner ring drill bit and the inner side of the outer ring drill bit, respectively. Six drill blades are evenly radially distributed on the lower bottom surface of both the outer and inner ring drill bits. The cutting surface of the outer ring drill bit's blades faces clockwise, while the cutting surface of the inner ring drill bit's blades faces counterclockwise. Water holes are provided between the drill blades. There are six circumferentially distributed cutting edges within the inner ring drill bit. Four supporting ribs are circumferentially distributed along the central axis, each divided into three segments, located on the lower shell, connecting pipe, and outer wall of the upper shell, respectively. The source fluid inlet pipe is axially located inside the upper shell, with its bottom end connected to a positioning valve. The drilling fluid inlet pipe is distributed in an "L" shape inside the upper shell, connecting pipe, and lower shell, with one end connected to the positioning valve and the other end connected to a left one-way valve inside the lower shell. The left one-way valve is axially located inside the lower shell, with its upper end connected to the drilling fluid inlet pipe, its lower end connected to the cut-off fluid outlet pipe, and its side end connected to the left guide groove, the other end of which is connected to a left arc-shaped groove. The right one-way valve is axially located inside the lower shell, with its upper end connected to the cut-off fluid inlet pipe, its lower end connected to the drilling fluid outlet pipe, its side end connected to the right guide groove, the other end of which is connected to a right arc-shaped groove. The annular groove is formed by the intersection of the lower shell, the inner annular drill bit, and the outer annular drill bit, connecting the drilling fluid outlet pipe, the cut-off fluid outlet pipe, and the water eye. The core tube locking pin is radially positioned, and the tail end is connected to the drilling fluid inlet pipe through the locking tube.

[0027] In the above scheme, there are four circumferentially arranged connecting posts on the bottom surface of the lower shell. Each connecting post is combined with a bevel gear through a bearing ball. The bevel gear meshes externally with the inner ring drill bit and internally with the outer ring drill bit. Rotation of the inner ring drill bit can drive the outer ring drill bit to rotate in the opposite direction.

[0028] In the above scheme, the tail edge of the cutting edge corresponds to the groove of the inner ring drill bit. The cutting edge can be translated along the direction of the groove. The upper surface of the cutting edge has a limit key corresponding to the limit groove of the inner ring drill bit, which can limit the translation distance of the cutting edge. When the inner ring drill bit starts to rotate counterclockwise, it is pushed into the lower shell by the friction force of the rock core. When the inner ring drill bit starts to rotate clockwise, it is pushed out by the friction force of the rock core.

[0029] In the above scheme, the positioning valve is located inside the upper shell, with the upper end connected to the source fluid inlet pipe and the two sides connected to the drilling fluid inlet pipe and the cut-off fluid inlet pipe. The direction of drilling fluid flow can be controlled by radial movement.

[0030] In the above scheme, the left check valve is located inside the lower shell, with its upper end connected to the drilling fluid inlet pipe, its side end connected to the left guide channel, and its lower end connected to the cut-off fluid outlet pipe. This allows drilling fluid from the drilling fluid inlet pipe to enter the left arc-shaped channel through the left guide channel, and drilling fluid from the left arc-shaped channel to enter the cut-off fluid outlet pipe through the left guide channel. The right check valve, the cut-off fluid inlet pipe, the drilling fluid outlet pipe, the right guide channel, and the right arc-shaped channel are symmetrically arranged on the other side.

[0031] In the above scheme, the inner ring drill bit is nested inside the lower shell. One end of the hydraulic rod is in contact with the inclined rail of the lower shell, and the other end is located in the corresponding hole of the inner ring drill bit. The lower shell has a left arc-shaped groove and a right arc-shaped groove corresponding to the hole of the inner ring drill bit, and the left arc-shaped groove and the right arc-shaped groove are connected to the left guide groove and the right guide groove, respectively.

Claims

1. A hydraulically driven automatic core extractor, comprising: Upper shell (1), connecting pipe (2), lower shell (3), inner ring drill bit (4), hydraulic rod (5), outer ring drill bit (6), core tube (7), positioning valve (8), upper spring (9), core tube locking pin (10), right check valve (11), lower spring (12), bevel gear (13), bearing ball (14), cutting edge (15), snap ring (16), support ridge (17), drill bit blade (18), water eye (19), connecting column (20), annular groove (21), cut-off inlet pipe (22), left guide groove (23), drilling inlet / outlet pipe (24), drilling inlet / outlet pipe (25), right guide groove (26), cut-off outlet pipe (27), source inlet pipe (28), left arc groove (29), right arc groove (30), tail The components are: ridge (31), slide (32), limit key (33), limit groove (34), locking tube (35), inclined rail (36), locking ring groove (37), and left one-way valve (38). The core tube (7) is a circular tube structure. The upper shell (1), connecting tube (2), lower shell (3), and inner ring drill bit (4) are all hollow cylindrical structures, strung together along the central axis on the core tube (7). The bottom end of the core tube (7) is located in the middle of the inner ring drill bit (4). The lower end face of the upper shell (1) is connected to the upper end face of the connecting tube (2). The lower shell (3) has an inverted "U" shaped cross-section, with its upper end face connected to the lower end face of the connecting tube (2). The outer ring drill bit (6) is fitted onto the lower end of the inner ring drill bit (4), and the well-fitted inner ring drill bit (4) and outer ring drill bit (6) are... The cross-section of the ring drill bit (6) is convex. The upper section of the inner ring drill bit (4) is nested with the upper shell (1). The outer wall of the core tube (7) has a locking ring groove (37) that cooperates with the core tube locking pin (10). Six retaining rings (16) are distributed circumferentially on the inner wall. One end of the hydraulic rod (5) is located in the corresponding hole of the inner ring drill bit (4), and the other end is in contact with the inclined rail (36) on the inner side of the lower shell (3). The bevel gear (13) is connected to the connecting column (20) of the lower shell (3) through the bearing ball (14), and meshes with the outer side of the inner ring drill bit (4) and the inner side of the outer ring drill bit (6) respectively. Six drill blades (18) are evenly radially distributed on the bottom surface of the outer ring drill bit (6) and the inner ring drill bit (4). The drill blades (18) of the outer ring drill bit (6) The cutting surface of the inner ring drill bit (4) is oriented clockwise, and the cutting surface of the drill bit blade (18) is oriented counterclockwise. Water holes (19) are provided between the drill bit blades (18). There are 6 cutting edges (15) in total, which are circumferentially distributed in the inner ring drill bit (4). There are 4 supporting edges (17) circumferentially distributed along the central axis. Each edge is divided into 3 segments, which are located on the outer wall of the lower shell (3), the connecting pipe (2), and the upper shell (1), respectively. The source liquid inlet pipe (28) is axially located in the upper shell (1) and the bottom end is connected to the positioning valve (8). The drilling liquid inlet pipe (25) is distributed in an "L" shape in the upper shell (1), the connecting pipe (2), and the lower shell (3). One end is connected to the positioning valve (8) and the other end is connected to the left check valve (38) in the lower shell (3).The left one-way valve (38) is axially located inside the lower shell (3), with its upper end connected to the drilling inlet pipe (25), its lower end connected to the cut-off outlet pipe (27), and its side end connected to the left guide groove (23). The other end of the left guide groove (23) is connected to the left arc groove (29). The right one-way valve (11) is axially located inside the lower shell (3), with its upper end connected to the cut-off inlet pipe (22), its lower end connected to the drilling outlet pipe (24), and its side end connected to the right guide groove (26). The other end of the right guide groove (26) is connected to the right arc groove (30). The annular groove (21) is formed by the intersection of the lower shell (3), the inner annular drill bit (4), and the outer annular drill bit (6), connecting the drilling outlet pipe (24), the cut-off outlet pipe (27), and the water eye (19). The core tube locking pin (10) is radially arranged, and its tail end is connected to the drilling inlet pipe (25) through the locking tube (35).

2. The hydraulically driven automatic core extractor according to claim 1, characterized in that: The lower shell (3) has four circumferentially arranged connecting posts (20) on its bottom surface. Each connecting post (20) is combined with a bevel gear (13) through a bearing ball (14). The bevel gear (13) meshes externally with the inner ring drill bit (4) and internally with the outer ring drill bit (6). The rotation of the inner ring drill bit (4) can drive the outer ring drill bit (6) to rotate in the opposite direction.

3. The hydraulically driven automatic core extractor according to claim 1, characterized in that: The tail edge (31) of the cutting edge (15) corresponds to the groove (32) of the inner ring drill bit (4), and the cutting edge (15) can be translated along the direction of the groove (32).

4. The hydraulically driven automatic core extractor according to claim 1, characterized in that: The positioning valve (8) is located inside the upper shell (1), with the upper end connected to the source liquid inlet pipe (28) and the two sides connected to the drilling liquid inlet pipe (25) and the cut-off liquid inlet pipe (22).

5. A hydraulically driven automatic core extractor according to claim 1, characterized in that: The left one-way valve (38) is located inside the lower shell (3), with the upper end connected to the drilling fluid inlet pipe (25), the side end connected to the left guide groove (23), and the lower end connected to the cut-off fluid outlet pipe (27), so that the drilling fluid from the drilling fluid inlet pipe (25) enters the left arc groove (29) through the left guide groove (23), and the drilling fluid from the left arc groove (29) enters the cut-off fluid outlet pipe (27) through the left guide groove (23). The right one-way valve (11), the cut-off fluid inlet pipe (22), the drilling fluid outlet pipe (24), the right guide groove (26), and the right arc groove (30) are symmetrically arranged on the other side.

6. A hydraulically driven automatic core extractor according to claim 1, characterized in that: The inner ring drill bit (4) is nested inside the lower shell (3). One end of the hydraulic rod (5) is in contact with the inclined rail (36) of the lower shell (3), and the other end is located in the corresponding hole of the inner ring drill bit (4). The lower shell (3) has a left arc groove (29) and a right arc groove (30) corresponding to the hole of the inner ring drill bit (4). The left arc groove (29) and the right arc groove (30) are respectively connected to the left guide groove (23) and the right guide groove (26).

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