A coring tool for loose formations

Abstract

This invention relates to the field of coring technology and discloses a coring tool for loose formations, including an outer tube assembly and a spring-loaded retrieval nozzle, a positioning frame with equidistantly distributed ball bearings rotatably connected to the top of the positioning frame, an inner core tube, a connecting mechanism located at the end of the spring-loaded retrieval nozzle and used to connect the inner core tube, an inner concave cone with a minimum inner diameter consistent with the inner diameter of the inner core tube, and a rotary cutting mechanism located inside the inner concave cone. When the spring-loaded retrieval nozzle is lifted during coring, the rotary cutting mechanism can cut the core column through the connecting mechanism. This invention utilizes the rising of the spring-loaded retrieval nozzle to cause multiple rotary cutting blades to rotate and close. The rotation and closure of the multiple rotary cutting blades, which are pressed together end to end, not only cuts the core column but also forms an interlocking and overlapping base structure, ensuring that the core column remains intact during the cutting process and preventing the core column from falling off due to gravity during extraction, thereby improving the coring rate of loose formations.

Description

Technical Field

[0001] This invention relates to the field of coring technology, and more specifically, to a coring tool for loose formations. Background Technology

[0002] During coal mining, mine water hazards occur frequently. Water inrushes from the "quaternary aquifers" (water-bearing layers at the bottom of Quaternary loose sediments) have repeatedly caused property damage to mines, with roof water inrushes being a major source of underground water hazards. Therefore, it is necessary to evaluate the hydrogeological conditions of these aquifers. The most direct means of determining the basic geology of these aquifers is geological exploration, which involves strategically placing observation wells and using core drilling tools to collect core samples from the aquifers to analyze lithological structure (such as grain composition and degree of cementation).

[0003] Existing coring tools mainly consist of two parts: an outer tube assembly and an inner tube assembly. The outer tube assembly mainly includes an outer drill pipe, a reamer, a drill bit, and a spring clip. The inner tube assembly mainly includes an inner core tube, a snap ring head, and a snap ring retrieval spearhead. By installing the inner tube assembly inside the outer tube assembly, the drill pipe drives the outer tube assembly to drill into the rock formation. The inner core tube can be kept in a non-rotating state by the installed snap ring head and snap ring retrieval spearhead. In this way, the rock core can enter the downward-moving inner core tube. Then, the retrieval tool hooks the snap ring retrieval spearhead and pulls the inner tube assembly upward, thereby retrieving the rock core column from the inner core tube.

[0004] The key to successful coring with the aforementioned coring drill bit lies in the ability of the spring clip to clamp the core column and pull it upwards along with the inner core tube to break it off. However, the "quadruple aquifer (the bottom of the loose sediments of the Quaternary)" strata are loose and the core strength is low. When the spring clip clamps the core column, it is easy for the core column to be crushed under pressure, or when the spring clip pulls the core column upwards to break it off, the core column collapses directly, thus failing to form a complete core column, resulting in a low coring rate. Summary of the Invention

[0005] This invention provides a coring drill for loose formations, solving the technical problem in related technologies where loose formations with low rock core strength result in low coring rates.

[0006] The present invention provides a coring tool for loose formations, including an outer tube assembly and a spring-loaded retrieval head disposed therein, and a positioning frame fixedly connected inside the outer tube assembly, wherein the top of the positioning frame is rotatably connected with equally spaced balls.

[0007] The inner core tube is disposed inside the outer tube assembly;

[0008] A connecting mechanism is provided at the end of the spring-loaded spearhead and is used to connect the inner core tube;

[0009] An inward-retracting cone is threadedly connected to the end of the inner core tube and away from the connecting mechanism via a threaded connector A. The minimum inner diameter of the inward-retracting cone is the same as the inner diameter of the inner core tube.

[0010] The rotary cutting mechanism is located inside the inner cone. When the core is extracted and the spring-loaded retrieval spearhead is lifted, the rotary cutting mechanism can cut the core column through the connecting mechanism.

[0011] Preferably, the inner core tube is composed of two half-tubes. One half-tube has a perpendicular through block and splicing block fixed on its outer side, and the other half-tube has a perpendicular through groove and splicing groove on its outer side. The splicing block is adapted to the splicing groove.

[0012] Preferably, the connecting mechanism includes two threaded joints B that are threadedly connected to the end of the spring-loaded spearhead and the inner core tube, respectively. A connecting rod and a hollow column are fixedly connected to the two threaded joints B at their close ends. The connecting rod passes through the hollow column and is fixedly connected to a connecting sleeve. Two connecting pins are fixedly connected inside the connecting sleeve. A connecting column extending into the connecting sleeve is rotatably connected inside the hollow column. Two spiral grooves are formed on the outside of the connecting column. The two connecting pins are movably connected inside the two spiral grooves, respectively.

[0013] Preferably, the hollow column has two rotating grooves A on its exterior, and a connecting member A is provided inside both rotating grooves A.

[0014] Preferably, the hollow column has circumferentially distributed drainage holes on its exterior, and the circumferentially distributed drainage holes are radially arranged.

[0015] Preferably, the connector A includes two connecting brackets fixedly connected to the outside of the connecting column. The two connecting brackets pass through two rotating slots A and extend axially. The outside of the two connecting brackets is fixedly connected to a positioning ring that contacts the ball.

[0016] Preferably, the rotary cutting mechanism includes a hollow ring embedded between the threaded joint A and the inner tapered cone. The inner side of the hollow ring has equidistantly distributed limiting holes. A pin A is rotatably connected inside the limiting holes. A crescent-shaped rotary cutting blade is fixedly connected to the end of the pin A away from the limiting holes. A pin B is fixedly connected to the side of the rotary cutting blade away from the pin A. The pins A and B are far apart from each other. The ends of the plurality of rotary cutting blades are pressed together in sequence. A connecting piece B is provided inside the hollow ring.

[0017] Preferably, the connector B includes a sealing ring rotatably connected inside the hollow ring, and two rotating grooves B formed outside the hollow ring. Radial grooves are equidistantly formed on the outer side of the sealing ring. The pin B is slidably connected inside the corresponding radial groove. Both rotating grooves B extend to the outer side of the threaded joint A. A connecting plate fixedly connected to the sealing ring is rotatably connected inside both rotating grooves B.

[0018] Preferably, the two connecting plates are fixedly connected to the two connecting brackets respectively by mounting screws.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. In the process of core drilling, the outer diameter of the core column entering the inner core tube can be reduced to approximately the inner diameter of the inner core tube by the inward contraction cone. The inward contraction can compress the core column, making its structure more compact, and can peel off the outer layer of the core column in contact with the flushing fluid, so as to retain the more representative core part inside. That is, after the core column is compacted by the inward contraction cone and the outer layer is peeled off, its resistance to breakage and deformation is improved.

[0021] 2. This invention employs a combination of a connecting mechanism and a rotary cutting mechanism. By using the lifting spring-loaded retrieval head of the retrieval device, the connecting sleeve moves upward and drives the connecting column to rotate through the connecting pin and spiral groove. This causes the sealing ring to rotate, which in turn drives the rotary cutting blades to rotate and close. The rotation and closure of multiple rotary cutting blades pressed together end to end not only cuts the core column but also forms an interlocking base structure. The rising of the spring-loaded retrieval head causes multiple rotary cutting blades to rotate and close, ensuring that the core column remains intact during the cutting process and preventing the core column from falling off due to gravity during extraction, thereby improving the core recovery rate of loose strata.

[0022] 3. This invention separates the two half-tubes by pushing them in a direction away from each other, causing the splicing block to detach from the splicing groove. The inner core tube is composed of two interlocking half-tubes, so as to remove the rock core column in the inner core tube and avoid the rock core column from being broken or the structure damaged by heavy hammering. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 for Figure 1 Enlarged view of the structure at point A in the image;

[0025] Figure 3 This is a schematic diagram of the positioning frame and ball bearings in this invention;

[0026] Figure 4 This is a partial structural schematic diagram of the present invention;

[0027] Figure 5 for Figure 4 Enlarged view of the structure at point B in the image;

[0028] Figure 6 for Figure 5 Enlarged view of the structure at point C in the image;

[0029] Figure 7 for Figure 4 A schematic diagram of the split structure;

[0030] Figure 8 This is a schematic diagram of the connecting mechanism in this invention;

[0031] Figure 9 This is a schematic diagram of the connecting pin in this invention;

[0032] Figure 10 This is a schematic diagram of the first structure of the rotary cutting mechanism in this invention;

[0033] Figure 11 This is a schematic diagram of the second structure of the rotary cutting mechanism in this invention;

[0034] Figure 12 This is a schematic diagram of the third structure of the rotary cutting mechanism in this invention;

[0035] Figure 13 This is a schematic diagram of the rotary cutting blade in this invention.

[0036] In the diagram: 10. Outer tube assembly; 20. Spring-loaded spearhead; 30. Positioning frame; 31. Ball bearing; 40. Inner core tube; 41. Splicing block; 42. Splicing groove; 50. Connecting mechanism; 51. Connecting rod; 52. Hollow column; 53. Connecting sleeve; 54. Connecting pin; 55. Connecting column; 56. Spiral groove; 57. Connecting frame; 58. Positioning ring; 60. Inner tapered cone; 70. Rotary cutting mechanism; 71. Hollow ring; 72. Pin A; 73. Rotary cutting blade; 74. Pin B; 75. Sealing ring; 76. Radial groove; 77. Connecting plate. Detailed Implementation

[0037] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, some features described in the examples may be combined in other examples.

[0038] like Figure 1 - Figure 5 and Figure 7As shown, this embodiment provides a coring tool for loose formations, including an outer tube assembly 10 and a spring-loaded retrieval spearhead 20 disposed therein. The spring-loaded retrieval spearhead 20 enters and exits the interior of the outer tube assembly 10 via a retrieval device. The upper part of the spring-loaded retrieval spearhead 20 rotates with the outer tube assembly 10. The outer tube assembly 10, the spring-loaded retrieval spearhead 20, and the retrieval device are all prior art. Therefore, the specific structure of the outer tube assembly 10, the spring-loaded retrieval spearhead 20, and the retrieval device is not described in detail in this embodiment. It also includes:

[0039] The positioning frame 30 is fixedly connected inside the outer tube assembly 10. The top of the positioning frame 30 is rotatably connected with equally spaced balls 31. The balls 31 on the positioning frame 30 are used to limit the height of the positioning ring 58 in the following connection mechanism 50.

[0040] The inner core tube 40 is located inside the outer tube assembly 10. The inner core tube 40 is composed of two half tubes. One half tube has a perpendicular through block and splicing block 41 fixed on its outer side. The other half tube has a perpendicular through groove and splicing groove 42 on its outer side. The splicing block 41 is adapted to the splicing groove 42. By pushing the two half tubes in a direction away from each other, the splicing block 41 is disengaged from the splicing groove 42, and the two half tubes can be separated. The inner core tube 40 is composed of two interlocking half tubes to remove the rock core column in the inner core tube 40, avoiding the rock core column from being broken or the structure from being hit by a heavy hammer.

[0041] A connecting mechanism 50 is provided at the end of the spring-loaded spearhead 20 and is used to connect the inner core tube 40;

[0042] The inner concave cone 60 is threadedly connected to the end of the inner core tube 40 and away from the connecting mechanism 40 via threaded connector A. The minimum inner diameter of the inner concave cone 60 is the same as the inner diameter of the inner core tube 40. The outer diameter of the core column entering the inner core tube 40 can be reduced to approximately the inner diameter of the inner core tube 40 by the inner concave cone 60. During the drilling and coring process, the inner concave action can compress the core column, making its structure more compact. It can also peel off the outer layer of the core column that is in contact with the flushing fluid (the outer layer of the core column will come into contact with the flushing fluid, which may affect the structure and composition of the core column), so as to retain a more representative core part inside. That is, through the inner concave compaction and outer layer peeling of the inner concave cone 60, the structure of the core column is made more compact, which improves its resistance to breakage and deformation.

[0043] The rotary cutting mechanism 70 is located inside the inner retracting cone 60. When the core is being retrieved by lifting the spring clip 20, the rotary cutting mechanism 70 can cut the core column through the connecting mechanism 50.

[0044] Among them, such as Figure 8 - Figure 9As shown, the connecting mechanism 50 includes two threaded joints B that are threadedly connected to the ends of the spring-loaded spearhead 20 and the inner core tube 40, respectively. The ends of the two threaded joints B that are close to each other are respectively fixedly connected to a connecting rod 51 and a hollow column 52. In the initial state, the top of the hollow column 52 abuts against the bottom of the upper threaded joint B. The connecting rod 51 passes through the hollow column 52 and is fixedly connected to a connecting sleeve 53. Two connecting pins 54 are fixedly connected inside the connecting sleeve 53. A connecting column 55 extending into the connecting sleeve 53 is rotatably connected inside the hollow column 52. In the initial state, the top of the connecting column 55 is connected to the inner top of the connecting sleeve 53. Two spiral grooves 56 are opened on the outside of the connecting column 55. The two connecting pins 54 are movably connected inside the two spiral grooves 56. When the spring-loaded spearhead 20 is lifted by the retrieval device, the connecting rod 51 will drive the two connecting pins 54 to move upward through the connecting sleeve 53. The two connecting pins 54 slide inside the two spiral grooves 56, thereby driving the connecting column 55 to rotate.

[0045] Two rotating grooves A are opened on the outside of the hollow column 52. A connecting piece A is provided inside the two rotating grooves A. The hollow column 51 has circumferentially distributed water leakage holes on its outside. The circumferentially distributed water leakage holes are radial. After the flushing liquid enters the hollow column 51 through the two rotating grooves A, it can leak out through the circumferentially distributed water leakage holes, which are inclined downward.

[0046] The connector A includes two connecting brackets 57 fixedly connected to the outside of the connecting post 55. The two connecting brackets 57 pass through two rotating slots A and extend axially. The two connecting brackets 57 are fixedly connected to a positioning ring 58 that contacts the ball 31. When the connecting post 55 rotates, it can drive the two connecting brackets 57 and the positioning ring 58 to rotate synchronously.

[0047] Among them, such as Figure 6 and Figure 10 - Figure 13 As shown, the rotary cutting mechanism 70 includes a hollow ring 71 embedded between the threaded joint A and the inner tapered cone 60. The inner diameter of the hollow ring 71 is the same as the inner diameter of the inner core tube 40. The inner side of the hollow ring 71 is provided with equidistantly distributed limiting holes. A pin A72 is rotatably connected inside the limiting holes. A crescent-shaped rotary cutting blade 73 is fixedly connected to the end of the pin A72 away from the limiting holes. The rotary cutting blade 73 can rotate around the axis of the pin A72. A pin B74 is fixedly connected to the side of the rotary cutting blade 73 away from the pin A72. The pin A72 and the pin B74 are far apart from each other. The heads and tails of the multiple rotary cutting blades 73 are pressed together in sequence. When the multiple rotary cutting blades 73 that are pressed together in sequence rotate and close, they can not only cut the rock core column, but also form an interlocking bottom support structure, which plays the role of bottom support support for the rock core column and prevents the rock core column from falling off during the lifting process.

[0048] The connector B includes a sealing ring 75 rotatably connected inside the hollow ring 71, and two rotating grooves B opened outside the hollow ring 71. Radial grooves 76 are equidistantly opened on the outer side of the sealing ring 75. The pin B74 is slidably connected inside the corresponding radial groove 76. By rotating the sealing ring 75, the pin B74 can be driven to move through the radial grooves 76, so that the rotary cutting blades 73 can rotate around the axis of the pin A72 to close. Both rotating grooves B extend to the outer side of the threaded joint A. Both rotating grooves B are rotatably connected to the connecting plate 77 fixedly connected to the sealing ring 75. The two connecting plates 77 are fixedly connected to the two connecting frames 57 respectively by mounting screws. That is, when the spring clip spearhead 20 is pulled out and the connecting column 55 is rotated, the sealing ring 75 can be driven to rotate through the two connecting frames 57 and the two connecting plates 77, so that multiple rotary cutting blades 73 can rotate and close to cut the core column and support the bottom.

[0049] Through the above structure, the rising of the spring-loaded spearhead 20 causes multiple rotary cutting blades 73 to rotate and close. The multiple rotary cutting blades 73, which are pressed together from end to end, can not only cut the core column, but also form an interlocking bottom support structure to ensure that the core column remains intact during the cutting process and prevent the core column from falling off due to gravity during the extraction process.

[0050] The specific working principle of this implementation is as follows: Figure 1 As shown, after the assembly of each component is completed, the drill rod drives the outer tube assembly 10 to drill downwards and causes the inner core tube 40 to be cored downwards. During the drilling process, the flushing fluid moves downwards between the outer tube assembly 10 and the inner core tube 40 to cool the drill bit and remove slag. During the cored process, the outer diameter of the core column entering the inner core tube 40 can be reduced to approximately the inner diameter of the inner core tube 40 by the inner constriction cone 60, so as to compact the core column and peel off the outer layer, thereby improving the structural strength of the core column entering the inner core tube 40.

[0051] After completing the preset core sampling length (the single core sampling length for loose strata should not be too long), remove the drill rod and lift the spring-loaded retrieval spearhead 20 upwards using the retrieval tool. This causes the connecting rod 51 to drive the two connecting pins 54 upwards through the connecting sleeve 53, allowing the two connecting pins 54 to slide inside the two spiral grooves 56 respectively. This causes the connecting column 55 to rotate, and the rotating connecting column 55 drives the two connecting plates 77 to rotate through the two connecting frames 57. This causes the sealing ring 75 to rotate and drive the pin shaft B74 to move through the radial sliding groove 76, so that the rotary cutting blade 73 can rotate around the axis of the pin shaft A72 to close. This causes multiple rotary cutting blades 73 to rotate and close. When the multiple rotary cutting blades 73, which are pressed together from end to end, rotate and close, they can not only cut the rock core column, but also form an interlocking and overlapping bottom support structure.

[0052] After the multiple rotary cutting blades 73 are fully closed, the top of the connecting sleeve 53 contacts the inner top of the hollow column 52. That is, the spring-loaded spearhead 20, which continues to rise, can drive the inner core tube 40 to rise through the contacting connecting sleeve 53 and the hollow column 52. During the process of the inner core tube 40 driving the cut rock core column inside it to rise, the multiple rotary cutting blades 73 that are rotated and closed provide bottom support for the bottom of the rock core column.

[0053] After the inner core tube 40 is removed from the outer tube assembly 10, rotate to remove the spring clip spearhead 20 and remove the mounting screws between the connecting plate 77 and the connecting frame 57 to disconnect the connection between the connecting mechanism 50 and the rotary cutting mechanism 70. Then, rotate to remove the inner retraction cone 60 and the connecting mechanism 50 in sequence, so that the inner core tube 40 is independent. At this time, by pushing the two halves of the inner core tube 40 in a direction away from each other, the splicing block 41 is separated from the splicing groove 42, and the two halves can be separated to remove the rock core column.

[0054] After removing the core column, reassemble the various components in sequence and continue drilling and coring.

[0055] The embodiments of the present invention have been described above, but the embodiments are not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the embodiments described above, all of which are within the protection scope of the embodiments described above.

Claims

1. A coring tool for loose formations, comprising an outer tube assembly (10) and a spring-loaded retrieval head (20) disposed therein, characterized in that, Also includes: The positioning frame (30) is fixedly connected inside the outer tube assembly (10), and the top of the positioning frame (30) is rotatably connected with equally spaced balls (31). The inner core tube (40) is disposed inside the outer tube assembly (10); A connecting mechanism (50) is provided at the end of the spring-loaded spearhead (20) and is used to connect the inner core tube (40). The inner tapered cone (60) is threaded to the end of the inner core tube (40) and away from the connecting mechanism (40) via a threaded connector A. The minimum inner diameter of the inner tapered cone (60) is the same as the inner diameter of the inner core tube (40). The rotary cutting mechanism (70) is located inside the inner cone (60). When the core is taken and the spring-loaded spearhead (20) is lifted, the rotary cutting mechanism (70) can cut the core column through the connecting mechanism (50).

2. A coring tool for loose formations according to claim 1, characterized in that, The inner core tube (40) is composed of two half tubes. A perpendicular through block and splicing block (41) are fixed on the outside of one half tube, and a perpendicular through groove and splicing groove (42) are opened on the outside of the other half tube. The splicing block (41) and the splicing groove (42) are adapted to each other.

3. A coring tool for loose formations according to claim 2, characterized in that, The connecting mechanism (50) includes two threaded joints B that are threaded to the ends of the spring-loaded spearhead (20) and the inner core tube (40), respectively. The ends of the two threaded joints B that are close to each other are respectively fixedly connected to a connecting rod (51) and a hollow column (52). The connecting rod (51) passes through the hollow column (52) and is fixedly connected to a connecting sleeve (53). The connecting sleeve (53) is fixedly connected to two connecting pins (54). The hollow column (52) is rotatably connected to a connecting column (55) that extends into the connecting sleeve (53). The connecting column (55) has two spiral grooves (56) on its outside. The two connecting pins (54) are movably connected to the inside of the two spiral grooves (56).

4. A coring tool for loose formations according to claim 3, characterized in that, The hollow column (52) has two rotating grooves A on its outside, and the two rotating grooves A are connected to each other.

5. A coring tool for loose formations according to claim 4, characterized in that, The hollow column (51) has circumferentially distributed drainage holes on its exterior, and the circumferentially distributed drainage holes are radial.

6. A coring tool for loose formations according to claim 5, characterized in that, The connector A includes two connecting brackets (57) fixedly connected to the outside of the connecting column (55). The two connecting brackets (57) pass through two rotating slots A and extend axially. The two connecting brackets (57) are fixedly connected to a positioning ring (58) that contacts the ball (31).

7. A coring tool for loose formations according to claim 6, characterized in that, The rotary cutting mechanism (70) includes a hollow ring (71) embedded between the threaded joint A and the inner tapered cone (60). The hollow ring (71) has equidistantly distributed limiting holes on its inner side. A pin A (72) is rotatably connected inside the limiting holes. A crescent-shaped rotary cutting blade (73) is fixedly connected to one end of the pin A (72) away from the limiting holes. A pin B (74) is fixedly connected to one side of the rotary cutting blade (73) away from the pin A (72). The pin A (72) and the pin B (74) are far apart from each other. The heads and tails of the multiple rotary cutting blades (73) are pressed together in sequence. A connector B is provided inside the hollow ring (71).

8. A coring tool for loose formations according to claim 7, characterized in that, The connector B includes a sealing ring (75) rotatably connected inside the hollow ring (71), and two rotating grooves B opened outside the hollow ring (71). Radial grooves (76) are equidistantly opened on the outer side of the sealing ring (75). The pin B (74) is slidably connected inside the corresponding radial groove (76). Both rotating grooves B extend to the outer side of the threaded joint A. Both rotating grooves B are rotatably connected to a connecting plate (77) fixedly connected to the sealing ring (75).

9. A coring tool for loose formations according to claim 8, characterized in that, The two connecting plates (77) are fixedly connected to the two connecting brackets (57) respectively by mounting screws.

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