A dual-structure claw coring tool with tooth-engraved differential and adjustable gap

Abstract

The present invention discloses a dual-claw coring tool with a tooth-embedded differential and adjustable gap, comprising a differential assembly, a locking and suspension assembly, an outer cylinder assembly, an inner cylinder assembly, a shieldable dual-core claw structure assembly, and a coring drill bit. During coring drilling, the clamp-type core claw is located between the shielding sleeve and the necking sleeve and does not directly contact the core. When core cutting is required, both downward pressing and upward pulling core cutting methods are used simultaneously. The differential assembly and the locking and suspension assembly first press down to cut the shear pin, the petal-type retractable core claw retracts, and the shielding sleeve is lifted to expose the clamp-type core claw. The differential assembly drives the inner sleeve and the outer sleeve to move upward at the same time. After the locking block touches the lower positioning joint, the inner sleeve continues to be lifted, and the shielding sleeve is pulled out of the clamp-type core claw, completing the upward pulling and core cutting process.

Description

Technical Field

[0001] The invention relates to the field of downhole drilling tools for oil and natural gas exploration and development, in particular to a double-structured claw coring tool with tooth-engaged differential and adjustable clearance. Background Art

[0002] As terrestrial oil and gas resources gradually decrease, deepwater oil development is becoming an option.

[0003] Currently, oil development in the South China Sea is gradually entering the deepwater area, but the domestic deepwater coring tools and technologies that match it are still blank.

[0004] At present, the commonly used drilling coring tools in China include pull-up coring tools suitable for hard formations and mechanical and hydraulic pressure coring tools suitable for loose formations. There is a lack of a universal coring tool suitable for soft to hard formations.

[0005] Characteristics of deepwater coring operations:

[0006] 1) When the floating drilling platform is in a floating state, the hull moves up and down with the swell, and the coring drill bit is easily separated from the bottom of the well, resulting in repeated core cutting and the core not forming a column;

[0007] 2) In deepwater exploration areas, there is a lack of existing drilling data, the stratum lithology is unclear, and the selection of coring tools is difficult. Unsuitable coring tools greatly increase the probability of coring.

[0008] 3) The daily drilling cost is high, and continuous coring of multiple wells is required, so the coring tools need to be highly reliable.

[0009] Generally speaking, China lacks a special coring tool and related process technology that is compatible with deep-water floating platforms. Summary of the Invention

[0010] The purpose of the present invention is to address the problems existing in the current deepwater coring operation technology and provide a double-claw coring tool with a tooth-engaged differential adjustable gap suitable for deepwater coring. At the same time, the present invention also provides a coring method using the tool.

[0011] The technical solution of the present invention includes:

[0012] A dual-structure claw coring tool with a tooth-engaged differential and adjustable gap comprises a differential assembly (100), a ball seat supporting a steel ball (200), a locking and hanging assembly (300), an outer cylinder assembly (400), an inner cylinder assembly (500), a shieldable dual-core claw structure assembly (600), and a coring drill bit (700); the differential assembly (100), the locking and hanging assembly (300), the outer cylinder assembly (400), the shieldable dual-core claw structure assembly (600), and the coring drill bit (700) are connected in sequence from top to bottom, and the upper part of the inner cylinder assembly (400) is connected to the locking and hanging assembly (300).

[0013] Furthermore, the shieldable double core claw structure assembly (600) includes an inner sliding sleeve (35), a lower positioning joint (37), an outer sliding sleeve (36), a lower locking block (38), a shielding sleeve (40), a necking sleeve short section (39), a clamp-type core claw (41), a necking sleeve (42), and a flap-type retractable core claw (43);

[0014] The lower portion of the inner cylinder assembly (400) is connected to the inner sliding sleeve (35) and the shielding sleeve (40) in sequence;

[0015] The outer sliding sleeve (36) is connected to the neck sleeve short section (39), the neck sleeve (42), and the flap-type retractable core claw (43) in sequence;

[0016] The outer sliding sleeve (36) and the inner sliding sleeve (35) are connected and fixed by shear pins.

[0017] Furthermore, the differential assembly (100) includes a toothed upper joint (1), a 50 ball seat (3), a toothed inner positioning joint (4), a shear fixing screw (5), a toothed lower joint (6), a gap adjustment inner joint (7), a gap adjustment outer joint (8), an adjustable gap inner rod (10), and a toothed locking block (44);

[0018] The upper portion of the toothed upper joint (1) is connected to the upper drilling tool via a threaded buckle, and the lower portion of the toothed upper joint (1) is connected to the gap adjustment external joint (8) via a threaded buckle;

[0019] The gap adjustment outer joint (8) is connected to the gap adjustment inner joint (7) via a threaded buckle;

[0020] The tooth-embedded inner positioning joint (4) is connected to the tooth-embedded upper joint (1) via a shear fixing screw (5);

[0021] The gap adjustment inner joint (7) is connected to the gap adjustable inner rod (10) via a threaded buckle.

[0022] Furthermore, the tooth-embedded upper joint (1) and the tooth-embedded lower joint (6) cooperate with each other through a spline, and a tooth-embedded locking block (44) is provided between the tooth-embedded upper joint (1) and the tooth-embedded lower joint (6), and the tooth-embedded locking block (44) axially limits the tooth-embedded upper joint (1) and the tooth-embedded lower joint (6).

[0023] Furthermore, when the gap adjustment inner joint (7) rotates, the gap-adjustable inner rod (10) and the outer cylinder (32) maintain a constant relative position, and the gap adjustment inner joint (7) can move axially relative to the outer cylinder.

[0024] Furthermore, the locking and suspension assembly (300) includes 40 ball seats (11), a pressure rod (14), a telescopic head (13), a positioning joint (15), a locking block (16), an inner positioning joint (17), a pressure seat (18), an upper shear ring (20), an upper shear screw (19), a lower shear ring (22), a lower shear screw (21), a bearing box (23), a suspension shaft (24), a bearing ring (25), 19 steel balls (26), a bearing support (27), a water diversion joint (28), and 30 ball seats (31);

[0025] The positioning joint (15) is connected to the gap adjustment inner joint (7) through a threaded buckle, the positioning joint (15) is connected to the inner positioning joint (17) through a locking block (16), the telescopic head (13) is connected to the inner positioning joint (17) through a threaded buckle, the inner positioning joint (17) is connected to the pressure seat (18) through a threaded buckle, the pressure seat (18) is connected to the bearing box (23), the bearing box (23) is connected to the bearing support (27) through a threaded buckle, the suspension shaft (24) is connected to the water diversion joint (28) through a threaded buckle, and the water diversion joint (28) is connected to the ball seat 30 (31) through a threaded buckle;

[0026] The bearing box (23), bearing ring (25), bearing support (27), 19 steel balls (26), and suspension shaft (24) are combined together through their own geometric shapes, and are pressed together by gravity when the tool is used;

[0027] The upper shear ring (20) is connected to the pressure seat (18) via an upper shear screw (19), and the lower shear ring (22) is connected to the pressure seat (18) via a lower shear screw (21).

[0028] Furthermore, the ball seat supporting steel balls (200) include 30 steel balls (30), 40 steel balls (11), and 50 steel balls (2).

[0029] Furthermore, the diameters of the steel balls are all equal to the diameters of the corresponding ball seats, and the diameters of the 30 steel balls (30), 40 steel balls (11), and 50 steel balls (2) increase in sequence.

[0030] Furthermore, the outer cylinder assembly (400) includes an upper joint (9), an upper centralizer (29), an outer cylinder (32), and a lower centralizer (34) which are sequentially connected from top to bottom.

[0031] Furthermore, the outer sliding sleeve (36) is provided with two evenly distributed key slots for cooperating with the lower locking block (38);

[0032] The inner surface of the lower locking block (38) cooperates with the shielding sleeve (40), and the outer surface cooperates with the lower positioning joint (37), and the outer diameter of the lower locking block (38) is larger than the inner diameter of the lower positioning joint (37).

[0033] The advantages of the present invention are:

[0034] The structure avoids repeated core cutting caused by deepwater operations and prevents the core from being unable to form a column; when the lithology of the formation is unknown, it provides a universal coring tool suitable for soft to hard formations; when multiple barrels are continuously coring in deepwater operations, the tool has a high reliability effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the overall structure of the dual-structured claw coring tool with differentially adjustable gaps and teeth according to the present invention.

[0036] Figure 2 This is a schematic diagram of the upper structure of the dual-structured claw coring tool with differentially adjustable gap and teeth according to the present invention.

[0037] Figure 3 This is a schematic diagram of the middle structure of the dual-structured claw coring tool with differentially adjustable gap and teeth according to the present invention.

[0038] Figure 4 This is a schematic diagram of the lower structure of the dual-structured claw coring tool with differentially adjustable gap and teeth according to the present invention.

[0039] Figure 5 for Figure 2 AA cross-sectional structural diagram.

[0040] Figure 6 for Figure 2 Schematic diagram of the BB cross-sectional structure.

[0041] Figure 7 for Figure 3 Schematic diagram of the cross-sectional structure of CC

[0042] Figure 8 for Figure 4 Schematic diagram of DD cross-section structure.

[0043] In the picture:

[0044] 100. Differential assembly, 200. Ball seat with matching steel ball, 300. Locking and suspension assembly, 400. Outer cylinder assembly, 500. Inner cylinder assembly, 600. Shieldable double core claw structure assembly, 700. Coring drill bit, 1. Toothed upper joint, 2.50 steel ball, 3.50 ball seat, 4. Toothed internal positioning joint, 5. Shear set screw, 6. Toothed lower joint, 7. Gap adjustment internal joint, 8. Gap adjustment external joint, 9. Upper joint, 10. Adjustable gap inner rod, 11.40 steel ball, 12.40 ball seat, 13. Telescopic head, 14. Pressure rod, 15. Positioning joint, 16. Locking block, 17. Internal positioning joint, 18. Pressure seat, 19. Upper shear screw, 20. Upper shear ring, 21. Lower shear screw, 22. Lower shear ring, 23. Bearing box, 24. Suspension shaft, 25. Bearing ring, 26.19 steel ball, 27. Bearing support, 28. Water diversion joint, 29. Upper centralizer, 30. 30 steel ball, 31.30 ball seat, 32. Outer cylinder, 33. Inner cylinder, 34. Lower centralizer, 35. Inner sliding sleeve, 36. Outer sliding sleeve, 37. Lower positioning joint, 38. Lower locking block, 39. Neck sleeve pup joint, 40. Shielding sleeve, 41. Clamp-type core claw, 42. Neck sleeve, 43. Petal-type retractable core claw, 44. Toothed locking block. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0046] Example 1:

[0047] A dual-claw coring tool with a tooth-engaged differential and adjustable gap comprises a differential assembly 100, a ball seat with a matching steel ball 200, a locking and suspension assembly 300, an outer cylinder assembly 400, an inner cylinder assembly 500, a shieldable dual-core claw structure assembly 600, and a coring drill bit 700. The differential assembly 100, the locking and suspension assembly 300, the outer cylinder assembly 400, the shieldable dual-core claw structure assembly 600, and the coring drill bit 700 are sequentially connected from top to bottom via threads, and the upper portion of the inner cylinder assembly 400 is threadedly connected to the locking and suspension assembly 300.

[0048] The shieldable dual core claw assembly 600 consists of an inner sleeve 35, a lower positioning joint 37, an outer sleeve 36, a lower locking block 38, a shield sleeve 40, a neck sleeve sub 39, a clamp-type core claw 41, a neck sleeve 42, and a flap-type retractable core claw 43. The lower portion of the inner barrel assembly 400 is threadedly connected to the inner sleeve 35 and shield sleeve 40. The outer sleeve 36 is threadedly connected to the neck sleeve sub 39, the neck sleeve 42, and the flap-type retractable core claw 43. The outer sleeve 36 and inner sleeve 35 are secured together using shear pins.

[0049] The differential assembly 100 comprises a toothed upper joint 1, a 50 ball seat 3, a toothed internal positioning joint 4, a shear set screw 5, a toothed lower joint 6, a clearance adjustment internal joint 7, a clearance adjustment external joint 8, an adjustable clearance inner rod 10, and a toothed locking block 44. The upper portion of the toothed upper joint 1 is connected to the upper drilling tool via a threaded buckle, while the lower portion of the toothed upper joint 1 is connected to the clearance adjustment external joint 8 via a threaded buckle. The clearance adjustment external joint 8 is connected to the clearance adjustment internal joint 7 via a threaded buckle. The toothed internal positioning joint 4 is connected to the toothed upper joint 1 via a shear set screw 5. The clearance adjustment internal joint 7 is connected to the adjustable clearance inner rod 10 via a threaded buckle.

[0050] The toothed upper joint 1 and the toothed lower joint 6 cooperate with each other through splines, and the toothed locking block 44 controls whether the two move axially; the shape of the spline is not limited to the rectangle listed in this example.

[0051] When the gap adjustment inner joint 7 rotates, the adjustable gap inner rod 10 and the outer cylinder 32 maintain a constant relative position, and the gap adjustment inner joint 7 can move axially relative to the outer cylinder to adjust the axial gap.

[0052] The locking and suspension assembly 300 consists of the ball seat 11 (40), the pressure rod 14, the expansion joint 13, the positioning joint 15, the locking block 16, the inner positioning joint 17, the pressure seat 18, the upper shear ring 20, the upper shear screw 19, the lower shear ring 22, the lower shear screw 21, the bearing box 23, the suspension shaft 24, the bearing ring 25, the steel ball 26 (19), the bearing support 27, the water diversion joint 28, and the ball seat 30 (31). The positioning joint 15 is connected to the clearance adjustment inner joint 7 via a threaded buckle, the positioning joint 15 is connected to the inner positioning joint 17 via the locking block 16, the expansion head 13 is connected to the inner positioning joint 17 via a threaded buckle, the inner positioning joint 17 is connected to the pressure seat 18 via a threaded buckle, the pressure seat 18 is connected to the bearing box 23, and the bearing box 23 is connected to the bearing support 27 via a threaded buckle. The suspension shaft 24 is connected to the water diversion joint 28 via a threaded buckle, and the water diversion joint 28 is connected to the ball seat 30 (31) via a threaded buckle. The bearing box 23, bearing ring 25, bearing support 27, 19 steel ball 26, and suspension shaft 24 are geometrically combined and held together by gravity during use. The upper shear ring 20 is connected to the pressure seat 18 via an upper shear screw 19, while the lower shear ring 22 is connected to the pressure seat 18 via a lower shear screw 21.

[0053] The ball seat supporting steel balls 200 include 30 steel balls 30, 40 steel balls 11, and 50 steel balls 2.

[0054] The diameter of each steel ball is equal to the diameter of the corresponding ball seat. The diameters of 30 steel balls 30, 40 steel balls 11, and 50 steel balls 2 increase in sequence. 30, 40, and 50 do not represent numerical values ​​for steel ball diameters, and steel ball diameters are not limited to the values ​​listed in this example.

[0055] The outer cylinder assembly 400 is composed of an upper joint 9, an upper centralizer 29, an outer cylinder 32, and a lower centralizer 34, and each component is threadedly connected in sequence from top to bottom.

[0056] Before the steel ball 30 is put in and falls into the ball seat 31 to block the mud passage of the inner tube 33, the mud can enter the inner tube 33 through the gap adjustment inner joint 7, the pressure seat 18, the pressure rod 14 and the inner hole of the locking and suspension assembly 300, and then return to the annular space through the inner tube 33 to clean the bottom of the well and flush the inner tube 33.

[0057] After the 40-gauge steel ball 11 is inserted, the pressure rod 14 transmits pressure to the lower shear ring 22, and the lower shear screw 21 is sheared by the shear force. The 40-gauge steel ball 11, 40-gauge ball seat 12, pressure rod 14, upper shear ring 20, and lower shear ring 22 fall downward. The inner diameter of the positioning joint 15 is smaller than the outer diameter of the 40-gauge ball seat 12, forming a circulation path for the mud, achieving the purpose of pressure relief.

[0058] Through the differential assembly, the shielding sleeve 40 is lifted up to expose the clamp-type core claw 41, completing the core pulling and cutting process.

[0059] The outer sliding sleeve 36 has two evenly distributed keyways that cooperate with the lower locking block 38. The inner surface of the lower locking block 38 cooperates with the shielding sleeve 40, and the outer surface cooperates with the lower positioning joint 37, and its outer diameter is larger than the inner diameter of the lower positioning joint 37.

[0060] In this embodiment, when cutting the core, two core cutting methods, namely, pressing down and pulling up, are simultaneously adopted: the differential assembly 100 and the locking and suspension assembly 300 first press down to cut the shear pins, and the petal-type retractable core claws 43 are retracted, and then pulled up to expose the clamp-type core claws 41, and the core is pulled up to cut.

[0061] When pulling up the core, the differential assembly 100 drives the inner sleeve 35 and the outer sleeve 36 to move up at the same time. After the lower locking block 38 touches the lower positioning joint 37, the inner sleeve 35 continues to be lifted up, and the shielding sleeve 40 is lifted out of the clamp-type core claw 41.

[0062] A 50mm steel ball 2 is inserted and falls into the 50mm ball seat 3. Pressure is transmitted through the 50mm steel ball 2 to the 50mm ball seat 3, which in turn transmits pressure to the toothed internal positioning joint 4. The shear fixing screw 5 is sheared by the shear force. The gap adjustment internal joint 7 then falls, and the toothed locking block 44 loses its resistance and falls. The toothed upper joint 1 and the toothed lower joint 6 lose their axial restraint and can undergo axial relative movement.

[0063] Example 2:

[0064] A dual-claw coring tool with a toothed differential and adjustable clearance includes a differential assembly, a locking and suspension assembly, an outer barrel assembly, an inner barrel assembly, a shieldable dual-core claw assembly, a coring drill bit, and a ball seat with matching steel balls. The differential mechanism includes a toothed upper joint, a toothed lower joint, a toothed internal positioning joint, a 50° ball seat, a shear set screw, a toothed locking block, and a clearance adjustment device. The clearance adjustment device includes an external clearance adjustment joint, an internal clearance adjustment joint, and an adjustable clearance inner rod. The upper portion of the toothed upper joint is connected to the upper drill bit via a threaded buckle, while the lower portion of the toothed upper joint is connected to the external clearance adjustment joint via a threaded buckle. The external clearance adjustment joint and the internal clearance adjustment joint are connected via a threaded buckle. The toothed upper joint and the toothed lower joint engage with each other via a spline, and the toothed locking block prevents axial movement between them. The internal positioning joint and the toothed upper joint are connected via a shear set screw. The internal clearance adjustment joint and the adjustable clearance inner rod are connected via a threaded buckle.

[0065] The locking and suspension assembly includes a 40-degree ball seat, a pressure rod, an expansion joint, a locating joint, a locking block, an internal locating joint, a pressure seat, an upper shear ring, an upper shear screw, a lower shear ring, a lower shear screw, a bearing box, a suspension shaft, a bearing ring, a 19-degree steel ball, a bearing support, a water diverter joint, and a 30-degree ball seat. The locating joint connects to the internal clearance adjustment joint via a threaded buckle, the locating joint connects to the internal locating joint via a locking block, the expansion joint connects to the internal locating joint via a threaded buckle, the internal locating joint connects to the pressure seat via a threaded buckle, the pressure seat connects to the bearing box, the bearing box connects to the bearing support via a threaded buckle, the suspension shaft connects to the water diverter joint via a threaded buckle, and the water diverter joint connects to the 30-degree ball seat via a threaded buckle. The bearing box, bearing ring, bearing support, 19-degree steel ball, and suspension shaft are geometrically combined, and the tool is held in place by gravity. The upper shear ring connects to the pressure seat via an upper shear screw, and the lower shear ring connects to the pressure seat via a lower shear screw.

[0066] The outer tube assembly includes an upper joint, an upper centralizer, an outer tube, a lower centralizer, an outer tube lower fitting joint 1, and an outer tube lower fitting joint 2. The components are threadedly connected in sequence from top to bottom.

[0067] The shieldable dual core claw assembly consists of an inner sleeve, a lower locating joint, an outer sleeve, a lower locking block, a shield sleeve, a necking sleeve sub, a clamp-type core claw, a necking sleeve, and a flap-type retractable core claw. The inner and outer sleeves are connected by shear pins, the inner sleeves by threaded fasteners, and the outer sleeve by threaded fasteners. The outer sleeve has two evenly spaced keyways that mate with the lower locking block. The lower locking block's inner surface mates with the shield sleeve, while its outer surface mates with the shield sleeve. Its outer diameter is larger than the inner diameter of the lower locating joint. The clamp-type core claw is located within the annular cavity formed by the necking sleeve and shield sleeve and is capable of axial movement. The flap-type retractable core claw is connected to the necking sleeve by threaded fasteners.

[0068] The matching steel balls for the ball seat include 30 steel balls, 40 steel balls, and 50 steel balls.

[0069] The differential assembly, the locking and suspension assembly, the outer cylinder assembly, the shieldable double core claw structure assembly, and the coring drill bit are sequentially connected from top to bottom through threads, and the upper part of the inner cylinder assembly is connected to the locking and suspension assembly through threads.

[0070] In this embodiment, steel balls are not introduced before drilling. After reaching the bottom of the well, a pump is activated to circulate mud. Mud then flows through the inner holes of the clearance adjustment nipple, pressure seat, pressure rod, and locking and suspension assembly, entering the inner barrel and then returning to the annular space. This method not only cleans the well bottom but also flushes the inner barrel. Once the mud has been treated and the bottom is clean, a 30-gauge steel ball is introduced. The 30-gauge steel ball falls into the 30-gauge ball seat, blocking the mud passage in the inner barrel, and coring drilling begins.

[0071] During coring drilling, the clamp-type core claw is located between the shielding sleeve and the necking sleeve and does not directly contact the core.

[0072] When coring is completed and the core needs to be cut, both downward pressure and upward pull are used. A 40-gauge steel ball is inserted and falls into the 40-gauge ball seat. Pressure is transmitted through the 40-gauge steel ball to the 40-gauge ball seat, which in turn transmits the pressure to the pressure rod, which in turn transmits the pressure to the upper shear ring. The upper shear screw is subjected to shear force. When the shear force on the upper shear screw exceeds the shear strength, the upper shear screw is sheared, and the 40-gauge steel ball, 40-gauge ball seat, pressure rod, and upper shear ring fall. The pressure rod loses its resistance to the locking block, causing it to slide out. The locking and suspension assembly and inner barrel are then lowered, forcing the retractable petal-shaped core claws to retract along the conical surface of the core bit's inner cavity, cutting and encapsulating the core, achieving the goal of coring in soft formations.

[0073] Because the 40-gauge steel ball blocks the flow, the pressure rod continues to transmit pressure to the lower shear ring, subjecting the lower shear screw to shear force. When the shear force exceeds the shear strength, the lower shear screw shears. The 40-gauge steel ball, 40-gauge ball seat, pressure rod, upper shear ring, and lower shear ring descend, and the inner diameter of the locating joint becomes smaller than the outer diameter of the 40-gauge ball seat, creating a slurry circulation path and achieving pressure relief.

[0074] After unloading the pressure, a 50 steel ball is put in, and the 50 steel ball falls into the 50 ball seat. The pressure is transmitted to the 50 ball seat through the 50 steel ball, and the 50 ball seat transmits the pressure to the toothed inner positioning joint. The shear fixing screw is subjected to shear force. When the shear force borne by the shear fixing screw exceeds the shear strength, the shear fixing screw is sheared. The gap adjustment inner joint falls, and the toothed locking block loses its resistance and falls. The toothed upper joint and the toothed lower joint can undergo axial relative movement. When lifting the tool, the toothed upper joint, the gap adjustment outer joint, the gap adjustment inner joint, the adjustable gap inner rod, the locking and suspension assembly, the inner cylinder assembly, and the shielding sleeve move up to expose the clamp-type core claw. The differential assembly drives the inner sleeve and the outer sleeve to move up at the same time. After the lower locking block touches the lower positioning joint, the inner sleeve continues to be lifted up, and the shielding sleeve is lifted out of the clamp-type core claw to complete the core pulling and cutting, thereby achieving the purpose of coring in hard formations.

[0075] Example 3:

[0076] Refer to the attached Figure 1 、 Figure 2 and Figure 5 The present invention provides a dual-structured claw coring tool with a tooth-embedded differential and adjustable gap, comprising a differential assembly 100, a locking and suspension assembly 300, an outer cylinder assembly 400, an inner cylinder assembly 500, a shieldable dual-core claw structure assembly 600, a coring drill bit 700, and a ball seat matching steel ball 200.

[0077] The differential assembly 100, the locking and suspension assembly 300, the outer cylinder assembly 400, the shieldable double core claw structure assembly 600, and the coring drill bit 700 are sequentially connected from top to bottom through threads, and the upper part of the inner cylinder assembly 400 is connected to the locking and suspension assembly 300 through threads.

[0078] Among them, the differential assembly 100 includes a toothed upper joint 1, a toothed lower joint 6, a toothed inner positioning joint 4, a 50 ball seat 3, a shear fixing screw 5, a toothed locking block 44, a clearance adjustment inner joint 7, a clearance adjustment outer joint 8, and an adjustable clearance inner rod 10.

[0079] The upper portion of the toothed upper joint 1 is connected to the upper drilling tool via a threaded connection, while the lower portion of the toothed upper joint 1 is connected to the gap adjustment external joint 8 via a threaded connection. The gap adjustment external joint 8 is also connected to the gap adjustment internal joint 7 via a threaded connection. The toothed upper joint 1 and the toothed lower joint 6 are connected via a spline, with the toothed locking block 44 preventing axial movement between the two. The toothed internal positioning joint 4 is connected to the toothed upper joint 1 via a shear set screw 5.

[0080] The gap adjustment inner joint 7 is connected to the adjustable gap inner rod 10 by a threaded buckle. When the gap adjustment inner joint 7 rotates, the adjustable gap inner rod 10 and the outer cylinder 32 maintain a constant relative position, and the gap adjustment inner joint 7 can move axially relative to the outer cylinder to adjust the axial gap.

[0081] Refer to the attached Figure 3 The locking and suspension assembly 300 includes 40 ball seats 12, pressure rods 14, telescopic heads 13, positioning joints 15, locking blocks 16, inner positioning joints 17, pressure seats 18, upper shear rings 20, upper shear screws 19, lower shear rings 22, lower shear screws 21, bearing boxes 23, suspension shafts 24, bearing rings 25, 19 steel balls 26, bearing supports 27, water diversion joints 28, and 30 ball seats 31.

[0082] The positioning joint 15 is connected to the clearance adjustment inner joint 7 via a threaded buckle. The positioning joint 15 is connected to the inner positioning joint 17 via a locking block 16. The pressure rod 14 extends into the inner hole of the inner positioning joint 17 to radially limit the locking block 16. The telescopic head 13 is connected to the inner positioning joint 17 via a threaded buckle. The inner positioning joint 17 is connected to the pressure seat 18 via a threaded buckle. The pressure seat 18 is connected to the bearing box 23 via a threaded buckle. The bearing box 23 is connected to the bearing support 27 via a threaded buckle. The suspension shaft 24 is connected to the water diversion joint 28 via a threaded buckle. The water diversion joint 28 is connected to the ball seat 30 via a threaded buckle. The bearing box 23, bearing ring 25, bearing support 27, 19 steel ball 26, and suspension shaft 24 are combined together through their own geometric shapes. When the tool is used, it is compressed by gravity. The bearing box 23 and bearing support 27 axially limit the bearing ring 25 and 19 steel ball 26. The suspension shaft 24 is suspended on the bearing ring 25. The upper shear ring 20 and the lower shear ring 22 are installed in the pressure seat 1. The upper shear ring 20 is connected to the pressure seat 18 through the upper shear screw 19, and the lower shear ring 22 is connected to the pressure seat 18 through the lower shear screw 21.

[0083] Refer to the attached Figure 3 and Figure 4 The outer cylinder assembly 400 includes an upper joint 9, an upper centralizer 29, an outer cylinder 32, and a lower centralizer 34, and each component is threadedly connected in sequence from top to bottom.

[0084] Refer to the attached Figure 4 The shieldable dual core claw structure assembly 600 comprises an inner sleeve 35, a lower positioning joint 37, an outer sleeve 36, a lower locking block 38, a shielding sleeve 40, a necking sleeve sub 39, a clamp-type core claw 41, a necking sleeve 42, and a flap-type retractable core claw 43. The lower portion of the inner barrel assembly 400 is threadedly connected to the inner sleeve 35 and shielding sleeve 40. The outer sleeve 36 is threadedly connected to the necking sleeve sub 39, the necking sleeve 42, and the flap-type retractable core claw 43. The inner sleeve 35 and outer sleeve 36 are connected by shear pins, the inner sleeve 35 and shielding sleeve 40 are connected by threaded buckles, and the outer sleeve 36 and necking sleeve sub 39 are connected by threaded buckles. The outer sleeve 36 has two evenly spaced keyways that mate with the lower locking block 38. The inner surface of the lower locking block 38 engages with the shielding sleeve 40, while its outer surface engages with the lower positioning joint 37. Its outer diameter is larger than the inner diameter of the lower positioning joint 37. A clamping core claw 41 is located within the annular cavity formed by the necking sleeve 42 and the shielding sleeve 40 and is capable of axial movement. A retractable petal-shaped core claw 43 is connected to the necking sleeve 42 via a threaded fastener.

[0085] Refer to the attached Figure 2 and Figure 3 The ball holders are equipped with steel balls 200, including 30 steel balls 30, 40 steel balls 11, and 50 steel balls 20. The diameters of the steel balls are all equal to the diameters of the corresponding ball holders. The diameters of the 30 steel balls 30, 40 steel balls 11, and 50 steel balls 2 increase in order. The numbers 30, 40, and 50 do not represent numerical values ​​for the steel ball diameters; the steel ball diameters are not limited to the values ​​listed in this example.

[0086] Refer to the attached Figure 1 The differential assembly 100, the locking and suspension assembly 300, the outer cylinder assembly 400, the shieldable double core claw structure assembly 600, and the coring drill bit 700 are sequentially connected from top to bottom through threads, and the upper part of the inner cylinder assembly 500 is connected to the locking and suspension assembly 300 through threads.

[0087] The above scheme further includes:

[0088] Before drilling, steel balls are not introduced. After reaching the bottom of the well, the pump is turned on to circulate the mud. The mud then flows through the inner hole of the clearance adjustment nipple 7, the pressure seat 18, the pressure rod 14, and the locking and suspension assembly 300, into the inner tube 33, and then returns from the inner tube 33 to the annular space. This not only cleans the bottom of the well but also rinses the inner tube 33. Once the mud has been treated and the bottom of the well is clean, steel balls 30 are introduced. They fall into the ball seats 31, blocking the mud passages in the inner tube 33, and coring drilling begins.

[0089] During coring drilling, the clamp-type core claw 41 is located between the shielding sleeve 40 and the necking sleeve 42 and does not directly contact the core.

[0090] When coring is completed and the core needs to be cut, both downward pressure and upward pull are used. A 40-gauge steel ball 11 is inserted and falls into the 40-gauge ball seat 12. Pressure is transmitted through the 40-gauge steel ball 11 to the 40-gauge ball seat 12. The 40-gauge ball seat 12 transmits pressure to the 40-gauge ball seat 12, which in turn transmits pressure to the pressure rod 14. The pressure rod 14 transmits pressure to the upper shear ring 20, subjecting the upper shear screw 19 to shear force. When the shear force on the upper shear screw 19 exceeds the shear strength, the upper shear screw 19 is sheared. The 40-gauge steel ball 11, 40-gauge ball seat 12, pressure rod 14, and upper shear ring 20 fall downward, and the pressure rod 14 loses its resistance to the locking block 16, causing it to slide out and the locating joint 15 to disengage from the inner locating joint 17. The locking and suspension assembly 300 and inner barrel 33 are then driven downward, forcing the petal-shaped retractable core claw 43 to retract along the conical surface of the coring drill bit 700, cutting and enveloping the core, achieving the purpose of coring in soft formations.

[0091] Because the 40 steel ball 11 blocks the flow, the pressure rod 14 continues to transmit pressure to the lower shear ring 22, subjecting the lower shear screw 21 to shear force. When the shear force on the lower shear screw 21 exceeds the shear strength, the lower shear screw 21 is sheared. The 40 steel ball 11, 40 ball seat 12, pressure rod 14, upper shear ring 20, and lower shear ring 22 fall downward. The inner diameter of the positioning joint 15 is smaller than the outer diameter of the 40 ball seat 12, forming a slurry circulation path and achieving pressure relief.

[0092] After the pressure is released, a 50 steel ball 2 is inserted and falls into the 50 ball seat 3. The pressure is transmitted to the 50 ball seat 3 through the 50 steel ball 2, and the 50 ball seat 3 transmits the pressure to the toothed internal positioning joint 4. The shear fixing screw 5 is subjected to shear force. When the shear force on the shear fixing screw 5 exceeds the shear strength, the shear fixing screw 5 is sheared. The gap adjustment internal joint 7 falls, and the toothed locking block 44 loses its resistance and falls. The toothed upper joint 1 and the toothed lower joint 6 can undergo axial relative movement. During coring drilling, the clamp-type core claw 41 is between the shielding sleeve 40 and the necking sleeve 42 and does not directly contact the core. When cutting the core and raising the coring tool, the toothed upper joint 1, the gap adjustment external joint 8, the gap adjustment internal joint 7, the adjustable gap inner rod 10, the locking and suspension assembly 300, the inner cylinder assembly 500, and the shielding sleeve 40 move upward to expose the clamp-type core claw 41. The differential assembly 100 drives the inner sleeve 35 and the outer sleeve 36 to move upward at the same time. After the lower locking block 38 touches the lower positioning joint 37, the inner sleeve 35 is further lifted, and the shielding sleeve 40 is lifted out of the clamp-type core claw 41, completing the core pulling and cutting, achieving the purpose of coring in hard formations.

[0093] The advantages of the present invention are: structurally avoiding repeated core cutting caused by deep-water operations, preventing the core from being unable to form a column; providing a universal coring tool suitable for soft to hard formations when the lithology of the formation is unknown; and having high reliability when multiple barrels are continuously coring in deep-water operations.

[0094] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A dual-jaw coring tool with differentially adjustable tooth gap, characterized by: It includes a differential assembly, a ball seat supporting steel ball, a locking and suspension assembly, an outer cylinder assembly, an inner cylinder assembly, a shieldable double core claw structure assembly, and a core drill bit; the differential assembly, the locking and suspension assembly, the outer cylinder assembly, the shieldable double core claw structure assembly, and the core drill bit are connected in sequence from top to bottom, and the upper part of the inner cylinder assembly is connected to the locking and suspension assembly; the shieldable double core claw structure assembly includes an inner sleeve, a lower positioning joint, an outer sleeve, a lower locking block, a shielding sleeve, a necking sleeve short section, a clamp-type core claw, a necking sleeve, and a petal-type retractable core claw; the lower part of the inner cylinder assembly is connected to the inner sleeve , the shielding sleeve is connected in sequence by threads; the outer sliding sleeve is connected to the necking sleeve short section, the necking sleeve, and the flap-type retractable core claw are connected in sequence by threads; the inner sliding sleeve is connected to the outer sliding sleeve by a shear pin, the inner sliding sleeve is connected to the shielding sleeve by a threaded buckle, and the outer sliding sleeve is connected to the necking sleeve short section by a threaded buckle; the outer sliding sleeve has two evenly distributed key slots that cooperate with the lower locking block; the inner surface of the lower locking block cooperates with the shielding sleeve, and the outer surface cooperates with the lower positioning joint, and its outer diameter is larger than the inner diameter of the lower positioning joint; the clamp core claw is located in the annular cavity formed by the necking sleeve and the shielding sleeve, and can move axially; the flap-type retractable ... The core reduction claw and the neck reduction sleeve are connected by a threaded buckle; the differential assembly includes a toothed upper joint, a 50 ball seat, a toothed inner positioning joint, a shear fixing screw, a toothed lower joint, a gap adjustment inner joint, a gap adjustment outer joint, an adjustable gap inner rod, and a toothed locking block; a 50 steel ball is put in, and the 50 steel ball falls into the 50 ball seat, and the pressure is transmitted to the 50 ball seat through the 50 steel ball, and the 50 ball seat transmits the pressure to the toothed inner positioning joint; the upper part of the toothed upper joint is connected to the upper drilling tool by a threaded buckle, and the lower part of the toothed upper joint is connected to the gap adjustment outer joint by a threaded buckle; the gap adjustment outer joint The toothed inner joint is connected to the gap adjustment inner joint by a threaded buckle; the toothed inner positioning joint is connected to the toothed upper joint by a shear fixing screw; the gap adjustment inner joint is connected to the adjustable gap inner rod by a threaded buckle; the toothed upper joint and the toothed lower joint cooperate with each other through a spline, and a toothed locking block is provided between the toothed upper joint and the toothed lower joint, which limits the axial position of the toothed upper joint and the toothed lower joint; the outer cylinder assembly includes an outer cylinder, and when the gap adjustment inner joint rotates, the adjustable gap inner rod and the outer cylinder maintain a constant relative position, and the gap adjustment inner joint can move axially relative to the outer cylinder.

2. The dual-jaw coring tool with differentially adjustable gap according to claim 1, characterized in that: The shieldable double core claw structure assembly includes an inner sliding sleeve, a lower positioning joint, an outer sliding sleeve, a lower locking block, a shielding sleeve, a neck sleeve short section, a clamp-type core claw, a neck sleeve, and a flap-type retractable core claw; the lower part of the inner cylinder assembly is connected with the inner sliding sleeve and the shielding sleeve in sequence; the outer sliding sleeve is connected with the neck sleeve short section, the neck sleeve, and the flap-type retractable core claw in sequence; the outer sliding sleeve and the inner sliding sleeve are connected and fixed by shear pins.

3. The dual-jaw coring tool with differentially adjustable gap according to claim 2, characterized in that: The locking and suspension assembly includes a 40 ball seat, a pressure rod, a telescopic head, a positioning joint, a locking block, an inner positioning joint, a pressure seat, an upper shear ring, an upper shear screw, a lower shear ring, a lower shear screw, a bearing box, a suspension shaft, a bearing ring, a 19 steel ball, a bearing support, a water diversion joint, and a 30 ball seat; when a 40 steel ball is put in, the 40 steel ball falls into the 40 ball seat, and the pressure is transmitted to the 40 ball seat through the 40 steel ball, and the 40 ball seat transmits the pressure to the pressure rod, and the pressure rod transmits the pressure to the upper shear ring; the positioning joint and the clearance adjustment inner joint are connected by a threaded buckle, and the positioning joint and the inner fixed joint are connected by a threaded buckle. The positioning joint is connected by a locking block, the expansion head is connected to the inner positioning joint by a threaded buckle, the inner positioning joint is connected to the pressure seat by a threaded buckle, the pressure seat and the bearing box, the bearing box and the bearing support are connected by a threaded buckle, the suspension shaft and the water diversion joint are connected by a threaded buckle, and the water diversion joint and the 30 ball seat are connected by a threaded buckle; the bearing box, bearing ring, bearing support, 19 steel balls, and suspension shaft are combined together through their own geometric shapes, and the tool is tightened by gravity when used; the upper shear ring and the pressure seat are connected by the upper shear screw, and the lower shear ring and the pressure seat are connected by the lower shear screw.

4. The dual-jaw coring tool with differentially adjustable gap according to claim 3, characterized in that: The matching steel balls for the ball seat include 30 steel balls, 40 steel balls, and 50 steel balls.

5. The dual-jaw coring tool with differentially adjustable gap according to claim 4, characterized in that: The diameter of the steel balls is equal to the diameter of the matching ball seats, and the diameters of 30 steel balls, 40 steel balls, and 50 steel balls increase in sequence.

6. The dual-jaw coring tool with differentially adjustable gap according to claim 5, characterized in that: The outer cylinder assembly includes an upper joint, an upper centralizer, an outer cylinder, and a lower centralizer which are connected in sequence from top to bottom.

7. The dual-jaw coring tool with differentially adjustable gap according to claim 6, characterized in that: The outer sliding sleeve is provided with two evenly distributed key slots cooperating with the lower locking block; the inner surface of the lower locking block cooperates with the shielding sleeve, and the outer surface cooperates with the lower positioning joint, and the outer diameter of the lower locking block is larger than the inner diameter of the lower positioning joint.

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