A directional coring tool

Abstract

This patent discloses a directional coring tool. The suspension joint, suspension assembly, upper outer barrel centralizer, outer core barrel, lower outer barrel centralizer, inner core barrel, pressure sleeve, core catcher, and coring bit are sequentially connected by threads. The inner core barrel adopts a pin suspension method, and core cutting is carried out by mechanical pressure, which is safe and reliable, and the core cutting display can be observed on the ground. After coring drilling is completed, the drill string is lowered smoothly, and the pressure seat transfers the pressure to the pin, and the pin is cut off. The suspension assembly, pressure seat, and inner core barrel drop down, forcing the core catcher to contract along the conical surface of the inner cavity of the coring bit, cutting and enclosing the core to achieve the purpose of coring. The core catcher adopts the form of main and secondary cutting blades, which are triangular hard alloy cutter bars, solving the problems existing in the prior art that two centralizing blocks with flat tops at the two tops can only play a centralizing role and cannot stop rotation, and the cutting blades are easy to cut out spiral curves or left and right swing lines on the core surface and cannot cut out a straight line.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas drilling operations, and particularly to a directional coring tool for the field of oil and gas exploration and development and a method for operating using this coring tool. Background Art

[0002] With the development of domestic and foreign drilling technologies and the increase in the construction of directional wells and horizontal wells, the requirements for corresponding drilling coring technologies are also getting higher and higher. Conventional, closed, and original directional well coring tools can no longer fully meet the requirements of the geological department for oil and gas reservoir evaluation during operations.

[0003] The core taken by a conventional coring tool can only reflect the formation rock structure, physical properties, and the depth and thickness of the reservoir.

[0004] A closed coring tool can reflect the original oil and water saturation of the formation, but it cannot restore the taken core to the true state in the formation.

[0005] The core taken by the original directional well coring tool cannot obtain the formation fracture trend, rock layer trend and dip angle, and formation anisotropy. Summary of the Invention

[0006] The purpose of the present invention is to provide a directional coring tool for the deficiencies in the prior art.

[0007] The technical solution is as follows:

[0008] A directional coring tool includes a tool body composed of a positioning joint (1), an upper outer barrel centralizer (7), an outer core barrel (8), a lower outer barrel centralizer (10), and a coring bit (14) that are sequentially threadedly connected.

[0009] Inside the tool body, a pressure-bearing seat (2), a suspension joint (5), a suspension assembly (6), an inner core barrel (9), a pressure sleeve (11), and a core catcher (13) are sequentially installed from top to bottom; the pressure-bearing seat (2) is sleeved inside the positioning joint (1) through shear pins.

[0010] The upper end of the suspension joint (5) is sleeved between the lower ends of the positioning joint (1) and the pressure-bearing seat (2). There is a clearance fit among the lower end of the positioning joint (1), the upper end of the suspension joint (5), and the lower end of the pressure-bearing seat (2). Radial through-holes are provided at the lower end of the positioning joint (1), the upper end of the suspension joint (5), and the lower end of the pressure-bearing seat (2). The diameter of the radial through-hole is larger than the diameter of the first steel ball (4). The ball sleeve (3) is threadedly connected to the outer end of the radial through-hole of the positioning joint (1). The positions of the radial through-holes at the lower end of the positioning joint (1) and the upper end of the suspension joint (5) correspond to each other. The radial through-hole at the lower end of the pressure-bearing seat (2) is higher than the radial through-hole at the upper end of the suspension joint (5). The first steel ball (4) is located between the radial through-holes at the lower end of the positioning joint (1) and the upper end of the suspension joint (5), axially fixing the positioning joint (1) and the suspension joint (5).

[0011] The suspension assembly (6) is rotatably sleeved on the lower end of the suspension joint (5) through a bearing assembly;

[0012] The lower end of the positioning joint (1) is threadedly connected to the upper end of the upper outer barrel centralizer (7). The lower end of the upper outer barrel centralizer (7) is threadedly connected to the upper end of the outer core barrel (8). The lower end of the outer core barrel (8) is threadedly connected to the upper end of the lower outer barrel centralizer (10). The lower end of the lower outer barrel centralizer (10) is threadedly connected to the upper end of the core bit (14);

[0013] The lower end of the water distribution joint (6-6) is threadedly connected to the inner core barrel (9) through an external thread. The lower end of the inner core barrel (9) is threadedly connected to the upper end of the pressure sleeve (11). The lower end of the pressure sleeve (11) is threadedly connected to the upper end of the core catcher (13);

[0014] A limiting step is provided between the lower end of the pressure sleeve (11) and the upper end of the core catcher (13). The adjusting ring (12) is located between the limiting steps, and its axial movement is restricted by the extrusion between the pressure sleeve (11) and the core catcher (13).

[0015] Furthermore, the suspension assembly (6) includes a bearing assembly, a suspension shaft (6-2), a water distribution joint (6-6), and a ball seat (6-7);

[0016] The bearing assembly includes a bearing housing (6-1), a bearing support (6-5), and a second steel ball (6-3);

[0017] The lower end of the suspension joint (5) is threadedly connected to the upper end of the bearing housing (6-1). The inner thread at the lower end of the bearing housing (6-1) is threadedly connected to the outer thread at the upper end of the bearing support (6-5). The outer thread at the lower end of the suspension shaft (6-2) is threadedly connected to the inner thread at the upper end of the water distribution joint (6-6). The inner thread at the lower end of the water distribution joint (6-6) is threadedly connected to the outer thread at the upper end of the ball seat (6-7). The suspension shaft (6-2) is rotatably sleeved in the bearing housing (6-1) through the bearing assembly;

[0018] The inner wall of the lower end of the bearing box (6-1) and the outer wall of the suspension shaft (6-2) are provided with limiting steps, and two opposite annular grooves are formed between the limiting steps and the upper end surfaces of the bearing support (6-5) and the water distribution joint (6-6) respectively. The bearing ring (6-4) is sleeved in the annular groove, and the second steel ball (6-3) is embedded in the bearing ring (6-4).

[0019] Furthermore, the suspension assembly (6) includes a bearing assembly, a suspension shaft (6-2), a water distribution joint (6-6), and a ball seat (6-7).

[0020] The bearing assembly includes a bearing box (6-1), a first thrust bearing (18-3), and a bearing support (6-5).

[0021] The lower end of the suspension joint (5) is threadedly connected to the upper end of the bearing box (6-1), and the inner thread at the lower end of the bearing box (6-1) is threadedly connected to the outer thread at the upper end of the bearing support (6-5); the outer thread at the lower end of the suspension shaft (6-2) is threadedly connected to the inner thread at the upper end of the water distribution joint (6-6), and the inner thread at the lower end of the water distribution joint (6-6) is threadedly connected to the outer thread at the upper end of the ball seat (6-7); the suspension shaft (6-2) is rotatably sleeved in the bearing box (6-1) through the bearing assembly.

[0022] The inner wall of the lower end of the bearing box (6-1) and the outer wall of the suspension shaft (6-2) are provided with limiting steps, and two opposite annular grooves are formed between the limiting steps and the upper end surfaces of the bearing support (6-5) and the water distribution joint (6-6) respectively. The first thrust bearing (18-3) is sleeved in the annular groove.

[0023] Furthermore, the bearing assembly further includes a second thrust bearing (18-4). There are two limiting steps on the outer wall of the suspension shaft (6-2), and one of the limiting steps divides the annular groove on the outer wall of the suspension shaft (6-2) into upper and lower parts. The second thrust bearing (18-4) is installed in the lower annular groove.

[0024] Furthermore, an upper roller centering bearing (19-1) and a lower roller centering bearing (19-2) are further included. A limiting step is provided on the outer part of the upper end of the upper outer cylinder centering device (7) to form an annular groove with the lower end surface of the water distribution joint (6-6); a limiting step is provided on the outer part of the core barrel bit (14) to form an annular groove with the outer wall of the core catcher (13); the upper roller centering bearing (19-1) and the lower roller centering bearing (19-2) are respectively installed in the annular grooves.

[0025] Furthermore, a core orientation cutter is welded on the inner wall of the lower end of the core catcher (13).

[0026] Furthermore, the core orientation cutter includes a left centering cutter (13-1), a right centering cutter (13-2), and a main cutter (13-3) which are arranged at unequal circumferential intervals.

[0027] Furthermore, the core orientation cutter is a triangular cemented carbide cutter bar.

[0028] Furthermore, the upper end of the pressure-bearing seat (2) is provided with an extended limiting step whose diameter is larger than the inner diameter of the suspension joint (5). When the shear pin is cut off and the pressure-bearing seat (2) drops, the limiting step at the upper end of the pressure-bearing seat (2) is caught on the upper end of the suspension joint (5), and the radial through holes on the pressure-bearing seat (2) and the radial through holes on the suspension joint (5) are opposite to each other.

[0029] Furthermore, during coring, the shear pin is cut off, the pressure-bearing seat (2) drops, the radial through holes of the pressure-bearing seat (2) and the radial through holes of the suspension joint (5) are opposite to each other, the first steel ball (4) rolls out of the ball sleeve (3), and the suspension assembly (6), the pressure-bearing seat (2), and the inner core barrel (9) drop downwards, forcing the core catcher (13) to contract along the inner cavity conical surface of the coring bit (14), cutting and enclosing the core, so as to achieve the purpose of coring.

[0030] Furthermore, three spring cutters (16) are installed in the pressure sleeve (11). The spring cutters (16) protrude from the inner wall of the pressure sleeve (11). The spring cutters (16) include cutter teeth (16-1) and spring pieces (16-2); the cutter teeth (16-1) are welded to one end of the spring piece (16-2), and the other end of the spring piece (16-2) is provided with a rivet hole; the spring cutters (16) are connected to the pressure sleeve (11) through rivets.

[0031] Furthermore, the cutter teeth (16-1) are made of cemented carbide as the processing material.

[0032] The beneficial effects of the present invention are as follows:

[0033] By using the scoring knife on the core catcher and the ground reset instrument, the formation fractures and occurrence can be visually observed from the core; during on-site core fracture measurement and interpretation, the core is drilled not long ago, the influence of stress release deformation on the core is small, the influence of human damage is small, and the measurement result error is small; geological data such as formation strike, dip angle, formation deposition direction, formation permeability direction, well deviation angle, and wellbore azimuth can be effectively obtained.

[0034] The tool adopts a pressurized core cutting mechanism with a telescopic function, which is especially suitable for core cutting operations in soft formations and can ensure the core recovery rate. The inner core barrel adopts a pin suspension method, and mechanical pressure is applied for core cutting, which is safe and reliable, and the core cutting display can be observed on the ground. The inner barrel adopts large balls and a suspension bearing without a cartridge clip, which rotates flexibly and has a long service life. The core catcher for core cutting is connected to the inner barrel in a reverse buckle manner, ensuring that the core catcher does not reverse buckle during drilling. The core catcher adopts the form of main and auxiliary cutters, which are triangular hard alloy cutter bars, solving the problem in the prior art that two centralizers with flat tops at the top can only play a centralizing role and cannot stop rotation, and the cutter is easy to cut spiral curves or left and right swing lines on the core surface and cannot cut a straight line.

[0035] Before running in the hole, the valve steel ball is not installed in the present invention. After running to the bottom of the well, the pump is started to circulate the mud. At this time, the mud enters the inner barrel through the positioning joint, pressure-bearing seat, suspension joint and the inner hole of the suspension assembly, and then returns to the annular space through the inner core barrel. In this way, the bottom of the well can be cleaned and the inner core barrel can be flushed. After the mud has treated the bottom of the well to be clean, the valve steel ball is put in, and the valve steel ball falls into the ball seat, blocking the mud passage of the inner core barrel, and then coring drilling starts.

[0036] During coring drilling, the cutter on the core catcher continuously scratches on the core before the core changes its original state, leaving a marking groove, and an electronic multi-point measuring instrument is used to measure the azimuth angle of the main cutter mark, the well inclination angle and the well inclination azimuth angle while drilling.

[0037] After the coring drilling is completed, the drill string is lowered and pressurized. The weight of the drill string is transmitted to the pressurizing device through the valve steel ball, and the pressurizing device transmits the pressure to the pressure-bearing seat. When the pressure borne by the pin exceeds the shear strength, the pin is cut off, the pressure-bearing seat drops, the radial through hole of the pressure-bearing seat is opposite to the radial through hole of the suspension joint, and the 30 steel balls roll out of the ball sleeve and fall into the cavity formed by the suspension assembly and the valve steel ball through the radial through hole of the pressure-bearing seat. The suspension assembly, the pressure-bearing seat and the inner core barrel are dropped, forcing the core catcher to contract along the conical surface of the inner cavity of the coring bit, cutting and wrapping the core, achieving the purpose of coring.

[0038] After the core is taken out, on the basis of the azimuth angle, well inclination angle of the cored well and the core orientation mark and the orientation mark azimuth angle that have been obtained, the core with the orientation mark is restored to the original state of the core in the well on the instrument, and then the bedding plane on the core column is measured to obtain the formation attitude parameters.

[0039] The present invention adopts a core-cutting mechanism with a pitching and pressurizing function that has a telescopic function, and is particularly suitable for core-cutting operations in soft formations, which can ensure the core recovery rate. The inner core barrel adopts a pin suspension method, and mechanical pressure is applied for core cutting, which is safe and reliable, and the core-cutting display can be observed on the ground. The suspension assembly adopts large marbles and a suspension bearing without a cartridge, allowing mud to pass through, which plays a role in cooling and lubrication. The structure is simple, the rotation is flexible, and the service life is long. The core catcher for core cutting is connected to the inner barrel in a reverse buckle manner, ensuring that the core catcher does not reverse buckle during the drilling process. The outer core barrel is made of high-strength thick-walled seamless steel pipe and is equipped with upper and lower centralizers, which have high strength and good stability, are beneficial to improving the core recovery rate, and prolong the service life of the core bit. In addition to the steel inner barrel, the inner core barrel can also be equipped with a fiberglass inner barrel with the advantages of light weight, high temperature resistance, corrosion resistance, high strength, and smooth tube wall. The resistance of the core entering the barrel is small when using the fiberglass inner barrel. The full-core fiberglass inner barrel can also be cut into several sections and sealed at both ends for easy storage. The combined length of the downhole can also be selected according to the downhole conditions. The internal structure can realize internal washing. After the drill string reaches the bottom, the pump is started to circulate and wash the bottom hole and the inner barrel, and then a ball is thrown to take the core. The core catcher adopts the form of a main and auxiliary cutter, which is a triangular hard alloy cutter bar, solving the problem in the prior art that two centralizing blocks with flat tops at the top can only play a centralizing role and cannot stop rotation, and the cutter is easy to cut out spiral curves or left and right swing lines on the core surface and cannot cut out a straight line.

[0040] Three spring cutters are installed in the pressure sleeve of the present invention. The spring cutters protrude from the inner wall of the pressure sleeve, and when the core enters the pressure sleeve, directional marks are made on the core surface. Thus, from the measuring instrument receiving tube to the cutter on the pressure sleeve is on the same generatrix, realizing a connection form with only longitudinal displacement and no change in torsional orientation. The spring cutter includes a cutter and a spring piece. The cutter is welded to one end of the spring piece, and a rivet hole is opened at the other end of the spring piece. The spring cutter is connected to the pressure sleeve by a rivet. The spring piece and the cutter form a cantilever beam structure. The device for making directional marks adopts a telescopic spring cutter. The normal stress applied by the spring piece to the cutter is much greater than the compressive hardness of the rock. And when the core diameter changes due to the hardness of the rock and the newness of the drill bit, the spring piece can play a role in automatically adjusting the position of the cutter and the magnitude of the normal stress applied to the rock. Therefore, clear directional marking scratches can be obtained under different lithological conditions.

[0041] A first thrust bearing and a second thrust bearing are installed on the suspension shaft of the present invention. The bearing box, the cushion block, the suspension shaft, the first thrust bearing, and the second thrust bearing are combined together through their own geometric shapes. This structure is beneficial to reducing and minimizing the rotation of the inner core barrel during core taking and increasing the stability of the core entering the barrel.

[0042] In the present invention, an upper roller centralizing bearing is installed between the water separating joint and the upper outer barrel centralizer, and a lower roller centralizing bearing is installed between the core catcher and the core bit. The upper roller centralizing bearing and the lower roller centralizing bearing cooperate to centralize the upper and lower parts of the core inner barrel, which is beneficial to reducing and minimizing the rotation of the core inner barrel and increasing the stability of the core entering the barrel. Description of the Drawings

[0043] Figure 1 It is a schematic structural diagram of a directional coring tool of this patent.

[0044] Figure 2 It is a schematic structural diagram of the first technical solution of the suspension assembly.

[0045] Figure 3 It is a schematic structural diagram of the first technical solution of the directional cutter.

[0046] Figure 4 It is a schematic structural diagram of a directional coring tool of this patent after the ball is thrown.

[0047] Figure 5 It is a schematic structural diagram of the spring cutter.

[0048] Figure 6 It is a schematic structural diagram of the second technical solution of the directional cutter.

[0049] Figure 7 It is a schematic structural diagram of the second technical solution of the suspension assembly.

[0050] Figure 8 It is a schematic structural diagram of the second technical solution of a directional coring tool of this patent.

[0051] In the figure: 1. positioning joint, 2. pressure-bearing seat, 3. ball sleeve, 4. first steel ball, 5. suspension joint, 6. suspension assembly, 6-1. bearing box, 6-2. suspension shaft, 6-3. second steel ball, 6-4. bearing ring, 6-5. bearing support, 6-6. water separating joint, 6-7. ball seat, 7. upper outer barrel centralizer, 8. outer core barrel, 9. inner core barrel, 10. lower outer barrel centralizer, 11. pressure sleeve, 12. adjusting ring, 13. core catcher, 13-1. left centralizing cutter, 13-2. right centralizing cutter, 13-3. main cutter, 14. core bit, 15. electronic multi-point measuring instrument, 16. spring cutter, 16-1. cutter teeth, 16-2. spring plate, 17. rivet, 18-1. spacer, 18-3. first thrust bearing, 18-4. second thrust bearing, 19-1. upper roller centralizing bearing, 19-2. lower roller centralizing bearing. Detailed Embodiments

[0052] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, 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 unnecessarily confusing the concepts of the present invention.

[0053] Embodiment 1:

[0054] Referring to Figure 1 、 Figure 2 and Figure 3 , a directional coring tool includes a positioning sub 1, a pressure-bearing seat 2, a ball sleeve 3, a first steel ball 4, a suspension sub 5, a suspension assembly 6, an upper outer barrel centralizer 7, an outer core barrel 8, an inner core barrel 9, a lower outer barrel centralizer 10, a pressure sleeve 11, an adjusting ring 12, a core catcher 13, and a coring bit 14.

[0055] The positioning sub, the upper outer barrel centralizer, the lower outer barrel centralizer, and the coring bit are sequentially threadedly connected.

[0056] The suspension assembly 6 includes a bearing box 6-1, a suspension shaft 6-2, a second steel ball 6-3, a bearing ring 6-4, a bearing support 6-5, a water distribution joint 6-6, and a ball seat 6-7. The suspension sub 5 is threadedly connected to the bearing box 6-1, and the bearing box 6-1 is threadedly connected to the bearing support 6-5. The suspension shaft 6-2 is threadedly connected to the water distribution joint 6-6, and the water distribution joint 6-6 is threadedly connected to the ball seat 6-7. The bearing box 6-1, the bearing ring 6-4, the bearing support 6-5, the second steel ball 6-3, and the suspension shaft 6-2 fit together by their own geometric shapes and are pressed tightly by gravity during tool use.

[0057] The positioning sub 1 is threadedly connected to the upper outer barrel centralizer 7, the upper outer barrel centralizer 7 is threadedly connected to the outer core barrel 8, the outer core barrel 8 is threadedly connected to the lower outer barrel centralizer 9, and the lower outer barrel centralizer 10 is threadedly connected to the coring bit 14. The suspension sub 5 is threadedly connected to the suspension assembly 6, the suspension assembly 6 is threadedly connected to the inner core barrel 9, the inner core barrel 9 is threadedly connected to the pressure sleeve 11, and the pressure sleeve 11 is threadedly connected to the core catcher 13. The adjusting ring 12 is located between the pressure sleeve 11 and the core catcher 13, and its axial movement is restricted by the extrusion between the pressure sleeve 11 and the core catcher 13. The pressure-bearing seat 2 is connected to the positioning sub 1 by a pin. The ball sleeve 3 is threadedly connected to the positioning sub 1. The first steel ball 4 is located inside the ball sleeve 3. The two radial through holes of the positioning sub 1 and the suspension sub 5 are opposite to each other and are connected by the first steel ball 4. The electronic multi-point inclinometer 15 is installed in the non-magnetic drill collar at the upper end of the coring tool and is integrally connected to the suspension shaft 6-2 at the upper end of the inner core barrel 9 so that there is no relative displacement.

[0058] Three directional chisels are welded at the lower end of the core claw 13, and the directional chisels include a left aligning chisel 13-1, a right aligning chisel 13-2, and a main chisel 13-3.

[0059] Embodiment 2:

[0060] Reference Figure 4 Before drilling, the valve steel balls 6-8 are not installed. After drilling to the bottom of the well, the pump is turned on to circulate the mud. At this time, the mud enters the inner core barrel 9 through the inner holes of the positioning joint 1, the pressure seat 2, the suspension joint 5 and the suspension assembly 6, and then returns to the annular space from the inner core barrel 9. In this way, the bottom of the well can be cleaned and the inner core barrel 9 can be flushed. After the mud is treated and the bottom of the well is cleaned, the valve steel balls 6-8 are put in, and the valve steel balls 6-8 fall into the ball seat 6-7, blocking the mud passage of the inner core barrel 9, and coring drilling begins.

[0061] When coring, the chisel on the core claw 13 continuously carves on the core before it changes its original state, leaving a marking groove, and the electronic multi-point measuring instrument 15 is used to measure the azimuth, well inclination and well inclination azimuth of the main cutter 13-3 mark while drilling. The left straightening chisel 13-1 and the right straightening chisel 13-2 play the role of stopping and straightening, so as to prevent the main chisel 13-3 from easily carving a spiral curve or a left-right swing line on the core surface, and failing to carve a straight line.

[0062] After the coring drilling is completed, the drill tool is slid and pressurized. The weight of the drill tool is transmitted to the pressurizing device through the valve steel balls 6-8, and the pressurizing device transmits the pressure to the pressure-bearing seat 2. The pressure-bearing seat 2 transmits the pressure to the pin. When the pressure on the pin exceeds the shear strength, the pin is sheared off, the pressure-bearing seat 2 falls, the radial through hole of the pressure-bearing seat 2 is opposite to the radial through hole of the suspension joint 5, the first steel ball 4 rolls out from the ball sleeve 3, and falls into the cavity formed by the suspension assembly 6 and the valve steel balls 6-8 through the radial through hole of the pressure-bearing seat 2. The suspension assembly 6, the pressure-bearing seat 2, and the inner core barrel 9 are smashed down, forcing the core claw 13 to shrink along the conical surface of the inner cavity of the coring drill bit 14, cutting and wrapping the core, and achieving the purpose of coring.

[0063] Embodiment three:

[0064] Reference Figure 5 and Figure 6Another technical solution for the directional chisel in this patent is to install three spring chisels 16 in the pressing sleeve 11. The spring chisels 16 protrude from the inner wall of the pressing sleeve 11, and make directional marks on the surface of the core when the core enters the pressing sleeve 11. As a result, the spring chisels 16 from the measuring instrument housing tube to the pressing sleeve 11 are on the same busbar, realizing a connection form with only longitudinal displacement but no torsional azimuth change. The spring chisel 16 includes a tooth 16-1 and a spring sheet 16-2. The tooth 16-1 is welded to one end of the spring sheet 16-2, and a rivet hole is opened at the other end of the spring sheet 16-2. The spring chisel 16 is connected to the pressing sleeve 11 by rivets. The spring sheet 16-2 and the cutter teeth 16-1 form a cantilever beam structure, and the retractable spring cutter 16 is used as the directional marking device. The spring sheet 16-2 applies a positive stress on the cutter teeth 16-1 that is much greater than the rock's resistance to indentation hardness. When the core diameter changes due to the hardness of the rock and the age of the drill bit, the spring sheet 16-2 can automatically adjust the position of the cutter teeth 16-1 and apply a positive stress to the rock. Therefore, clear directional marking marks can be obtained under different rock conditions.

[0065] Embodiment five:

[0066] Reference Figure 7 The second technical solution for the suspension assembly of this patent is to install the first thrust bearing 18-3 and the second thrust bearing 18-4 on the suspension shaft 6-2. The bearing box 6-1, the cushion block 18-1, the suspension shaft 6-2, the first thrust bearing 18-3, and the second thrust bearing 18-4 are combined together through their own geometric shapes. This structure is conducive to reducing and reducing the rotation of the coring inner barrel and increasing the stability of the core feeding barrel.

[0067] Embodiment six:

[0068] Reference Figure 8 The second technical solution of the directional coring tool of this patent is to keep the components and connection methods of the first technical solution unchanged, install the upper roller straightening bearing 19-1 between the water diversion joint 6-6 and the upper outer tube straightening device 7, install the lower roller straightening bearing 19-2 between the core claw 13 and the coring drill bit 14, and the upper roller straightening bearing 19-1 cooperates with the lower roller straightening bearing 19-2 to straighten the inner core tube 9 up and down. It is beneficial to reduce and reduce the rotation of the coring inner tube and increase the stability of the core feeding tube.

[0069] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A directional coring tool, comprising a tool body composed of a positioning joint (1), an upper outer barrel centralizer (7), an outer core barrel (8), a lower outer barrel centralizer (10), and a coring bit (14) that are sequentially threadedly connected; a pressure-bearing seat (2), a suspension joint (5), a suspension assembly (6), an inner core barrel (9), a pressure sleeve (11), and a core catcher (13) are sequentially installed in the tool body from top to bottom; the pressure-bearing seat (2) is sleeved in the positioning joint (1) through shear pins; characterized in that, The upper end of the suspension joint (5) is sleeved between the lower ends of the positioning joint (1) and the pressure-bearing seat (2). The positioning joint (1), the upper end of the suspension joint (5), and the lower end of the pressure-bearing seat (2) are in clearance fit. Radial through-holes are provided in the positioning joint (1), the upper end of the suspension joint (5), and the lower end of the pressure-bearing seat (2). The diameter of the radial through-hole is larger than the diameter of the first steel ball (4). The ball sleeve (3) is threadedly connected to the outer end of the radial through-hole of the positioning joint (1). The radial through-holes of the positioning joint (1) and the upper end of the suspension joint (5) are in corresponding positions. The radial through-hole at the lower end of the pressure-bearing seat (2) is higher than the radial through-hole at the upper end of the suspension joint (5). The first steel ball (4) is located between the radial through-holes of the positioning joint (1) and the upper end of the suspension joint (5) to axially fix the positioning joint (1) and the suspension joint (5). The suspension assembly (6) is rotatably sleeved on the lower end of the suspension joint (5) through a bearing assembly. The lower end of the positioning joint (1) is threadedly connected to the upper end of the upper outer barrel centralizer (7). The lower end of the upper outer barrel centralizer (7) is threadedly connected to the upper end of the outer core barrel (8). The lower end of the outer core barrel (8) is threadedly connected to the upper end of the lower outer barrel centralizer (10). The lower end of the lower outer barrel centralizer (10) is threadedly connected to the upper end of the core bit (14). The lower end of the water distribution joint (6-6) is threadedly connected to the inner core barrel (9) through an external thread. The lower end of the inner core barrel (9) is threadedly connected to the upper end of the pressure sleeve (11). The lower end of the pressure sleeve (11) is threadedly connected to the upper end of the core catcher (13). A limiting step is provided between the lower end of the pressure sleeve (11) and the upper end of the core catcher (13). The adjusting ring (12) is located between the limiting steps, and the axial movement is restricted by the extrusion between the pressure sleeve (11) and the core catcher (13). The suspension assembly (6) includes a bearing assembly, a suspension shaft (6-2), a water distribution joint (6-6), and a ball seat (6-7). The bearing assembly includes a bearing box (6-1), a first thrust bearing (18-3), and a bearing support (6-5). The lower end of the suspension joint (5) is threadedly connected to the upper end of the bearing box (6-1). The inner thread at the lower end of the bearing box (6-1) is threadedly connected to the outer thread at the upper end of the bearing support (6-5). The lower end of the suspension shaft (6-2) has an external thread that is threadedly connected to the inner thread at the upper end of the water distribution joint (6-6). The lower end of the water distribution joint (6-6) has an inner thread that is threadedly connected to the outer thread at the upper end of the ball seat (6-7). The suspension shaft (6-2) is rotatably sleeved in the bearing box (6-1) through a bearing assembly. Limiting steps are provided on the inner wall of the lower end of the bearing box (6-1) and the outer wall of the suspension shaft (6-2). The limiting steps respectively form two opposite annular grooves with the upper end faces of the bearing support (6-5) and the water distribution joint (6-6). The first thrust bearing (18-3) is sleeved in the annular groove. An upper roller centralizing bearing (19-1) and a lower roller centralizing bearing (19-2) are also included. A limiting step is provided on the outer part of the upper end of the upper outer barrel centralizer (7) to form an annular groove with the lower end face of the water distribution joint (6-6). A limiting step is provided on the outer part of the core bit (14) to form an annular groove with the outer wall of the core catcher (13).The upper roller centralizing bearing (19-1) and the lower roller centralizing bearing (19-2) are respectively installed in the annular groove; the upper end of the pressure-bearing seat (2) is provided with a limiting step whose outer diameter is larger than the inner diameter of the suspension joint (5). When the shear pin is cut off and the pressure-bearing seat (2) drops, the limiting step at the upper end of the pressure-bearing seat (2) is hooked on the upper end of the suspension joint (5), and the radial through holes on the pressure-bearing seat (2) and the radial through holes on the suspension joint (5) are opposite to each other.

2. The directional coring tool according to claim 1, characterized in that The bearing assembly also includes a second thrust bearing (18-4), the outer wall of the suspension shaft (6-2) has two limiting steps, one of which separates the annular groove of the outer wall of the suspension shaft (6-2) into two upper and lower parts, and the second thrust bearing (18-4) is installed in the lower annular groove.

3. A directional coring tool according to claim 2, characterized in that, A core orientation cutter is welded on the inner wall of the lower end of the core claw (13).

4. The directional coring tool according to claim 3, wherein, The core orientation chisel comprises a left centering chisel (13-1), a right centering chisel (13-2), and a main chisel (13-3) which are arranged unequally in the circumferential direction.

5. The directional coring tool according to claim 4, characterized in that, The core orientation carving knife is a three-edged hard alloy knife blade.

6. The directional coring tool according to claim 5, wherein, When coring, the shear pin is sheared off, the pressure seat (2) falls, the radial through hole of the pressure seat (2) is opposite to the radial through hole of the suspension joint (5), the first steel ball (4) rolls out from the ball sleeve (3), the suspension assembly (6), the pressure seat (2), and the inner core barrel (9) are smashed down, forcing the core claw (13) to shrink along the conical surface of the inner cavity of the coring drill bit (14), cut off and wrap the core, and achieve the purpose of coring.

7. A directional coring tool according to any one of claims 1-6, characterized in that Three spring cutters (16) are installed in the pressing sleeve (11). The spring cutters (16) protrude from the inner wall of the pressing sleeve (11). The spring cutters (16) comprise cutter teeth (16-1) and a spring sheet (16-2). The cutter teeth (16-1) are welded to one end of the spring sheet (16-2), and a rivet hole is formed at the other end of the spring sheet (16-2). The spring cutters (16) are connected to the pressing sleeve (11) by rivets.

8. A directional coring tool according to claim 7, characterized in that, The cutting teeth (16-1) are made of cemented carbide.

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