A core drilling tool and core extraction method for ball-throwing controlled core extraction

Abstract

A ball-drop controlled core extraction tool and method are disclosed, relating to the field of core recovery. The ball-drop controlled core extraction tool includes an outer tube assembly consisting of a drill pipe joint, an outer tube, and a drill bit connection; and an inner tube assembly consisting of a ball-drop diverter, a torsion actuator, an inner core tube, and a core extractor connection. The core extractor includes an inner shaft sleeve connected to the inner core tube, an outer shaft sleeve, and multiple rotatable cutting blades. The ball-drop diverter selectively delivers mud simultaneously to the mud channel and torsion actuator between the outer tube assembly and the inner tube assembly, or pressurizes the mud and delivers it separately to the torsion actuator. The torsion actuator drives the outer shaft sleeve to rotate relative to the inner shaft sleeve during pressurized mud delivery, thereby driving the cutting blades to rotate synchronously and cut the core. The ball-drop controlled core extraction tool and method allow operators to easily use mechanical transmission to control the rotation of the cutting blades at the surface to cut and support the core.

Description

Technical Field

[0001] This application relates to the field of core recovery, and more specifically, to a core drilling tool and a core extraction method for controlling core fragmentation by dropping balls. Background Technology

[0002] Rock cores are important physical geological data for studying and understanding underground geology and mineral resources, and they need to be obtained using specialized core drilling tools.

[0003] Patent CN113738298B discloses a pressure-holding coring device, comprising an outer tube assembly, an inner tube assembly, an anti-torsion component, a sealing gate, and a controller. The outer tube assembly includes an outer cylinder and a drill bit; the outer cylinder is vertically oriented and has a first receiving cavity and a first opening. The inner tube assembly includes an inner cylinder, a cutting component, and a lifting component; the inner cylinder has a second receiving cavity and a second opening. The anti-torsion component counteracts the torsional force transmitted to the inner cylinder by the rotation of the outer cylinder and buffers the vibration transmitted from the outer cylinder to the inner cylinder. The sealing gate opens during the core entry into the second receiving cavity; it automatically closes after the cutting component cuts the core and the lifting component lifts the inner cylinder and the cut core upwards, thus sealing the second receiving cavity. It also discloses the use of a telescopic structure to drive an elastic steel sheet to rotate and cut the core.

[0004] However, it uses a controller to electrically control the telescopic structure to drive the elastic steel sheet to rotate and cut the rock core, which may lead to the failure of the electric control and makes it difficult to meet the needs of stable core sampling in complex underground environments. Summary of the Invention

[0005] The purpose of this application is to provide a core drilling tool and a core extraction method for ball-throwing control, which enables operators to use mechanical transmission to control the rotation of the cutting blade to cut and support the core at the ground surface.

[0006] This application is implemented as follows:

[0007] This application provides a core drilling tool for ball-drop controlled core extraction, which includes an outer tube assembly and an inner tube assembly disposed within the outer tube assembly. A mud channel is formed between the outer tube assembly and the inner tube assembly. The outer tube assembly includes a drill pipe joint, an outer tube, and a drill bit connected in sequence. The inner tube assembly includes a ball-drop diverter, a torsion actuator, an inner core tube, and a core extractor connected in sequence.

[0008] The core extractor includes an inner sleeve connected to the inner core tube, an outer sleeve rotatably fitted onto the inner sleeve, and multiple cutting mechanisms. The inner and outer sleeves are respectively provided with a first receiving hole and a second receiving hole corresponding to each cutting mechanism. Each cutting mechanism includes a cutting blade rotatably connected to the first and second receiving holes. When the outer sleeve rotates relative to the inner sleeve, it pushes each cutting blade to rotate synchronously and extend into the inner sleeve to cut and support the core or to accommodate it in the corresponding first and second receiving holes.

[0009] The ball-drop diverter is used to selectively deliver mud to both the mud channel and the torsion drive simultaneously, or to pressurize the mud and deliver it separately to the torsion drive. The torsion drive is used to receive the mud delivered by the ball-drop diverter and deliver it to the mud channel. When delivering pressurized mud, it drives the outer bushing to rotate relative to the inner bushing, pushing each cutting blade to rotate synchronously and extend into the inner bushing to cut and support the core.

[0010] In some alternative implementations, the ball-dropping diverter includes an upper diverter cylinder, a lower diverter cylinder, and a flow-limiting ball. The upper diverter cylinder is used to receive mud delivered by the drill pipe joint. The upper and lower diverter cylinders are coaxially connected. The lower diverter cylinder has a blind hole at one end facing the upper diverter cylinder. The upper diverter cylinder has an upper connecting channel connecting the drill pipe joint and the blind hole. The inner wall of the blind hole near the upper diverter cylinder has multiple diversion channels. The diversion channels connect to the lower diverter cylinder at the end away from the upper diverter cylinder. The blind hole at the end away from the upper diverter cylinder has multiple bypass holes connecting the mud channels. The flow-limiting ball is configured to move through the drill pipe joint and the upper connecting channel into the blind hole to isolate the mud channels and bypass holes, so that the mud flowing through the diversion channels and bypass holes is pressurized and flows through the diversion channels alone.

[0011] In some optional implementations, a single-action mechanism is connected between the drill pipe joint and the ball-dropping diverter. The single-action mechanism includes an upper cylinder, a lower cylinder, a hollow rotating shaft with both ends rotatably passing through the upper and lower cylinders respectively, and an annular bearing support. One end of the upper cylinder is connected to the drill pipe joint. The inner walls of adjacent ends of the upper and lower cylinders are respectively connected to the outer walls of both ends of the bearing support by threads. The inner walls of both ends of the bearing support are respectively connected to bearings sleeved at both ends of the hollow rotating shaft. The hollow rotating shaft has a rotating shaft inner hole that passes through both ends of it. The hollow rotating shaft is connected to the upper diverter.

[0012] In some optional embodiments, the torsion actuator includes an actuator cylinder connected to the lower diversion cylinder, a stator fixedly disposed within the actuator cylinder, a rotor rotatably disposed within the actuator cylinder, and a clamping shaft coaxially connected to the rotor. The stator has multiple sector teeth, and the rotor has sector blades corresponding one-to-one with the sector teeth. The sector teeth and sector blades are arranged alternately along the circumference of the actuator cylinder. The actuator cylinder, stator, sector teeth, rotor, and sector blades enclose and form multiple high-pressure chambers and multiple low-pressure chambers arranged alternately along the circumference of the actuator cylinder. The actuator cylinder has at least one high-pressure damping hole connecting the high-pressure chamber and the mud channel, and at least one low-pressure damping hole connecting the low-pressure chamber and the mud channel. The rotor has mud holes that connect the diversion channel and each high-pressure chamber. The actuator cylinder is connected to the outer shaft sleeve through the middle layer tube, and the clamping shaft is connected to the inner shaft sleeve through the core inner tube.

[0013] In some alternative implementations, the drive cylinder has multiple fan-shaped grooves arranged circumferentially, and the retaining shaft is threadedly connected to a limiting screw corresponding to each fan-shaped groove. One end of the limiting screw extends into the corresponding fan-shaped groove. When the rotor rotates relative to the stator, the fan-shaped groove blocks the corresponding limiting screw to limit the rotation angle of the rotor.

[0014] In some alternative embodiments, the inner core tube includes a core receiving tube and a core tube end cap connected to one end of the core receiving tube. The retaining shaft has a retaining hole extending through both ends thereto. The core tube end cap is engaged with the retaining hole. The core tube end cap has an end cap channel connecting the core receiving tube and the mud hole. The core tube end cap has a one-way overflow valve inside for limiting the one-way flow of mud from the core receiving tube into the end cap channel.

[0015] In some alternative implementations, when the core tube end cap is snapped into the snap-fit ​​hole, the limiting screw moves axially to press against or stop pressing against the outer wall of the core tube end cap.

[0016] In some alternative implementations, each cutting mechanism includes a first pin and a second pin, with one end of the cutting blade sleeved on the corresponding first pin and the second pin through a pin hole and an arc-shaped hole, respectively. The two ends of the first pin and the two ends of the second pin are respectively connected to the two sides of the corresponding first receiving hole and the two sides of the corresponding second receiving hole.

[0017] This application also provides a method for controlling core fragmentation by throwing a ball, which includes the following steps:

[0018] The core drilling tool for controlling core fragmentation using the above-mentioned ball dropping method is drilled into the target formation, so that the core is inserted into the core inner tube through the inner shaft sleeve;

[0019] The ball-feeding distributor pressurizes the mud and delivers it separately to the torsion drive, so that when the torsion drive receives the pressurized mud delivered by the ball-feeding distributor, it drives the outer shaft sleeve to rotate relative to the inner shaft sleeve.

[0020] When the outer sleeve rotates relative to the inner sleeve, it drives each cutting blade to rotate synchronously and extend into the inner sleeve to cut and support the rock core.

[0021] In some alternative implementations, the flow-limiting ball is inserted into the ball-dropping distributor via the drill pipe joint, blocking the connection between the ball-dropping distributor and the mud channel, so that the mud entering the ball-dropping distributor is pressurized and delivered separately to the torsional drive.

[0022] The beneficial effects of this application are as follows: The core drilling tool for ball-drop controlled core extraction provided by this application includes an outer tube assembly and an inner tube assembly disposed within the outer tube assembly, forming a mud channel between the outer tube assembly and the inner tube assembly. The outer tube assembly includes a drill pipe joint, an outer tube, and a drill bit connected in sequence. The inner tube assembly includes a ball-drop diverter, a torsion actuator, an inner core tube, and a core extractor connected in sequence. The core extractor includes an inner shaft sleeve connected to the inner core tube, an outer shaft sleeve rotatably fitted on the inner shaft sleeve, and multiple cutting mechanisms. The inner shaft sleeve and the outer shaft sleeve are respectively provided with a first receiving hole and a second receiving hole corresponding one-to-one with the cutting mechanisms. Each cutting mechanism has... The system includes cutting blades rotatably connected to a first and a second receiving hole; when the outer sleeve rotates relative to the inner sleeve, it drives each cutting blade to rotate synchronously and extend into the inner sleeve to cut and support the core, or to house it in the corresponding first and second receiving holes; a ball-dropping diverter is used to selectively deliver mud to both the mud channel and the torsion actuator simultaneously, or to pressurize the mud and deliver it separately to the torsion actuator; the torsion actuator receives the mud delivered by the ball-dropping diverter and delivers it to the mud channel, and drives the outer sleeve to rotate relative to the inner sleeve while delivering pressurized mud, thereby driving each cutting blade to rotate synchronously and extend into the inner sleeve to cut and support the core. The ball-dropping controlled core cutting drill bit and core cutting method provided in this application can facilitate operators to control the cutting blade rotation using a mechanical transmission method at the surface to cut and support the core. It has the advantages of reliable core cutting, controllable core cutting action, simple operation, high reliability, high core recovery rate, and good sample fidelity, avoiding the problems of uncertain downhole conditions caused by existing core cutting methods. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a cross-sectional structural schematic diagram of the core drilling tool for ball-drop controlled core extraction provided in an embodiment of this application;

[0025] Figure 2 This is a partial cross-sectional view of the connection between the drill pipe joint and the single-action mechanism in the core drilling tool for ball-drop controlled core extraction provided in this embodiment of the application.

[0026] Figure 3 This is a partial cross-sectional view of the single-action mechanism, ball-dropping distributor, torsion actuator, and core inner tube connection in the core drilling tool for ball-dropping controlled core extraction provided in this embodiment of the application.

[0027] Figure 4 For along Figure 3 Sectional view of section line AA in the middle;

[0028] Figure 5 For along Figure 3 Sectional view of the BB section line;

[0029] Figure 6 A partial cross-sectional view of the connection between the single-action mechanism, ball-dropping distributor, torsion actuator, and core inner tube in the core drilling tool for ball-dropping control core extraction provided in this application embodiment;

[0030] Figure 7 An exploded structural diagram of the core extractor in the core drilling tool for ball-drop controlled core extraction provided in this embodiment of the application;

[0031] Figure 8 A cross-sectional view of the core extractor in the core drilling tool for ball-drop controlled core extraction provided in this application embodiment.

[0032] Figure 9 For along Figure 8 A schematic diagram of the cross-sectional structure of the core extractor in the first use state of the CC profile.

[0033] Figure 10 For along Figure 8 A schematic diagram of the cross-sectional structure of the core extractor in the second operational state at the CC profile.

[0034] In the diagram: 100, outer tube assembly; 110, mud channel; 120, drill pipe joint; 130, outer tube; 140, drill bit; 200, inner tube assembly; 210, intermediate tube; 300, single-action mechanism; 310, upper shell; 320, lower shell; 330, hollow rotating shaft; 331, inner hole of rotating shaft; 340, bearing support seat; 341, bearing; 350, locking nut; 360, upper sealing ring; 370, lower... Sealing ring; 380, Lubrication chamber; 390, Oil nozzle; 400, Ball distributor; 410, Upper distributor cylinder; 420, Lower distributor cylinder; 430, Flow-limiting ball; 440, Blind hole; 450, Upper connecting channel; 460, Flow-dividing channel; 461, Flow-dividing hole; 462, Connecting hole; 470, Bypass hole; 480, Flow-limiting valve chamber; 500, Torsional actuator; 510, Actuator cylinder; 511, High-pressure damping hole; 5 12. Low-pressure damping orifice; 513. Fan-shaped groove; 520. Stator; 521. Fan-shaped tooth; 522. Connecting screw; 530. Rotor; 531. Fan-shaped blade; 532. Mud hole; 533. Mud connection port; 540. Shaft retainer; 541. Limiting screw; 542. Snap-fit ​​hole; 550. High-pressure chamber; 560. Low-pressure chamber; 600. Core inner tube; 610. Core receiving tube; 620. Core tube end cap; 6 30. End cap channel; 640. One-way overflow valve; 700. Core extractor; 710. Inner shaft sleeve; 711. First receiving hole; 720. Outer shaft sleeve; 721. Second receiving hole; 730. Cutting mechanism; 731. Cutting blade; 732. First pin; 733. Second pin; 740. End sampling tube; 750. Pin hole; 760. Arc-shaped hole; 770. First pin hole; 780. Second pin hole. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0038] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0040] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0041] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] The features and performance of the core drilling tool for ball-drop controlled core extraction of this application are further described in detail below with reference to embodiments.

[0043] like Figure 1 , Figure 2, Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown in the figure, this application provides a core drilling tool for ball-drop controlled core extraction, which includes an outer tube assembly 100 and an inner tube assembly 200 disposed within the outer tube assembly 100; a mud channel 110 is formed between the outer tube assembly 100 and the inner tube assembly 200; the outer tube assembly 100 includes a drill pipe joint 120, an outer tube 130 and a drill bit 140 connected in sequence; the inner tube assembly 200 includes a single-action mechanism 300, a ball-drop diverter 400, a torsion actuator 500, a core inner tube 600 and a core extractor 700 connected in sequence;

[0044] Among them, such as Figure 2 As shown, the single-action mechanism 300 includes an upper cylinder 310, a lower cylinder 320, a hollow rotating shaft 330 with both ends rotatably passing through the upper cylinder 310 and the lower cylinder 320 respectively, and an annular bearing support seat 340. One end of the upper cylinder 310 is threaded to the outer wall of the drill pipe joint 120. The inner walls of adjacent ends of the upper cylinder 310 and the lower cylinder 320 are threaded to the outer walls of both ends of the bearing support seat 340 respectively. Bearings 341 sleeved on both ends of the hollow rotating shaft 330 are respectively connected to the inner walls of both ends of the bearing support seat 340. A locking device for limiting its axial position is sleeved on the hollow rotating shaft 330. Nut 350, hollow rotating shaft 330 is fitted with upper sealing ring 360 and lower sealing ring 370 respectively on the outer walls of both ends, which are sealed to the inner walls of upper cylinder 310 and lower cylinder 320. The inner walls of upper cylinder 310, lower cylinder 320, hollow rotating shaft 330 and bearing support seat 340 form a lubrication cavity 380. The bearing support seat 340 is provided with an oil injection nozzle 390 for injecting lubricating oil into the lubrication cavity 380. Hollow rotating shaft 330 has a rotating shaft inner hole 331 that passes through both ends. One end of the rotating shaft inner hole 331 is connected to the drill pipe joint 120 for conveying mud.

[0045] like Figure 3 and Figure 6As shown, the ball-throwing diverter 400 includes an upper diverting cylinder 410, a lower diverting cylinder 420, and a flow-limiting ball-throwing device 430. One end of the upper diverting cylinder 410 is threaded to the end of the hollow rotating shaft 330 away from the drill pipe joint 120, and the other end is threaded to the lower diverting cylinder 420. The lower diverting cylinder 420 has a blind hole 440 at the end facing the upper diverting cylinder 410. The upper diverting cylinder 410 has an upper connecting channel 450 that connects the inner hole 331 of the rotating shaft and the blind hole 440. The inner wall of the blind hole 440 near the upper diverting cylinder 410 has four diverting channels 460. The diverting channels 460 connect to the end of the lower diverting cylinder 420 away from the upper diverting cylinder 410. Each diverting channel 460 includes a diverting hole 461 extending radially along the lower diverting cylinder 420 and a diverting channel 460 extending radially along the lower diverting cylinder 420. The axially extending connecting hole 462 of the diverter cylinder 420 and the blind hole 440 at one end away from the upper diverter cylinder 410 are provided with four bypass holes 470 connecting the mud channels 110. The connection between the bypass holes 470 and the blind holes 440 forms a flow-limiting valve chamber 480. The ball-dropping diverter 400 is used to selectively transport the mud conveyed by the inner hole 331 of the rotating shaft to the mud channel 110 and the torsion drive 500 or pressurize and transport it to the torsion drive 500. The flow-limiting ball 430 is configured to move through the drill pipe joint 120, the inner hole 331 of the rotating shaft, the upper connecting channel 450 and the blind hole 440 to the flow-limiting valve chamber 480 to block the bypass holes 470, so that the normal pressure mud that has passed through the diverter channel 460 and the bypass holes 470 is pressurized and then passes through the diverter channel 460.

[0046] like Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, the torsion actuator 500 includes an actuator cylinder 510 with one end threadedly connected to the lower distributor cylinder 420, a stator 520 fixedly connected to the actuator cylinder 510 by connecting screws 522, a rotor 530 rotatably disposed within the actuator cylinder 510, and a retaining shaft 540 coaxially connected to the rotor 530 by threads. The stator 520 has two sector teeth 521, and the rotor 530 has two sector blades 531 corresponding to the sector teeth 521. The two sector teeth 521 and the two sector blades 531 are arranged alternately around the circumference of the actuator cylinder 510. The actuator cylinder 510, stator 521, sector teeth 521, rotor 530, and sector blades 531 enclose and form two high-pressure chambers 550 and two [other chambers] arranged alternately around the circumference of the actuator cylinder 510. The low-pressure chamber 560 and the actuator cylinder 510 are provided with a high-pressure damping hole 511 connecting the high-pressure chamber 550 and the mud channel 110, and a low-pressure damping hole 512 connecting the low-pressure chamber 560 and the mud channel 110. The rotor 530 is provided with a mud hole 532 connecting the diversion channel 460. The mud hole 532 passes through both ends of the rotor 530, and the inner wall of the mud hole 532 is connected to each high-pressure chamber 550 through a mud connecting port 533. The actuator cylinder 510 has three fan-shaped waist grooves 513 arranged circumferentially. The retaining shaft 540 is threadedly connected to three limiting screws 541, one end of which extends into the fan-shaped waist grooves 513. When the rotor 530 rotates relative to the stator 520, the fan-shaped waist grooves 513 block the rotation of the limiting screws 541 to limit the rotation angle of the rotor 530. The end of the actuator cylinder 510 away from the lower diversion cylinder 420 is threadedly connected to the middle layer tube 210.

[0047] like Figure 3 and Figure 6 As shown, the core inner tube 600 includes a core receiving tube 610 and a core tube end cap 620 connected to one end of the core receiving tube 610 by a thread. The retaining shaft 540 is provided with retaining holes 542 passing through both ends of it. The core tube end cap 620 is retained in the retaining holes 542. The core tube end cap 620 is provided with an end cap channel 630 connecting the core receiving tube 610 and the mud hole 532. The core tube end cap 620 is provided with a one-way overflow valve 640 for limiting the one-way flow of mud from the core receiving tube 610 into the end cap channel 630. When the core tube end cap 620 is retained in the retaining holes 542, the limiting screw 541 moves axially to press or stop pressing against the outer wall of the core tube end cap 620 to limit or stop limiting the position of the core tube end cap 620.

[0048] like Figure 7 , Figure 8 , Figure 9 and Figure 10As shown, the core extractor 700 includes an inner shaft sleeve 710, an outer shaft sleeve 720 rotatably sleeved on the outside of the inner shaft sleeve 710, four cutting mechanisms 730, and an end sampling cylinder 740 sleeved on the end of the inner shaft sleeve 710; the other end of the core receiving tube 610 is connected to the inner shaft sleeve 710, and the end of the middle tube away from the driver cylinder 510 is threadedly connected to the outer shaft sleeve 720; wherein, the outer wall of the inner shaft sleeve 710 has four first receiving holes 711 penetrating its inner wall, each first receiving hole 711 extending along the circumference of the inner shaft sleeve 710, and the four first receiving holes 711 along the inner shaft sleeve 710... The outer sleeve 720 has four second receiving holes 721 extending through its inner wall on its outer wall. Each second receiving hole 721 extends circumferentially along the outer sleeve 720. The four second receiving holes 721 are arranged circumferentially along the outer sleeve 720. The first receiving holes 711 and the second receiving holes 721 correspond one-to-one. Each first receiving hole 711 and the corresponding second receiving hole 721 are arranged sequentially along the radial direction of the inner sleeve 710. Each cutting mechanism 730 includes an arc-shaped cutting blade 731, a first pin 732, and a second pin 733. One end of the cutting blade 731 is respectively connected to... The through-hole 750 and the arc-shaped hole 760 are sleeved on the corresponding first pin 732 and second pin 733. The two ends of the first pin 732 and the two ends of the second pin 733 are respectively connected to the two sides of a first receiving hole 711 and the two sides of a corresponding second receiving hole 721. The outer wall of one end of the inner shaft sleeve 710 has a first pin hole 770 that passes through the two sides of the four first receiving holes 711. The first pins 732 of the four cutting mechanisms 730 pass through the four first pin holes 770 and the arc-shaped holes 760 on the four cutting blades 731 respectively. The outer wall of one end of the outer shaft sleeve 720 has a through-hole 760 that passes through the four first pin holes 711 and the arc-shaped hole 760 on the four cutting blades 731 respectively. The second pin holes 780 on both sides of the receiving hole 721, and the second pins 733 of the four cutting mechanisms 730 pass through the four second pin holes 780 and the pin holes 750 on the four cutting blades 731 respectively; the end sampling tube 740 is sleeved on the outer wall of the end of the inner shaft sleeve 710 with the first pin hole 770 and the end abuts against the end of the outer shaft sleeve 720 with the second pin hole 780; when the outer shaft sleeve 720 rotates relative to the inner shaft sleeve 710, it pushes the four cutting blades 731 to rotate synchronously and extend into the inner shaft sleeve 710 to cut and support the rock core or to be received in the corresponding first receiving hole 711 and second receiving hole 721.

[0049] The core extraction tool provided in this application embodiment can actively control the downhole core extraction action by dropping a flow-limiting ball 430 into the drill bit after drilling to the target formation and taking samples. It can also drop a flow-limiting ball 430 of appropriate size according to the actual core shear force requirements of the formation to ensure that the core is sheared and sealed and lifted in the core inner tube 600, making core extraction more reliable and the core extraction action more controllable. It avoids the uncertainty of downhole working conditions caused by existing tackling methods and has the effects of simple operation, high reliability, high core recovery rate and good sample fidelity.

[0050] The core extraction method using the ball-drop controlled core extraction drill bit provided in this application embodiment includes the following steps: The ball-drop controlled core extraction drill bit is installed at the bottom of the drill pipe and drills towards the target formation. During drilling, surface mud is pumped through the drill pipe joint 120 and passes through the inner hole 331 of the hollow rotating shaft 330 of the single-action mechanism 300, and is delivered to the ball-drop diverter 400. The mud then enters the upper connecting channel 450 of the upper diverter cylinder 410 through the inner hole 331 of the rotating shaft and into the blind hole 440 of the lower diverter cylinder 420. The mud then enters the torsion actuator 500 and the mud channel 110 through the diversion channel 460 and the bypass hole 470, respectively. Since the flow-limiting ball-dropping 430 is not used to block and isolate the blind hole 440 and the bypass hole 470, the blind hole 440 and the bypass hole 470... With complete penetration, the mud has a large flow area and a small pressure increase, so the mud with lower pressure is delivered to the lower distribution cylinder 420 near the torsion actuator 500 through the diversion hole 461 and connecting hole 462 of the diversion channel 460. At this time, the low-pressure mud through the diversion channel 460 enters each high-pressure chamber 550 through the mud hole 532 and mud connecting port 533 on the rotor 530 of the torsion actuator 500, and then flows into the mud channel 110 through the high-pressure damping hole 511. At this time, each low-pressure chamber 560 of the torsion actuator 500 and the mud channel 110 are connected through the low-pressure damping hole 512, so that the pressure of the high-pressure chamber 550 and the low-pressure chamber 560 are the same. The rotor 530 and the stator 520 remain relatively stationary and do not produce relative movement. The torsion actuator 500 will not drive the core extractor 700 to work.

[0051] When drilling reaches the target formation, and the target core passes through the inner shaft sleeve 710 and enters the core receiving tube 610 of the core inner tube 600, it is necessary to cut the core. The flow-limiting ball 430 is inserted into the drill pipe and moves through the drill pipe joint 120, the inner hole 331 of the rotating shaft, the upper connecting channel 450, and the blind hole 440 to the flow-limiting valve chamber 480 to block the bypass hole 470. The flow-limiting valve chamber 480, which is connected to the blind hole 440 and the bypass hole 470, is isolated. The surface mud, after being pumped through the drill pipe joint 120, the hollow rotating shaft 330 of the single-action mechanism 300, the upper connecting channel 450 of the upper diversion cylinder 410, and the blind hole 440 of the lower diversion cylinder 420, can only flow into the torsion actuator 500 through the diversion channel 460, greatly reducing the mud flow area. This increases the mud pressure, and as the mud pressure increases, it enters each high-pressure chamber 550 through the mud hole 532 and mud connection port 533 on the rotor 530 of the torsion actuator 500 via the diversion channel 460, and then flows into the mud channel 110 through the high-pressure damping hole 511. At this time, the pressure connecting each low-pressure chamber 560 of the torsion actuator 500 and the mud channel 110 is less than the pressure inside each high-pressure chamber 550. When the pressure in the high-pressure chamber 550 is greater than the pressure in the low-pressure chamber 560, the rotor 530 rotates relative to the stator 520. This causes the core receiving tube 610 and the inner shaft sleeve 710 of the core inner tube 600 to rotate relative to the middle layer tube 210 and the outer shaft sleeve 720 connected to the actuator cylinder 510.

[0052] When the outer sleeve 720 rotates relative to the inner sleeve 710, one end of each of the four second receiving holes 721 on the outer sleeve 720 pushes one end of each of the four cutting blades 731 fitted onto the first pin 732 and the second pin 733 to rotate, causing the four cutting blades 731 to rotate clockwise around the first pin 732 until they extend into the inner sleeve 710 to cut and support the core. When the core extractor 700 is pulled out of the ground with the drill rod, and the outer sleeve 720 is rotated counterclockwise relative to the inner sleeve 710 to reset, one end of each of the four second receiving holes 721 on the outer sleeve 720 moves in the opposite direction, pushing one end of each of the four cutting blades 731 fitted onto the first pin 732 and the second pin 733 to rotate, causing the four cutting blades 731 to rotate in the opposite direction around the first pin 732 until they retract into the first receiving hole 711 and the second receiving hole 721 to stop supporting the core and expose the core for easy removal to complete the core extraction operation.

[0053] The single-action mechanism 300 is supported by a hollow rotating shaft 330 that rotatably passes through the upper cylinder 310 and lower cylinder 320 via a bearing 341 connected to the inner walls of the upper cylinder 310, lower cylinder 320, and bearing support seat 340. The hollow rotating shaft 330 has a rotating shaft inner hole 331 extending through both ends, allowing it to communicate with the drill pipe joint 120 for stable mud delivery to the ball-feeding distributor 400. The outer walls at both ends of the hollow rotating shaft 330 are respectively fitted with… An upper sealing ring 360 and a lower sealing ring 370 are provided to seal against the inner walls of the upper cylinder 310 and the lower cylinder 320, respectively. The inner walls of the upper cylinder 310, the lower cylinder 320, the outer wall of the hollow rotating shaft 330, and the inner wall of the bearing support 340 enclose a lubrication cavity 380. The bearing support 340 is provided with an oil injection nozzle 390 for injecting lubricating oil into the lubrication cavity 380, which enables the bearing 341 to be in the sealed lubrication cavity 380, which is beneficial to the lubrication of the bearing 341 and extends the service life of the bearing 341.

[0054] The driver cylinder 510 has three fan-shaped grooves 513 arranged circumferentially. The retaining shaft 540 is threadedly connected to three limiting screws 541, one end of which extends into the fan-shaped grooves 513. When the rotor 530 rotates relative to the stator 520, the fan-shaped grooves 513 block the rotation of the limiting screws 541 to limit the rotation angle of the rotor 530. Thus, the fan-shaped grooves 513 of the driver cylinder 510 limit the rotation angle of the limiting screws 541 of the retaining shaft 540 connected to the rotor 530, thereby limiting the rotation angle of the rotor 530 relative to the stator 520 to drive the outer shaft sleeve 720 to rotate relative to the inner shaft sleeve 710 by a preset angle. This ensures that the cutting blade 731 rotates by a preset angle to extend into the inner shaft sleeve 710 to cut the rock core or retract into the first receiving hole 711 and the second receiving hole 721.

[0055] The inner core tube 600 includes a core receiving tube 610 and a core tube end cap 620 that is threaded to one end of the core receiving tube 610. The retaining shaft 540 is provided with retaining holes 542 that pass through both ends of it. The core tube end cap 620 is engaged in the retaining holes 542. The inner core tube 600 transmits torque through the retaining holes 542 of the retaining shaft 540 and the core tube end cap 620. This enables the rotor 530 to drive the retaining shaft 540 to rotate, which in turn drives the core tube end cap 620 and the core receiving tube 610 to rotate, thereby driving the inner shaft sleeve 710 to rotate.

[0056] The core tube end cap 620 is provided with an end cap channel 630 connecting the core receiving tube 610 and the mud hole 532. The core tube end cap 620 is provided with a one-way overflow valve 640 to limit the unidirectional flow of mud from the core receiving tube 610 into the end cap channel 630. This allows the mud carried by the core to be discharged through the one-way overflow valve 640 into the end cap channel 630 when the core enters the core receiving tube 610, and further allows the mud to pass through the end cap channel 630 and the snap-fit ​​hole 54. 2. After entering the mud hole 532, it is discharged into the mud channel 110; when the core tube end cap 620 is engaged in the engagement hole 542, the limiting screw 541 moves axially to press or stop pressing the outer wall of the core tube end cap 620 to limit or stop the position of the core tube end cap 620. The limiting screw 541 connected to the retaining shaft 540 can be used to radially press the outer wall of the core tube end cap 620, thereby ensuring a stable connection between the core tube end cap 620 and the retaining shaft 540.

[0057] In this embodiment, the flow-limiting ball 430 does not need to be spherical; it can be any shape. It only needs to be able to move through the inside of the drill pipe joint 120, the inner hole of the rotating shaft 331, the upper connecting channel 450, and the blind hole 440 to the flow-limiting valve cavity 480 to block the bypass hole 470 and isolate the bypass hole 470 and the blind hole 440.

[0058] In this embodiment, the isolation of the bypass hole 470 and the blind hole 440 does not need to be completely isolated. Such isolation can be either complete or partial. When partially isolated, it is only necessary to reduce the flow rate of mud flowing into the mud channel 110 through the bypass hole 470 in the blind hole 440 and increase the mud pressure entering the torsion drive 500 through the diversion channel 460 to drive the rotor 530 to rotate a preset angle relative to the stator 520.

[0059] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A core drilling tool for controlled core extraction using ball dropping, comprising an outer tube assembly and an inner tube assembly disposed within the outer tube assembly, wherein a mud channel is formed between the outer tube assembly and the inner tube assembly, and the outer tube assembly comprises a drill pipe joint, an outer tube, and a drill bit connected in sequence, characterized in that, The inner tube assembly includes a ball-feeding diverter, a torsion actuator, a core inner tube, and a core extractor connected in sequence. The core extractor includes an inner sleeve connected to the inner core tube, an outer sleeve rotatably fitted onto the inner sleeve, and multiple cutting mechanisms. The inner sleeve and the outer sleeve are respectively provided with a first receiving hole and a second receiving hole corresponding to each of the cutting mechanisms. Each cutting mechanism includes a cutting blade rotatably connected to the first receiving hole and the second receiving hole. When the outer sleeve rotates relative to the inner sleeve, it pushes each cutting blade to rotate synchronously and extend into the inner sleeve to cut and support the core or to accommodate it in the corresponding first receiving hole and the second receiving hole. The ball-drop diverter is used to selectively deliver mud to the mud channel and the torsion drive simultaneously, or to pressurize the mud and deliver it separately to the torsion drive; the torsion drive is used to receive the mud delivered by the ball-drop diverter and deliver it to the mud channel, and when delivering pressurized mud, it drives the outer shaft sleeve to rotate relative to the inner shaft sleeve, pushing each of the cutting blades to rotate synchronously and extend into the inner shaft sleeve to cut and support the core.

2. The core drilling tool for controlled core extraction according to claim 1, characterized in that, The ball-dropping diverter includes an upper diverter cylinder, a lower diverter cylinder, and a flow-limiting ball. The upper diverter cylinder receives the mud delivered by the drill pipe joint. The upper and lower diverter cylinders are coaxially connected. The lower diverter cylinder has a blind hole at one end facing the upper diverter cylinder. The upper diverter cylinder has an upper connecting channel connecting the drill pipe joint and the blind hole. The inner wall of the blind hole near the upper diverter cylinder has multiple diversion channels. The diversion channels connect to the lower diverter cylinder at the end away from the upper diverter cylinder. The blind hole at the end away from the upper diverter cylinder has multiple bypass holes connecting the mud channel. The flow-limiting ball is configured to move through the drill pipe joint and the upper connecting channel into the blind hole to isolate the mud channel and the bypass holes, so that the mud flowing through the diversion channels and bypass holes is pressurized and flows through the diversion channels alone.

3. The core drilling tool for controlled core extraction according to claim 2, characterized in that, A single-action mechanism is connected between the drill pipe joint and the ball-throwing diverter. The single-action mechanism includes an upper cylinder, a lower cylinder, a hollow rotating shaft with both ends rotatably passing through the upper cylinder and the lower cylinder, and an annular bearing support. One end of the upper cylinder is connected to the drill pipe joint. The inner walls of adjacent ends of the upper cylinder and the lower cylinder are respectively connected to the outer walls of both ends of the bearing support by threads. The inner walls of both ends of the bearing support are respectively connected to bearings sleeved at both ends of the hollow rotating shaft. The hollow rotating shaft has a rotating shaft inner hole that passes through both ends of it. The hollow rotating shaft is connected to the upper diverter cylinder.

4. The core drilling tool for controlled core fragmentation according to claim 2, characterized in that, The torsional actuator includes an actuator cylinder connected to the lower diversion cylinder, a stator fixedly disposed within the actuator cylinder, a rotor rotatably disposed within the actuator cylinder, and a retaining shaft coaxially connected to the rotor. The stator has multiple sector teeth, and the rotor has sector blades corresponding one-to-one with the sector teeth. The sector teeth and sector blades are arranged alternately along the circumference of the actuator cylinder. The actuator cylinder, the stator, the sector teeth, the rotor, and the sector blades enclose and form multiple high-pressure chambers and multiple low-pressure chambers arranged alternately along the circumference of the actuator cylinder. The actuator cylinder has at least one high-pressure damping hole connecting the high-pressure chamber and the mud channel, and at least one low-pressure damping hole connecting the low-pressure chamber and the mud channel. The rotor has a mud hole that connects the diversion channel and each of the high-pressure chambers. The actuator cylinder is connected to the outer shaft sleeve through a middle layer tube, and the retaining shaft is connected to the inner shaft sleeve through the core inner tube.

5. The core drilling tool for controlled core fragmentation according to claim 4, characterized in that, The drive cylinder has multiple fan-shaped grooves arranged at intervals along its circumference. The retaining shaft is threadedly connected to a limiting screw that corresponds to each of the fan-shaped grooves. One end of the limiting screw extends into the corresponding fan-shaped groove. When the rotor rotates relative to the stator, the fan-shaped groove blocks the corresponding limiting screw to limit the rotation angle of the rotor.

6. The core drilling tool for controlled core fragmentation according to claim 5, characterized in that, The core inner tube includes a core receiving tube and a core tube end cap connected to one end of the core receiving tube. The retaining shaft has retaining holes extending through both ends. The core tube end cap is retained in the retaining holes. The core tube end cap has an end cap channel connecting the core receiving tube and the mud hole. The core tube end cap has a one-way overflow valve inside to limit the mud from flowing unidirectionally from the core receiving tube into the end cap channel.

7. The core drilling tool for controlled core fragmentation according to claim 6, characterized in that, When the core tube end cap is engaged in the engagement hole, the limiting screw moves axially to press against or stop pressing against the outer wall of the core tube end cap.

8. The core drilling tool for controlled core fragmentation according to claim 6, characterized in that, Each of the cutting mechanisms includes a first pin and a second pin. One end of the cutting blade is sleeved on the corresponding first pin and the corresponding second pin through a pin hole and an arc-shaped hole, respectively. The two ends of the first pin and the two ends of the second pin are respectively connected to the two sides of the corresponding first receiving hole and the two sides of the corresponding second receiving hole.

9. A method for controlling core fragmentation by throwing a ball, characterized in that, It includes the following steps: The core drilling tool for core fragmentation control as described in any one of claims 1 to 8 is drilled into the target formation, so that the core enters the core inner tube through the inner shaft sleeve; The ball-feeding diverter pressurizes the mud and delivers it separately to the torsion drive, so that when the torsion drive receives the pressurized mud delivered by the ball-feeding diverter, it drives the outer shaft sleeve to rotate relative to the inner shaft sleeve. When the outer sleeve rotates relative to the inner sleeve, it drives each of the cutting blades to rotate synchronously and extend into the inner sleeve to cut and support the rock core.

10. The method for controlling core extraction by ball dropping according to claim 9, characterized in that, The flow-limiting ball is inserted into the ball-dropping distributor through the drill pipe joint, blocking the connection between the ball-dropping distributor and the mud channel, so that the mud entering the ball-dropping distributor is pressurized and delivered separately to the torsion drive.

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