Anti-jamming coring tool

Abstract

The present application relates to the technical field of coring tools, and discloses a clogging-preventing coring tool which comprises an upper joint of an outer tube, an upper outer tube centralizer, a lower outer tube centralizer and a coring bit which are sequentially connected together from top to bottom through threads, a plug is connected to the upper joint of the outer tube through internal threads, a central rod is rotatably installed in the upper joint of the outer tube at a lower side position of the plug, the lower end of the central rod is located in the upper outer tube centralizer, a drilling fluid channel is arranged in the upper joint of the outer tube and extends through the upper joint of the outer tube from top to bottom, an inner tube joint is connected to the outer side of the lower end of the central rod through threads, and a positioning ring is installed on the outer side of the central rod at an upper side position of the inner tube joint. The present application has a reasonable and compact structure and is convenient to use. The present application can lift the inner lining tube when the core is clogged, so that the core in the lining tube is lifted, the core below can continue to enter the outer lining tube, the problem of core clogging is solved, and the core recovery rate is improved.

Description

Technical Field

[0001] This invention relates to the field of core extraction tools, specifically a core extraction tool designed to prevent core blockage. Background Technology

[0002] To accurately assess ultra-deep oil and gas resources, core sampling is essential. Analysis of the retrieved cores allows for the determination of data such as oil and water saturation, porosity, and crude oil properties, which are used to calculate geological reserves, formulate and adjust oilfield development plans, and improve oil recovery. However, with increasing well depth, ultra-deep oil and gas reservoirs become densely cemented, subject to high temperatures and pressures, resulting in highly complex geological conditions. This places higher demands on core sampling tools and technologies, making core sampling increasingly difficult. Furthermore, ultra-deep dolomite formations are extremely hard and have poor drillability, leading to low mechanical drilling rates, numerous interbedded layers, easily broken cores, and a high risk of core blockage. Encountering fractured formations exacerbates core blockage, reducing the core recovery rate, decreasing single-trip footage, lowering core recovery efficiency, and increasing drilling costs.

[0003] A core sampling tool is a tool used in geological exploration and oil drilling. Its working principle is mainly based on obtaining underground rock samples during drilling. Key components of a current core sampling tool include inner and outer core barrels, a core gripping mechanism, and a shunt suspension device. At the end of core sampling, the core gripper grasps the core and pulls it out using the top core bit, capturing the core sample. The inner core barrel holds the core, while the outer barrel provides protection and support. During drilling, the drill bit first grinds the core by rotating, and once the core is finely ground, the drill string is lifted to break it off.

[0004] During the coring process, loosely cemented sandstone or conglomerate can easily clog the core claws or the core cylinder after entering the drill bit cavity or the core cylinder. This can prevent the lower core from entering the inner cylinder, leading to core blockage and ultimately resulting in low core recovery rate and core efficiency. These two indicators are key indicators for coring.

[0005] The existing tools have the following shortcomings: First, they are not easy to unblock after being plugged, and the reliability of the tools is not high; second, they lack vibration reduction function, resulting in low tool stability, which directly affects the core recovery rate; third, the tool life and reliability are not high when coring operations are performed on different well types (directional wells and horizontal wells); and fourth, the existing coring tools cannot meet the coring operation requirements under the high temperature and high pressure conditions of ultra-deep wells at depths of 10,000 meters. Summary of the Invention

[0006] This invention provides a coring tool that prevents coring blockage, overcoming the shortcomings of the prior art. It can effectively solve the problem that existing coring tools are difficult to unblock after coring, resulting in low coring yield and efficiency.

[0007] The technical solution of this invention is achieved through the following measures: a core-retrieving tool for preventing core blockage, comprising an outer cylinder upper connector, an upper outer cylinder centralizing sub, a lower outer cylinder centralizing sub, and a core drill bit, which are threaded together from top to bottom. A plug is threaded into the upper outer cylinder connector. A center rod is rotatably installed inside the upper outer cylinder connector at the lower side of the plug. The lower end of the center rod is located inside the upper outer cylinder centralizing sub. A drilling fluid channel runs vertically through the upper outer cylinder connector. An inner cylinder connector is threaded to the outer side of the lower end of the center rod. The upper side of the inner cylinder connector... A positioning ring is installed on the outside of the center rod. The lower side of the inner cylinder joint is threaded to the upper inner cylinder. The lower side of the upper inner cylinder is threaded to the inner cylinder straightening short section. The lower side of the inner cylinder straightening short section is threaded to the lower inner cylinder. A core claw is installed on the lower side of the lower inner cylinder through a core claw sleeve. A liner is provided on the lower inner side of the upper inner cylinder. The lower end of the liner is located below the core claw. The liner is a multi-stage liner with at least two layers of inner and outer sleeves. A drive mechanism is installed on the center rod that can pull the innermost liner upward. The lower end of the inner liner can be hooked to the upper end of the outer liner.

[0008] The following are further optimizations and / or improvements to the above-mentioned technical solution: Preferably, the drive structure includes a battery, a motor, a drum, and a wire rope. The battery, motor, and drum are installed on the upper part of the central rod. A retaining ring is installed on the central rod above the battery by a countersunk screw. The motor is connected to the battery and the motor is connected to the drum for transmission. A wire rope is wound around the outside of the drum. A lifting ring is provided on the upper side of the innermost liner. The end of the wire rope is connected to the lifting ring.

[0009] Preferably, it also includes a pressure sensor. A pressure sensor is provided on the inner side of the upper part of the plug. The pressure sensor is connected to the motor through a cable. When the pressure sensor reaches the specified pressure, it energizes the motor to operate. The upper part of the plug has a through hole that connects the inside and outside. The through hole is connected to the installation position of the pressure sensor.

[0010] Preferably, a tapered roller bearing is installed between the inner side of the outer cylinder upper joint and the outer side of the upper end of the center rod, and a deep groove ball bearing is installed between the outer cylinder upper joint and the upper part of the center rod at the position corresponding to the lower position of the tapered roller bearing.

[0011] Preferably, an outer ring platform is provided on the outer side of the upper part of the central rod, and a spring is fitted on the central rod between the lower side of the outer ring platform and the inner side of the upper joint of the outer cylinder.

[0012] Preferably, the innermost liner has an exhaust hole that runs vertically through it, a ball seat is installed on the inner side of the lower end of the center rod, the ball seat has a sealing ball that can block the through hole in the middle of the ball seat, and at least one diversion hole that runs vertically through it is evenly distributed along the circumference of the lower part of the center rod.

[0013] Preferably, the core claw sleeve includes an upper core claw sleeve and a lower core claw sleeve. The core claw includes an upper core claw and a lower core claw. The upper core claw sleeve is threadedly connected to the lower inner cylinder. The upper core claw is installed on the lower inner side of the upper core claw sleeve. The lower core claw sleeve is threadedly connected to the lower outer side of the upper core claw sleeve. The lower core claw is installed on the inner side of the lower core claw sleeve. The upper core claw and the lower core claw have different tapers and different elasticities. An inner cylinder centering ring is provided between the lower outer side of the lower core claw sleeve and the inner side of the core drill bit.

[0014] Preferably, at least three sets of sealing rings are provided between the plug and the upper connector of the outer cylinder, and a gasket is installed between the inner side of the lower end of the upper connector of the outer cylinder and the center rod through a countersunk pin.

[0015] Preferably, the lower end of the plug has a cavity on its inner side, and the cavity is filled with sealing grease.

[0016] Preferably, the liner is made of a material resistant to high temperature and high pressure.

[0017] The present invention has a reasonable and compact structure and is easy to use. By setting up a multi-layered liner, it can lift the inner liner when core blockage occurs, thereby lifting the rock core inside the liner. The rock core below can continue to enter the outer liner, thus solving the problem of core blockage and improving the core recovery rate. Attached Figure Description

[0018] Appendix Figure 1 This is a schematic diagram of the front cross-sectional structure according to an embodiment of the present invention.

[0019] Appendix Figure 2 This is a cross-sectional structural diagram of the present invention in use.

[0020] The codes in the attached diagram are as follows: 1 is the outer cylinder upper connector, 2 is the plug, 3 is the sealing ring, 4 is the tapered roller bearing, 5 is the countersunk screw, 6 is the deep groove ball bearing, 7 is the spring, 8 is the countersunk pin, 9 is the motor, 10 is the inner cylinder connector, 11 is the ball seat, 12 is the upper outer cylinder straightening section, 13 is the pressure sensor, 14 is the through hole, 15 is the retaining ring, 16 is the battery, 17 is the washer ring, 18 is the center rod, 19 is the positioning ring, 20 is the sealing ball, 21 is the upper inner cylinder, 22 is the liner lifting ring, 23 is the liner, 24 is the inner cylinder straightening section, 25 is the lower outer cylinder straightening section, 26 is the lower inner cylinder, 27 is the upper core claw sleeve, 28 is the upper core claw, 29 is the lower core claw sleeve, 30 is the lower core claw, 31 is the inner cylinder straightening ring, 32 is the core drill bit, and 33 is the diversion hole. Detailed Implementation

[0021] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0022] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0023] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figure 1 , 2 As shown, the anti-clogging core-taking tool includes an outer cylinder upper connector 1, an upper outer cylinder centralizing sub 12, a lower outer cylinder centralizing sub 25, and a core-taking drill bit 32, which are threaded together from top to bottom. A plug 2 is internally threaded onto the outer cylinder upper connector 1. A center rod 18 is rotatably installed inside the outer cylinder upper connector 1 at the lower side of the plug 2. The lower end of the center rod 18 is located inside the upper outer cylinder centralizing sub 12. The outer cylinder upper connector 1 has a vertically penetrating drilling fluid channel. An inner cylinder connector 10 is threaded to the outer side of the lower end of the center rod 18. A positioning ring 1 is installed on the outer side of the center rod 18 at the upper side of the inner cylinder connector 10. 9. The lower side of the inner cylinder joint 10 is threaded to the upper inner cylinder 21. The lower side of the upper inner cylinder 21 is threaded to the inner cylinder straightening short section 24. The lower side of the inner cylinder straightening short section 24 is threaded to the lower inner cylinder 26. The lower side of the lower inner cylinder 26 is equipped with a core claw through a core claw sleeve. The lower inner side of the upper inner cylinder 21 is provided with a liner 23. The lower end of the liner 23 is located below the core claw. The liner 23 is a multi-stage liner 23 with at least two layers of inner and outer sleeves. The central rod 18 is equipped with a drive mechanism that can pull the innermost liner 23 upward. The lower end of the inner liner 23 can be hooked with the upper end of the outer liner 23.

[0024] The positioning ring 19 is also connected to the center rod 18 via a positioning pin. In use, taking the two-stage liner 23 as an example, the upper outer tube connector 1, the upper outer tube straightening short section 12, the lower outer tube straightening short section 25, and the core drill bit 32 rotate together. During drilling, the core first enters the innermost liner 23 of the multi-stage liner 23 from the drill bit cavity. If the drilling rig speed is significantly reduced or slowed down on the ground, it indicates core blockage. The drive mechanism is then controlled to pull the innermost liner 23 upward, and the core inside the innermost liner 23 is lifted up together. The lower part of the outer liner 23 then has space to accommodate the core again, and the lower core can continue to enter the liner 23. When the innermost liner 23 is lifted to the upper end of the outer liner 23, it will pull the outer liner 23 upward. Then the lower core is located outside the liner 23 and contacts the core claw. The core claw holds the core tightly, and the liner 23 is lifted up further to break off the core, completing the core extraction, improving the core recovery rate, and improving the efficiency of on-site core extraction. In this invention, the core claw remains outside the liner 23 until the liner 23 is fully lifted out of the drill bit cavity. Therefore, the core entry is not obstructed by the core claw, and no mud adhering to the core will stick to it, preventing slippage. This avoids mud buildup on the inner side of the core, preventing slippage and ensuring stable core gripping and operational feasibility. The multi-stage liner 23 effectively solves the technical problem of core blockage in fractured formations, and by placing the core claw outside the liner 23 for stable operation, it improves the core recovery rate.

[0025] The above-mentioned anti-blocking core extraction tools can be further optimized and / or improved according to actual needs: Example 2: As shown in the attached document Figure 1 , 2 As shown, the drive structure includes a battery 16, a motor 9, a drum, and a wire rope. The battery 16, motor 9, and drum are mounted on the upper part of the central rod 18. A retaining ring 15 is mounted on the central rod 18 above the battery 16 via countersunk screws 5. The motor 9 is connected to the battery 16 and is also connected to the drum for transmission. A wire rope is wound around the outside of the drum. A lifting ring is located on the upper side of the innermost liner 23, and the end of the wire rope is connected to the lifting ring. When the core is blocked, the motor 9 is controlled to rotate, pulling the drum and the wire rope, thereby pulling the innermost liner 23 upwards, lifting the blocked core, and resolving the blockage problem.

[0026] Example 3: As shown in the attached document Figure 1 , 2As shown, it also includes a pressure sensor 13. The pressure sensor 13 is installed on the inner side of the upper part of the plug 2. The pressure sensor 13 is connected to the motor 9 via a cable. When the pressure sensor 13 reaches the specified pressure, it energizes the motor 9 to operate. The upper end of the plug 2 has a through hole 14 that connects the inner and outer sides, and the through hole 14 is connected to the installation position of the pressure sensor 13. Conventional control of the motor 9 requires the installation of cables, etc. In ultra-deep wells, cables are costly, easily damaged, and signal transmission is affected. Using the pressure sensor 13 eliminates the need for long cables. When the core is blocked, the drilling fluid pressure is increased, and the drilling fluid enters the installation position of the pressure sensor 13 through the through hole 14. When the pressure sensor 13 detects that the pressure has reached the threshold, it energizes the motor 9, thereby pulling the innermost liner 23 upward through the wire rope to unblock it.

[0027] Example 4: As shown in the appendix Figure 1 , 2 As shown, a tapered roller bearing 4 is installed between the inner side of the outer cylinder upper joint 1 and the outer side of the upper end of the center rod 18. A deep groove ball bearing 6 is installed between the outer cylinder upper joint 1 and the upper part of the center rod 18, corresponding to the position below the tapered roller bearing 4. By using both tapered roller bearing 4 and deep groove ball bearing 6, the tool can be supported under multi-directional forces in horizontal and directional wells, enabling the tool to rotate flexibly in different postures, while ensuring safety and reliability, and improving the tool's service life.

[0028] Example 5: As shown in the attached document Figure 1 , 2 As shown, an outer ring platform is provided on the upper outer side of the center rod 18, and a spring 7 is fitted on the center rod 18 between the lower side of the outer ring platform and the inner side of the upper connector 1 of the outer cylinder. By setting the spring 7, the stability of the drill bit is improved, the axial impact load is effectively absorbed, and the risk of core blockage is reduced.

[0029] Example 6: As attached Figure 1 , 2 As shown, the innermost liner 23 has a through-hole on its upper side. A ball seat 11 is installed on the inner side of the lower end of the center rod 18. The ball seat 11 has a sealing ball 20 that can block the through hole in the middle of the ball seat 11. At least one diversion hole 33 with internal and external penetrations is evenly distributed along the circumference of the lower part of the center rod 18. When the core enters the liner 23 and the innermost liner 23 is lifted, the air in the lower inner cylinder 26 and the upper inner cylinder 21 is squeezed upward. When the gas passes through the ball seat 11, it pushes open the sealing ball 20 and exhausts the gas through the diversion hole 33, thus avoiding the problem of pressure buildup inside the cylinder causing difficulty in core entry and lifting of the liner 23.

[0030] Example 7: As attached Figure 1 , 2As shown, the core claw sleeve includes an upper core claw 28 set 27 and a lower core claw 30 set 29. The core claws themselves include an upper core claw 28 and a lower core claw 30. The upper core claw 28 set 27 is threadedly connected to the lower inner cylinder 26. An upper core claw 28 is installed on the lower inner side of the upper core claw 28 set 27, and a lower core claw 30 set 29 is threadedly connected to the lower outer side of the upper core claw 28 set 27. A lower core claw 30 is installed on the inner side of the lower core claw 30 set 29. The upper core claw 28 and lower core claw 30 have different tapers and elasticity. An inner cylinder centering ring 31 is provided between the lower outer side of the lower core claw 30 set 29 and the inner side of the core drill bit 32. The different tapers and elasticity of the upper core claw 28 and lower core claw 30 allow them to be used in scenarios with varying core hardness, thus broadening their applicability.

[0031] Example 8: As attached Figure 1 , 2 As shown, at least three sets of sealing rings 3 are provided between the plug 2 and the upper connector 1 of the outer cylinder, and a gasket 17 is installed between the inner side of the lower end of the upper connector 1 of the outer cylinder and the center rod 18 through a countersunk pin 8. This arrangement provides better sealing and prevents drilling fluid from entering the drive mechanism.

[0032] Example 9: As attached Figure 1 , 2 As shown, the lower end of plug 2 has a cavity on its inner side, which is filled with sealing grease. The bearing is sealed by using the sealing grease.

[0033] Example 10: As attached Figure 1 , 2 As shown, the liner 23 is made of a high-temperature and high-pressure resistant material. The use of a high-temperature resistant material can meet the high-temperature and high-pressure environment inside ultra-deep wells.

[0034] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A heart extraction tool for preventing heart blockage, characterized in that... The system comprises, from top to bottom, a threaded connection of an outer cylinder upper connector, an upper outer cylinder centralizing sub, a lower outer cylinder centralizing sub, and a core drill bit. A plug is threaded into the upper outer cylinder connector. A center rod is rotatably mounted inside the upper outer cylinder connector, located below the plug. The lower end of the center rod is located inside the upper outer cylinder centralizing sub. The upper outer cylinder connector has a vertically penetrating drilling fluid channel. An inner cylinder connector is threaded to the outer side of the lower end of the center rod. A positioning ring is installed on the outer side of the center rod above the inner cylinder connector. The inner cylinder... The lower side of the connector is threaded to an upper inner cylinder, the lower side of the upper inner cylinder is threaded to an inner cylinder straightening short section, the lower side of the inner cylinder straightening short section is threaded to a lower inner cylinder, a core claw is installed on the lower side of the lower inner cylinder through a core claw sleeve, a liner is provided on the lower inner side of the upper inner cylinder, the lower end of the liner is located below the core claw, the liner is a multi-stage liner with at least two layers of inner and outer sleeves, a drive mechanism is installed on the central rod that can pull the innermost liner upward, the lower end of the inner liner can be hooked to the upper end of its outer liner.

2. The anti-blocking core extraction tool according to claim 1, characterized in that... The drive structure includes a battery, a motor, a drum, and a wire rope. The battery, motor, and drum are mounted on the upper part of the central rod. A retaining ring is mounted on the central rod above the battery using countersunk screws. The motor is connected to the battery and the motor is connected to the drum via a drive connection. A wire rope is wound around the outside of the drum. A lifting ring is provided on the upper side of the innermost liner, and the end of the wire rope is connected to the lifting ring.

3. The anti-blocking core extraction tool according to claim 2, characterized in that... It also includes a pressure sensor. The pressure sensor is located on the inner side of the upper part of the plug. The pressure sensor is connected to the motor via a cable. When the pressure sensor reaches the specified pressure, it powers on the motor to operate. The upper part of the plug has a through hole that connects the inside and outside of the plug. The through hole is connected to the installation position of the pressure sensor.

4. The anti-blocking core extraction tool according to claim 1, 2, or 3, characterized in that... A tapered roller bearing is installed between the inner side of the outer cylinder upper joint and the outer side of the upper end of the center rod. A deep groove ball bearing is installed between the outer cylinder upper joint and the upper part of the center rod at the position below the tapered roller bearing; or / and, an outer ring platform is provided on the outer side of the upper part of the center rod, and a spring is fitted on the center rod between the lower side of the outer ring platform and the inner side of the outer cylinder upper joint.

5. The anti-blocking core extraction tool according to claim 1, 2, or 3, characterized in that... The innermost liner has an exhaust hole that runs vertically through it. A ball seat is installed on the inner side of the lower end of the center rod. The ball seat has a sealing ball that can block the through hole in the middle of the ball seat. At least one diversion hole that runs vertically through it is evenly distributed along the circumference of the lower part of the center rod.

6. The anti-blocking core extraction tool according to claim 3, characterized in that... The innermost liner has an exhaust hole that runs vertically through it. A ball seat is installed on the inner side of the lower end of the center rod. A sealing ball that can block the through hole in the middle of the ball seat is installed on the ball seat. At least one diversion hole that runs vertically through it is evenly distributed along the circumference of the lower part of the center rod.

7. The anti-blocking core extraction tool according to claim 1, 2, 3, or 6, characterized in that... The core claw sleeve includes an upper core claw sleeve and a lower core claw sleeve. The core claw includes an upper core claw and a lower core claw. The upper core claw sleeve is threadedly connected to the lower inner cylinder. The upper core claw is installed on the lower inner side of the upper core claw sleeve, and the lower core claw sleeve is threadedly connected to the lower outer side of the upper core claw sleeve. The lower core claw is installed on the inner side of the lower core claw sleeve. The upper core claw and the lower core claw have different tapers and different elasticity. An inner cylinder centering ring is provided between the lower outer side of the lower core claw sleeve and the inner side of the core drill bit.

8. The anti-blocking core extraction tool according to claim 4, characterized in that... The core claw sleeve includes an upper core claw sleeve and a lower core claw sleeve. The core claw includes an upper core claw and a lower core claw. The upper core claw sleeve is threadedly connected to the lower inner cylinder. The upper core claw is installed on the lower inner side of the upper core claw sleeve, and the lower core claw sleeve is threadedly connected to the lower outer side of the upper core claw sleeve. The lower core claw is installed on the inner side of the lower core claw sleeve. The upper core claw and the lower core claw have different tapers and different elasticity. An inner cylinder centering ring is provided between the lower outer side of the lower core claw sleeve and the inner side of the core drill bit.

9. The anti-blocking core extraction tool according to claim 5, characterized in that... The core claw sleeve includes an upper core claw sleeve and a lower core claw sleeve. The core claw includes an upper core claw and a lower core claw. The upper core claw sleeve is threadedly connected to the lower inner cylinder. The upper core claw is installed on the lower inner side of the upper core claw sleeve, and the lower core claw sleeve is threadedly connected to the lower outer side of the upper core claw sleeve. The lower core claw is installed on the inner side of the lower core claw sleeve. The upper core claw and the lower core claw have different tapers and different elasticity.

10. The anti-blocking core extraction tool according to claim 1 or 2, characterized in that... At least three sets of sealing rings are provided between the plug and the upper connector of the outer cylinder. A gasket is installed between the inner side of the lower end of the upper connector of the outer cylinder and the center rod through a countersunk pin; or / and, a cavity is provided on the inner side of the lower end of the plug, and the cavity is filled with sealing grease; or / and, the liner is made of high temperature and high pressure resistant material.

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