A fully enclosed core sampling device

Abstract

A fully enclosed core sampling device comprises an outer tube of a drill tool, an inner tube of a drill tool and a drill bit, wherein the outer tube of the drill tool is connected to the drill bit, the inner tube of the drill tool is connected to the upper part of a core pipe joint, the lower part of the core pipe joint is connected to a sampler, the sampler comprises a spring seat, a support seat, a flap claw and a spring sheet, the support seat is located in the spring seat, the upper part of the spring seat is threadedly connected to the core pipe joint, a support platform is provided in the spring seat, the support seat is located in the spring seat and supported by the support platform, the flap claw is provided with several pieces, the outer wall of each flap claw is fixed with a spring sheet, each flap claw can be opened and closed relative to the support seat, each flap claw forms a closed curved surface in the shape of a bullet in the closed state, and each flap claw squeezes the spring sheet in the fully open state. The present invention is designed for the core sampling requirements of fluid formations such as shallow marine layers, silt, quicksand, etc., and can obtain a good core sampling effect for "fluid" cores and rock samples, ensure the core sampling rate of fluid formations, and greatly improve the core sampling quality of fluid formations.

Description

Technical Field

[0001] The invention relates to a drilling core sampling device, in particular to a fully enclosed core sampling device for complex strata such as shallow marine layers, silt, quicksand, etc. Background Art

[0002] With the expansion of the field of marine drilling, the requirements of marine drilling technology for core sampling are becoming higher and higher. In shallow marine and energy exploration drilling, silt, water-sensitive, silty sand and other formations that are difficult to ensure the quality of core sampling (sampling) are often encountered. The formation conditions in the ocean are more complex and harsh, and the sand particles are finer. The cores or rock samples taken out often present a form similar to "fluid", which is called "fluid-like" core. The claw spring commonly used in land sampling devices has a very limited coring effect for such cores or rock samples due to poor blocking effect. In addition, the existing core sampling device is affected by the structural design. During use, the spring claw of the claw spring will cause a large disturbance to the core or rock sample when the core or rock sample passes through the claw spring, making it difficult to obtain sufficient and qualified cores required for drilling. In view of this, it is necessary to study new sampling devices to meet the sampling requirements of fluid-like formations. Summary of the invention

[0003] The purpose of the present invention is to provide a fully enclosed core sampling device which can effectively prevent the loss of fluid rock samples and ensure the core sampling rate of fluid formations in view of the shortcomings of the prior art.

[0004] The problem described in the present invention is solved by the following technical solution:

[0005] A fully enclosed core sampling device comprises an outer tube of a drill tool, an inner tube of a drill tool, a sampler and a drill bit, wherein the outer tube of the drill tool is connected to the drill bit, the inner tube of the drill tool is connected to the upper part of a core pipe joint, and the lower part of the core pipe joint is connected to the sampler, and the sampler comprises a spring seat, a support seat, a petal claw and a spring sheet, wherein the support seat is located in the spring seat, the upper part of the spring seat is threadedly connected to the core pipe joint, a support platform is provided in the spring seat, and the support seat is supported by the support platform, wherein several petal claws are arranged, and a spring sheet is fixed on the outer wall of each petal claw, and each petal claw can be opened and closed relative to the support seat, and each petal claw forms a closed curved surface in the shape of a bullet in a closed state, and each petal claw squeezes the spring sheet in a fully open state.

[0006] The fully enclosed core sampling device has a claw mounting ring at the root of each claw, and the support seat mounting ring is distributed on the upper end surface of the support seat. The steel wire shaft passes through each claw mounting ring and the support seat mounting ring to hinge each claw to the support seat.

[0007] The fully enclosed core sampling device has claws made of metal, with cutting edges on the sides of the claws, protrusions and grooves on the cutting edges, and the grooves and protrusions of adjacent claws in the closed state of each claw being mortise and tenoned with each other.

[0008] In the above-mentioned fully enclosed core sampling device, the angle a between the spring sheet and the outer wall of the claw is 20°-45°.

[0009] In the fully enclosed core sampling device, a flat groove is provided on the back of each claw, a spring sheet is located in the flat groove, and the spring sheet is connected to the claw via a rivet.

[0010] The fully enclosed core sampling device has an inner wall of the drill bit provided with a supporting step, the supporting step is an inclined step, and the spring retaining seat is provided with an external clamping platform, which matches and fits the supporting step.

[0011] In the above-mentioned fully enclosed core sampling device, the aperture of the support seat matches the aperture of the lower part of the spring-stop seat, and the aperture of the lower part of the spring-stop seat is not less than the aperture of the working end of the drill bit.

[0012] The fully enclosed core sampling device, the sampler also includes a support retaining ring, the support retaining ring is located in the spring seat, the upper and lower end surfaces of the support retaining ring are respectively in contact with the lower end surface of the core pipe joint and the upper end surface of the support seat.

[0013] The fully enclosed core sampling device has 3 to 8 claws; the curved surface vertex angle formed by the closed claws is 90 to 150 degrees.

[0014] The present invention is designed for the core sampling requirements of shallow marine, silt, quicksand and other fluid formations. Through the setting of petal-shaped claws, when the core and rock sample pass through, the claws are fully opened close to the inner wall of the spring seat, and the inner diameter of the channel formed is equal to or greater than the outer diameter of the core, which minimizes the disturbance to the core and rock sample; when the drilling is completed and the drill is lifted, the claws are closed, and there is no gap between adjacent claws, so the channel is fully closed to ensure that sufficient cores and rock samples are obtained. In addition, the drill bit water channel of the present invention adopts a side hole bottom spray type, and the outer structure of the spring seat and the inner structure of the drill bit are designed to match, which can maximize the avoidance of erosion of the core by the flushing fluid, further ensuring the quality of coring. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings.

[0016] Figure 1 It is a schematic diagram of the structure of the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the sampler;

[0018] Figure 3 is a schematic diagram of the closed state of the sampler's valve claws;

[0019] Figure 4 It is a schematic diagram of the sampler's flap claws in a fully opened state;

[0020] Figure 5 It is a schematic diagram of the structure of the valve claw;

[0021] Figure 6 yes Figure 5 Rear view of

[0022] Figure 7-Figure 9 It is a schematic diagram of the working process of the present invention.

[0023] The numbers in the figure are: 1, drill tool outer tube, 2, drill tool inner tube, 3, core pipe joint, 4, drill bit, 4-1, support step, 5, spring seat, 6, support retaining ring, 7, spring sheet, 8, valve claw, 8-1, groove, 8-2, protrusion, 8-3, flat groove, 8-4, valve claw mounting ring, 9, wire shaft, 10, support seat, 11, external clamping table, 12, core column. DETAILED DESCRIPTION

[0024] See also Figure 1 The present invention comprises a drilling tool outer tube 1, a drilling tool inner tube 2, a drill bit 4, a core pipe joint 3 and a sampler. The lower part of the drilling tool outer tube is connected to the drill bit, the drilling tool inner tube is located inside the drilling tool outer tube, and the drilling tool inner tube is connected to the upper part of the core pipe joint.

[0025] See also Figure 2-Figure 4 The sampler includes a spring seat 5, a support seat 10, a petal claw 8, a support retaining ring 6 and a spring sheet 7. The spring seat is a hollow structure. The upper part of the spring seat is threadedly connected to the lower part of the core pipe joint. A support platform is arranged inside the spring seat. The support seat is cylindrical. The support seat is located inside the spring seat, and the bottom of the support seat is supported by the support platform. The support retaining ring is located inside the spring seat. The upper and lower end faces of the support retaining ring respectively contact the lower end face of the core pipe joint and the upper end face of the support seat. The support retaining ring limits the axial position of the support seat to prevent the support seat from moving during the drilling process. There are 3-8 petal claws, and a spring sheet is fixed on the outer wall of each petal claw. A petal claw mounting ring 8-4 is arranged at the root of each petal claw. Support seat mounting rings are distributed on the upper end face of the support seat. The wire shaft 9 passes through each petal claw mounting ring and the support seat mounting ring to hinge each petal claw with the support seat. The above structure enables each petal claw to be opened or closed relative to the support seat. The closed state of each petal claw is as follows Figure 3 The closed curved surface in the shape of a bullet shown in the figure has a vertex angle of 90-150 degrees. When each claw is fully opened, the spring sheet is pressed to contact the inner wall of the support retaining ring, the claw is in a vertical state, and the aperture formed by the inner wall of the claw matches the aperture of the support seat, such as Figure 4 As shown in the figure. In the natural state where the spring sheet is not compressed, the spring sheet and the outer wall of the claw form an angle a. If the angle is too large, the spring sheet will be compressed too early during the opening process of the claw, increasing the opening resistance of the claw and causing disturbance to the core; if the angle is too small, it will be unfavorable for the claw to start closing. Taking all factors into consideration, the value of a should be controlled at 20-45°.

[0026] See also Figure 5 , Figure 6The claw 8 is made of metal. In order to reduce the resistance of cutting the core during the closing process of the claw, a cutting edge is provided on the side of the claw. In order to ensure the tightness between adjacent claws in the closed state of the claw and avoid leakage of fluid core, a protrusion 8-2 and a groove 8-1 are provided at the cutting edge of the claw. The grooves and protrusions of adjacent claws in the closed state of each claw are mortise and tenoned with each other. A flat groove 8-3 is provided on the back of each claw. The spring sheet is located in the flat groove and connected by rivets. The unfolded length of the spring sheet should be lower than the top of the claw.

[0027] See also Figure 1 The inner wall of the drill bit is provided with a support step, which is an inclined step. The spring seat is provided with an external clamping platform 11, which matches and closely fits the support step. This structure allows the flushing fluid to pass through the side channel of the drill bit instead of flowing through the internal annular gap of the drill bit, thereby avoiding the erosion of the core by the flushing fluid to the greatest extent and further ensuring the quality of coring. The aperture of the support seat matches the aperture of the lower part of the spring seat, and the aperture of the lower part of the spring seat is not less than the aperture of the working end of the drill bit. In this way, when the claws are fully opened, the inner diameter of the channel formed by the sampler is equal to or greater than the outer diameter of the core, which minimizes the disturbance to the core and ensures the integrity of the core.

[0028] See also Figure 7-Figure 9 The working process of the present invention is as follows: during drilling, as the drill bit rotates and cuts downward, the formed core column 12 pushes the claws upward, and the claws open a certain angle around the wire shaft under the action of this thrust, such as Figure 7 As shown in the figure, as the drilling progresses downward, the claws gradually open, and the spring sheet is forced to deform to store elastic potential energy until the claws are close to the inner wall of the support ring. Figure 8 As shown in the figure, at the end of each drilling, the core or rock sample needs to be taken. When the drill tool is lifted off the bottom of the hole, the claw assembly tends to close inward under the action of the deformed spring sheet. As the drill tool is lifted, the core column moves relative to the inner tube of the drill tool. This relative movement causes the core column to further press the claw. The cutting edge on the claw can easily cut into and finally cut off the core column. After that, the claw is completely closed. Fig. 9 The tightly closed state of the claws can effectively prevent the loss of fluid rock samples, thereby ensuring the core recovery rate in such formations.

Claims

1. A fully enclosed core sampling device, comprising a drill tool outer tube (1), a drill tool inner tube (2), a sampler and a drill bit (4), wherein the drill tool outer tube is connected to the drill bit, the drill tool inner tube is connected to the upper part of a core pipe joint (3), and the lower part of the core pipe joint is connected to the sampler, characterized in that: The sampler comprises a spring seat (5), a support seat (10), a petal claw (8) and a spring sheet (7), wherein the support seat is located inside the spring seat, the upper part of the spring seat is threadedly connected to the core pipe joint, a support platform is provided inside the spring seat, the support seat is supported by the support platform, a plurality of petal claws are provided, the spring sheet is fixed on the outer wall of each petal claw, each petal claw can be opened and closed relative to the support seat, each petal claw forms a closed curved surface in the shape of a bullet in a closed state, and each petal claw squeezes the spring sheet in a fully open state; A flap claw mounting ring (8-4) is provided at the root of each flap claw, a support seat mounting ring is distributed on the upper end surface of the support seat, and a steel wire rotating shaft (9) passes through each flap claw mounting ring and the support seat mounting ring to hinge each flap claw with the support seat; The petal claws are made of metal, and the sides of the petal claws are provided with cutting edges, and the cutting edges are provided with protrusions (8-2) and grooves (8-1), and when each petal claw is in a closed state, the grooves and protrusions of adjacent petal claws are mortise-tenoned with each other; A flat groove (8-3) is provided on the back of each petal claw, a spring sheet is located in the flat groove, the spring sheet is connected via rivets, and the unfolded length of the spring sheet is lower than the top of the petal claw; The included angle a between the spring sheet and the outer wall of the claw is 20°-45°; The inner wall of the drill bit is provided with a supporting step, the supporting step is an inclined step, and the spring retaining seat is provided with an external clamping platform (11), the external clamping platform matches and fits the supporting step; The sampler also includes a support retaining ring (6), which is located in the spring seat, and the upper and lower end surfaces of the support retaining ring are respectively in contact with the lower end surface of the core pipe joint and the upper end surface of the support seat; The aperture of the support seat matches the aperture of the lower part of the spring stop seat, and the aperture of the lower part of the spring stop seat is not less than the aperture of the working end of the drill bit.

2. The fully enclosed core sampling device according to claim 1, characterized in that: There are 3 to 8 claws; the top angle of the curved surface formed by the closed claws is 90° to 150°.

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