CN-121630344-B - Supercritical CO of deep coal seam2Pulse fracturing, permeability increasing and displacement gas device and method

CN121630344BCN 121630344 BCN121630344 BCN 121630344BCN-121630344-B

Abstract

The invention relates to the technical field of deep coal seam exploitation, in particular to a deep coal seam supercritical CO 2 pulse fracturing and permeability increasing displacement gas device and method. The device forms a main body frame through a cylindrical shell and an outer cylinder, and an excitation liquid carbon dioxide storage bin, a release assembly, a connecting assembly and a reinforcing assembly are arranged in the main body frame. Liquid CO 2 is injected into the storage bin through the infusion tube, high-pressure gaseous CO 2 is generated after phase change, the pushing rod is pushed by the hollow column to enable the inner barrel to slide, communication between the release inner hole and the release outer hole is achieved, and CO 2 is subjected to pulse impact coal seam fracturing and permeation increasing. The connecting component is matched with the arc-shaped block through the threaded sleeve plate to realize the stable connection of the cylindrical shell and the outer cylinder, and the reinforcing component is used for further enhancing the connection stability through the L-shaped clamping block. The device can effectively improve gas displacement efficiency, enlarges the displacement range, avoids loosening of the device due to factors such as vibration, pressure change and the like under the geological condition of complex deep coal seam, and ensures normal operation and safe production of the device.

Inventors

ZHAO XUN
DAI JIAXING
LIU XIANFENG
NIE BAISHENG
LI JIALIANG
DENG BOZHI
LIAO ZE
LI JIANGONG
LI QIHUI
XIE LIANGYU

Assignees

贵州理工学院
重庆大学

Dates

Publication Date: 20260508
Application Date: 20260202

Claims (8)

1. The deep coal seam supercritical CO 2 pulse fracturing permeation-increasing displacement gas device is characterized by comprising a cylindrical shell (1) and an outer cylinder (3), wherein an excited liquid carbon dioxide storage bin (20) is fixedly arranged in the cylindrical shell (1), a liquid CO 2 phase change excitation device is arranged in the excited liquid carbon dioxide storage bin (20), an end cover (5) is fixedly arranged at one end of the cylindrical shell (1), a liquid carbon dioxide infusion tube (6) is fixedly penetrated in the end cover (5), and the liquid carbon dioxide infusion tube (6) is fixedly communicated with the excited liquid carbon dioxide storage bin (20); A hollow tube (23) communicated with the end cover (5) is fixedly arranged at one end, far away from the end cover, of the excitation liquid carbon dioxide storage bin (20), and a fixed connecting block (21) communicated with the hollow tube (23) is fixedly arranged at one end, far away from the excitation liquid carbon dioxide storage bin (20); The inside release subassembly that is equipped with of urceolus (3), tubular casing (1) and urceolus (3) pass through coupling assembling and dismantle fixed connection, be equipped with the enhancement subassembly that is used for strengthening tubular casing (1) and urceolus (3) connection stability on fixed connection piece (21), liquid CO 2 is through liquid carbon dioxide transfer line (6) injection excitation liquid carbon dioxide storage storehouse (20), it produces high-pressure gaseous CO 2 to excite the phase transition through liquid CO 2 phase transition excitation device, high-pressure gaseous CO 2 carries to release subassembly through hollow tube (23), fixed connection piece (21), release by release subassembly to the coal seam in order to realize pulse fracturing and increase infiltration, the enhancement subassembly is including a plurality of spouts I (26) of opening in fixed connection piece (21) one end, every equal sliding connection has slider I (29) in spout I (26), the butt has compression spring (30) between slider I (29) and spout I (26) top inner wall, slider I (29) one end fixed mounting has L type fixture block (24), L type fixture block (24) bottom one side has seted up inclined plane (28), two inner sliding hole (32) are seted up to one side, two inner sliding hole (33) are connected to two inner side (32), the hollow column (27) is in sliding fit with the sliding groove II (32) through the sliding block II (34), the release assembly comprises an inner cylinder (14) which is in sliding connection with the inner wall of the outer cylinder (3), a plurality of connecting rods (16) are fixedly installed inside the inner cylinder (14), one end, close to each other, of each connecting rod (16) is fixedly provided with the same pushing rod (17), two symmetrical rectangular holes (35) are formed in the outer wall of the hollow column (27), a hollow groove (31) communicated with the rectangular holes (35) is formed in one end of the hollow column (27), one end of the hollow column (27) is matched with the inclined surface grooves (28), and the hollow column (27) and the pushing rods (17) are correspondingly arranged.
2. The deep coal seam supercritical CO 2 pulse fracturing permeation increasing displacement gas device according to claim 1, wherein a plurality of release inner holes (15) are formed in the outer wall of the inner cylinder (14), a plurality of release outer holes (7) are formed in the outer cylinder (3), and the release outer holes (7) are matched with the release inner holes (15); A tension spring (18) is connected between the inner cylinder (14) and an annular fixing plate I (13) fixedly arranged on the inner wall of the outer cylinder (3), the high-pressure gaseous CO 2 pushes a pushing rod (17) to drive the inner cylinder (14) to slide, a release inner hole (15) is communicated with a release outer hole (7) to release CO 2 , and the tension spring (18) can drive the inner cylinder (14) to reset.
3. The deep coal seam supercritical CO 2 pulse fracturing and permeability increasing displacement gas device according to claim 2, wherein the connecting component comprises a threaded sleeve plate (2), a threaded groove II (19) is formed in the outer wall of the cylindrical shell (1), a threaded groove I (8) is formed in the outer wall of the outer cylinder (3), and the threaded sleeve plate (2) is in threaded connection with the threaded groove I (8) and the threaded groove II (19); An annular fixing plate II (25) is rotationally connected inside the threaded sleeve plate (2), a plurality of arc blocks II (22) are fixedly arranged on the inner wall of the annular fixing plate II (25), and a plurality of arc blocks I (9) are fixedly arranged on the outer wall of the fixed connecting block (21); One end of the outer cylinder (3) close to the cylindrical shell (1) is provided with a plurality of arc-shaped notches (11), the inner part of the outer cylinder (3) is provided with an annular groove (12) communicated with the arc-shaped notches (11), the arc-shaped block I (9) is embedded into the annular groove (12) through the arc-shaped notch (11), and the arc-shaped block II (22) is clamped into the arc-shaped notch (11) and is clamped with the arc-shaped block I (9).
4. The deep coal seam supercritical CO 2 pulse fracturing permeation-increasing displacement gas device according to claim 3, wherein when high-pressure gaseous CO 2 is injected into the hollow groove (31) through the round hole (33), the rectangular hole (35) is attached to the inner wall of the round hole (33) to seal gas, the gas pressure pushes the hollow column (27) to transversely slide, the rectangular hole (35) is exposed out of the fixed connecting block (21) to release gas, and meanwhile the hollow column (27) presses the inclined surface groove (28) to drive the L-shaped clamping block (24) to abut against one side of the annular fixing plate I (13) away from the annular groove (12).
5. The deep coal seam supercritical CO 2 pulse fracturing and permeation increasing displacement gas device according to claim 4, wherein the cylindrical shell (1) is made of high-strength alloy steel, the outer cylinder (3) is made of ductile steel, and the inner cylinder (14) is made of wear-resistant alloy steel.
6. The deep coal seam supercritical CO 2 pulse fracturing and permeability increasing displacement gas device according to claim 5, wherein one end of the outer barrel (3) far away from the cylindrical shell (1) is connected with a connecting threaded block (10) through threads, and one end of the connecting threaded block (10) far away from the outer barrel (3) is fixedly provided with a fixed tip (4).
7. The deep coal seam supercritical CO 2 pulse fracturing and permeability increasing displacement gas device according to claim 6, wherein the number and the pore diameter of the release inner holes (15) and the release outer holes (7) are adjusted according to the geological conditions of the coal seam.
8. A deep coal seam supercritical CO 2 pulse fracturing and permeability increasing displacement gas method, which is characterized by adopting the device as claimed in claim 7 and comprising the following steps: s1, inserting the device into a coal seam drill hole through a fixed tip (4), and locking a threaded sleeve plate (2) through the cooperation of an arc-shaped block I (9) and an annular groove (12), so as to realize the fixed connection of a cylindrical shell (1) and an outer cylinder (3); S2, injecting liquid CO 2 into the excited liquid carbon dioxide storage bin (20) through a liquid carbon dioxide infusion tube (6), starting a liquid CO 2 phase change excitation device, and enabling liquid CO 2 to be phase-changed to generate high-pressure gaseous CO 2 ; S3, pushing the hollow column (27) to slide by high-pressure gas CO 2 , driving the L-shaped clamping block (24) to abut against the annular fixed plate I (13), pushing the pushing rod (17) to enable the inner cylinder (14) to slide, enabling the release inner hole (15) to be communicated with the release outer hole (7), releasing supercritical CO 2 fluid in a pulse mode, enabling a coal body to generate a fracture network with macroscopic cracks communicated with microscopic holes by utilizing a high-pressure gas wedge effect and a vibration wave effect, enabling supercritical CO 2 molecules to enter micropores of a coal matrix, converting adsorbed gas into free gas by replacement desorption, forming a high-speed seepage channel in the fracture network, and realizing deep fracturing and permeability increasing displacement of a coal seam; S4, connecting coal seam drilling holes through external extraction equipment, guiding out and collecting displaced gas through the drilling holes, reversely rotating the threaded sleeve plate (2) after operation is completed, and separating the cylindrical shell (1) from the outer cylinder (3) to detach the device.

Description

Deep coal seam supercritical CO 2 pulse fracturing, permeability increasing and displacement gas device and method Technical Field The invention relates to the technical field of deep coal seam exploitation, in particular to a deep coal seam supercritical CO 2 pulse fracturing and permeability increasing displacement gas device and method. Background In the deep coal seam exploitation process, the existence of gas not only seriously threatens the safe production of the coal mine, but also causes the waste of resources. The traditional gas displacement method has various limitations, such as low displacement efficiency, limited displacement range and the like, and is difficult to meet the requirement of high-efficiency exploitation of deep coal seams. Currently, some gas displacement devices are structurally inadequate. When the displacement medium is released, the release amount and the release direction of the partial device are difficult to control accurately, so that the displacement effect is poor. In addition, the connection stability between each part of the device is poor, and under the geological condition of deep coal seam complexity, the device is easy to loosen due to factors such as vibration, pressure change and the like, the normal operation of the device is influenced, and even safety accidents are caused. In addition, the operation of the existing gas displacement device in the mounting and dismounting processes is complex, a large amount of time and labor are consumed, and the working efficiency is reduced. Meanwhile, the device is poor in universality and is difficult to adapt to deep coal beds with different geological conditions and mining requirements. Therefore, research and development of the deep coal seam gas displacement device which can effectively improve the displacement efficiency, strengthen the connection stability of components, is convenient to mount and dismount and has good universality has important practical significance. Disclosure of Invention The invention aims to solve the defects that in the prior art, the connection stability between all parts of a device is poor, looseness is easy to occur due to factors such as vibration, pressure change and the like under the complex geological condition of a deep coal seam, the normal operation of the device is influenced, and even safety accidents are caused, and provides a deep coal seam supercritical CO 2 pulse fracturing and permeability increasing displacement gas device and method. In order to achieve the above purpose, the present invention adopts the following technical scheme: The deep coal seam supercritical CO 2 pulse fracturing permeation-increasing displacement gas device comprises a cylindrical shell and an outer cylinder, wherein an excitation liquid carbon dioxide storage bin is fixedly arranged in the cylindrical shell, and a liquid CO 2 phase change excitation device is arranged in the excitation liquid carbon dioxide storage bin; The end, far away from the end cover, of the excited liquid carbon dioxide storage bin is fixedly provided with a hollow tube communicated with the hollow tube, and the end, far away from the excited liquid carbon dioxide storage bin, of the hollow tube is fixedly provided with a fixed connecting block communicated with the hollow tube; the inner part of the outer cylinder is provided with a release assembly, the cylindrical shell is detachably and fixedly connected with the outer cylinder through a connecting assembly, and the fixed connecting block is provided with a reinforcing assembly for reinforcing the connection stability of the cylindrical shell and the outer cylinder; The liquid CO 2 is injected into the liquid carbon dioxide storage bin through the liquid carbon dioxide infusion tube, the liquid CO 2 phase change excitation device excites phase change to generate high-pressure gaseous CO 2, the high-pressure gaseous CO 2 is conveyed to the release assembly through the hollow tube and the fixed connecting block, the release assembly releases the high-pressure gaseous CO 2 to the coal seam to realize pulse fracturing and permeability increasing, and the reinforcing assembly can avoid loosening of the device under complex geological conditions. In one possible design, the release assembly comprises an inner cylinder which is connected with the inner wall of the outer cylinder in a sliding way, wherein a plurality of connecting rods are fixedly arranged in the inner cylinder, and one pushing rod is fixedly arranged at one end of each connecting rod, which is close to each other; A tension spring is connected between the annular fixing plate I fixedly arranged on the inner wall of the inner cylinder and the inner wall of the outer cylinder, the high-pressure gaseous CO 2 pushes the pushing rod to drive the inner cylinder to slide, the release inner hole is communicated with the release outer hole to release CO 2, and the tension spring can drive the inner cylinder to reset. In