A process method of phase change detonation directional metal jet for increasing permeation

Abstract

The application provides a phase-change detonation directional metal jetting permeability enhancement process method, which is suitable for coal seam roof and floor rock mass and medium-hard coal body. Single or multiple phase-change detonation metal jetting equipment is installed on a drill rod and pushed into a target area, and the target area is subjected to directional pressure relief and permeability enhancement by using the phase-change detonation metal jetting equipment. The phase-change detonation metal jetting equipment comprises a pressure-bearing packer, a perforator and a gas tank, the gas tank is filled with liquid carbon dioxide, and a phase-change exciter and a phase-change instantaneous delay exciter are arranged on the gas tank. The liquid carbon dioxide is excited to change into a gaseous state, high-pressure detonation energy is generated, a bullet head is directed to jet into the target area, and a permeability enhancement hole is formed. Single or multiple continuous composite permeability enhancement can be realized, and the permeability of the coal seam is improved. The phase-change detonation directional metal jetting equipment has a reasonable structure, is easy to operate, has a wide application range, and can effectively improve the gas extraction rate and the mining safety. The application has the advantages of high efficiency, safety and controllability, overcomes the limitations of traditional permeability enhancement methods, has a remarkable permeability enhancement effect, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mining and relates to a phase change detonation directional metal jet infiltration process method. Background Art

[0002] Most of my country's deep coal seams are mainly low in permeability. In the process of coal mine gas control, coal seam permeability is one of the main factors affecting the gas extraction rate. In order to efficiently extract gas and safely mine and produce coal, hydraulic fracturing, hydraulic cutting and gas phase change fracturing and other permeability enhancement methods are currently widely used in coal mines.

[0003] Hydraulic fracturing technology, however, has its limitations. Hydraulic fracturing in coal seams increases permeability within rock and coal pores. Using high-pressure fracturing can lead to irregular fractures in the rock pores. As fractures penetrate the rock mass and penetrate deep into the coal, fractures also occur in the coal seam roof, leading to irregular extension of fractures in high-pressure areas. While hydraulic fracturing can effectively extract and absorb gas within the increased permeability zone, improving gas extraction rates, the strong shock waves generated during operation can easily induce drill bit sticking, compromising the permeability enhancement effect.

[0004] Gas phase change fracturing is a method used in coal mines to improve mining efficiency and safety. This technology utilizes the phase change properties of gas. By injecting high-pressure gas or gas mixtures, it induces a phase change within the coal fissures, generating significant pressure that cracks the coal and achieves a fracturing effect. Gas phase change fracturing also results in irregular crack extension during the permeability enhancement process in rock and coal.

[0005] All of the above permeability enhancement methods struggle to achieve efficient and continuous processes, and the resulting fractures in the coal and rock pores are often irregular. Therefore, the key challenge in the field application of existing permeability enhancement methods is how to target fractures in the target area and expand and extend the pores and fractures in the coal and rock mass while ensuring full development. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to solve the above problems and provide a phase change detonation directional metal jet infiltration process method.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A phase change detonation directional metal jet permeability enhancement process method targets coal seam roof and floor rock mass and / or medium-hard coal mass. A single set or multiple sets of phase change detonation metal jet equipment are installed on a drill pipe and pushed into the target area using the drill pipe. The phase change detonation metal jet equipment is used to perform directional pressure relief and permeability enhancement in the target area.

[0009] The phase change detonation metal jet equipment includes a pressure-bearing isolation device connected to the drill pipe and a perforator. The pressure-bearing isolation device is located at the rear end of the perforator and is used to seal the perforator within the drill hole. The perforator is provided with a detonation chamber inside. The side wall of the perforator is provided with a plurality of bullet holes connected to the detonation chamber. The bullet holes are provided with bullet heads to seal the detonation chamber. The two ends of the perforator are each detachably connected to a gas tank. Both gas tanks contain liquid carbon dioxide, one of which is provided with a phase change exciter, and the other is provided with a phase change instantaneous delay exciter.

[0010] A barrier pad is provided between each of the two gas storage tanks and the detonation chamber. The barrier pad fails at a set pressure, thereby connecting the inner cavity of the gas storage tank to the detonation chamber. The phase change exciter and the phase change instantaneous delay exciter are both used to excite the liquid carbon dioxide in the gas storage tank to a gaseous state, and the excitation time of the phase change instantaneous delay exciter is later than that of the phase change exciter.

[0011] After the phase change exciter is activated, the liquid carbon dioxide in the corresponding gas tank is changed into a gaseous state. The high-pressure detonation energy generated breaks through the barrier pad and enters the perforator to directionally eject the bullet head into the target area, thereby generating a first permeation-increasing hole in the target area. The phase change instantaneous delay exciter is activated after a set delay, and the liquid carbon dioxide in the corresponding gas tank is changed into a gaseous state. The high-pressure detonation energy generated breaks through the barrier pad and enters the first permeation-increasing hole through the bullet hole on the perforator, thereby performing a second fracture-increasing permeation on the target area.

[0012] Furthermore, for medium-hard coal bodies, a drilling rig and low-pressure water are used to drill a hole in the coal seam with a construction length of no more than 100m into the medium-hard coal body. After drilling to the target length, the drill rod is withdrawn and the low-pressure water is turned off. The phase change detonation metal jet device is pushed in by connecting the drill rod with the drilling rig. After reaching the target position, the internal borehole space is sealed using a pressure-bearing sealing device, and the device is oriented using a positioning device. Finally, the phase change detonation metal jet is excited to perform composite permeability enhancement, thereby achieving large-area pressure relief and permeability enhancement around the borehole under the medium-hard coal body.

[0013] Furthermore, for the coal seam roof and floor rock mass, a directional drilling rig is used to drill holes with a construction length greater than 100m and a depth; after drilling to the target length, the drill rod is withdrawn, and a drilling rig is used to connect the drill rod and push in multiple phase change detonation metal jet devices in series; after reaching the target position, the internal borehole space is sealed, and after determining the position, multiple phase change detonation metal jets are excited to perform composite permeability enhancement, thereby realizing directional pressure relief and permeability enhancement in the coal seam roof and floor rock mass drilling holes.

[0014] Furthermore, one or more pressure relief and permeability enhancement operations are performed according to the permeability enhancement area, and a backward permeability enhancement process is adopted in the rock mass and coal mass of the coal seam roof and floor, and the device is safely recovered after the process is completed.

[0015] Furthermore, after the drilling is completed, the drill cuttings in the drilling hole are cleaned; the overall length of the phase change detonation metal jet device used is 1.2m.

[0016] Furthermore, in the phase change detonation metal jet equipment, the two gas storage tanks are provided with a filling device at one end away from the perforator, and the filling device is provided with an injection hole and a drainage hole. One end of the filling device is connected to the gas storage tank, and the other end is provided with a sealing plug sealedly connected thereto; the pressure-bearing sealing device includes at least two pressure-bearing sealers arranged at intervals, and the pressure-bearing sealer close to the filling device is detachably connected to the filling device adjacent thereto.

[0017] Furthermore, the connections between the drill pipe, the pressure-bearing isolation device, the sealing plug, the filling device, the gas storage tank, and the perforator are threaded; and sealing rings are also provided at the connections between the sealing plug, the filling device, the gas storage tank, and the perforator.

[0018] Furthermore, the bullet hole extends and protrudes 2 cm from the outer wall of the perforator; and the bullet head is a metal bullet head.

[0019] Furthermore, in the phase change detonation metal jet equipment, the gas storage capacity of liquid carbon dioxide in the gas tank equipped with the phase change exciter is smaller than the gas storage capacity of liquid carbon dioxide in the gas tank equipped with the phase change instantaneous delay exciter, and the gas storage capacity ratio of the two is 1:1.5 to 1:2.

[0020] Furthermore, in the phase change detonation metal jet equipment, the excitation time interval between the phase change exciter and the phase change instantaneous delay exciter is 1s; the two barrier pads have different pressure bearing capacities, and the ultimate pressure bearing capacity of the barrier pad close to the phase change instantaneous delay exciter is greater than the ultimate pressure bearing capacity of the barrier pad close to the phase change exciter.

[0021] The beneficial effects of the present invention are:

[0022] 1. Improved permeability: By employing phase-change detonation technology, a directional, high-pressure metal jet is generated within the roof and floor rock mass of the coal seam and within the medium-hard coal mass, thereby forming fracture pores and permeability-enhancing pores. Compared to traditional hydraulic fracturing and gas phase-change fracturing technologies, this method can more effectively form a regular fracture network within the target area, significantly improving the permeability of the coal seam.

[0023] 2. Strong directional control capability: The present invention installs single or multiple phase change detonation metal jet equipment on the drill pipe and utilizes pressure-bearing isolation devices and positioning devices to achieve precise positioning of the target area and directional pressure relief and permeability enhancement, thus avoiding the problem of irregular crack extension in traditional methods and improving the controllability of the fracturing effect.

[0024] 3. Reduce operational risks: Phase change detonation metal jet technology can achieve efficient permeability enhancement under low-pressure conditions, avoiding the rupture of the coal seam roof area and the drill holding phenomenon caused by strong shock waves during high-pressure hydraulic fracturing, reducing operational risks and improving construction safety.

[0025] 4. Wide range of applications: This invention is applicable not only to permeability enhancement operations in medium-hard coal, but also to permeability enhancement operations in coal seam roof and floor rock. By connecting multiple phase change detonation metal jet devices in series, continuous composite permeability enhancement can be achieved over large areas, improving the applicability and flexibility of the process.

[0026] 5. Efficient and continuous operation: The phase change detonation directional metal jet equipment of the present invention can achieve single or multiple continuous composite infiltration operations, improving construction efficiency. At the same time, after the process is completed, the device can be safely recovered, facilitating subsequent operation and maintenance.

[0027] 6. Significant permeability enhancement: By utilizing phase change detonation technology and metal jet equipment, this invention generates high-pressure detonation energy within the target area, injecting metal projectiles in a targeted manner to create fracture-inducing and permeability-enhancing pores. Multiple activations and combined permeability enhancement operations further expand the fracture network, improving coal seam permeability and gas extraction efficiency, resulting in significant permeability enhancement.

[0028] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0030] Figure 1 It is a schematic flow chart of the phase change detonation directional metal jet infiltration process method of the present invention.

[0031] Figure 2 It is a schematic diagram of the phase change detonation metal jet equipment in the present invention.

[0032] Figure 3 Schematic diagram of the structure of the perforator.

[0033] Figure markings: 1-first pressure-bearing sealer; 2-second pressure-bearing sealer; 3-sealing plug; 4-filling device; 5-sealing ring; 6-phase change activator; 7-first air tank; 8-barrier pad; 9-perforator; 10-second air tank; 11-phase change instantaneous delay activator; 12-sealing plug; 13-bullet head. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0036] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0037] Please refer to Figures 1 to 3 It is a phase change detonation directional metal jet permeability enhancement process method. For the coal seam roof and floor rock mass and / or medium-hard coal body, a single set or multiple sets of phase change detonation metal jet equipment are installed on the drill pipe, and the drill pipe is pushed into the target area. The phase change detonation metal jet equipment is used to carry out directionally depressurized and permeated the target area.

[0038] The phase change detonation metal jet equipment includes a pressure-bearing isolation device and a perforator 9 connected to the drill pipe. The pressure-bearing isolation device is provided at the rear end of the perforator 9 and is used to seal the perforator 9 in the borehole. A detonation chamber is provided inside the perforator 9, and a number of bullet holes connected to the detonation chamber are provided on the side wall of the perforator 9. The bullet holes extend and protrude 2 cm from the outer wall of the perforator 9. A bullet head 13 is provided in the bullet hole to seal it. The bullet head 13 is a metal bullet. Two gas tanks are connected to the two ends of the perforator 9 by threads, namely the first gas tank 7 and the second gas tank 10. Liquid carbon dioxide is contained in the first gas tank 7 and the second gas tank 10. A phase change exciter 6 is installed in the first gas tank 7, and a phase change instantaneous delay exciter 11 is installed in the second gas tank 10.

[0039] A barrier pad 8 is provided between the first gas storage tank 7, the second gas storage tank 10 and the detonation chamber. The barrier pad 8 fails under a set pressure, connecting the inner cavity of the gas storage tank to the detonation chamber. The phase change exciter 6 and the phase change instantaneous delay exciter 11 are both used to excite the liquid carbon dioxide in the gas storage tank to a gaseous state, and the excitation time of the phase change instantaneous delay exciter 11 is later than that of the phase change exciter 6.

[0040] After the phase change exciter 6 is started, the liquid carbon dioxide in the corresponding gas tank is changed into gas. The high-pressure detonation energy generated breaks through the barrier pad 8, enters the perforator 9, and sprays the bullet head 13 into the permeability-enhancing coal seam in a direction, thereby generating the first permeability-enhancing hole in the coal seam; the phase change instantaneous delay exciter 11 is started after the set delay, and the liquid carbon dioxide in the corresponding gas tank is changed into gas. The high-pressure detonation energy generated breaks through the barrier pad 8, enters the first permeability-enhancing hole through the bullet hole on the perforator 9, and performs a second fracture and permeability-enhancing operation on the coal seam.

[0041] The two gas storage tanks are both provided with a filling device 4 at one end away from the perforator 9. The filling device 4 is provided with a liquid injection hole and a liquid discharge hole. One end of the filling device 4 is connected to the gas storage tank, and the other end is provided with a sealing plug sealed therewith.

[0042] The pressure-bearing sealing device comprises a first pressure-bearing sealer 1 and a second pressure-bearing sealer 2 which are spaced apart from each other, and the second pressure-bearing sealer 2 is detachably connected to a filling device 4 adjacent thereto.

[0043] The connections among the drill pipe, the pressure-bearing isolation device, the sealing plug, the filling device 4, the gas storage tank and the perforator 9 are threaded and can be disassembled and replaced.

[0044] Sealing rings are also provided at the connections between the sealing plug, the filling device 4, the gas storage tank and the perforator 9 to seal the connections.

[0045] The liquid carbon dioxide storage volume within the gas tank equipped with the phase-change exciter 6 is smaller than the liquid carbon dioxide storage volume within the gas tank equipped with the phase-change instantaneous delay exciter 11, with the ratio between the two volumes being 1:1.5 to 1:2. The two barrier pads 8 have different pressure-bearing capacities: the barrier pad 8 on the side closest to the phase-change instantaneous delay exciter 11 has a greater ultimate pressure-bearing capacity than the barrier pad 8 on the side closest to the phase-change exciter 6.

[0046] The excitation time interval between the phase change exciter 6 and the phase change instantaneous delay exciter 11 is 1 s.

[0047] For medium-hard coal bodies, a drilling rig and low-pressure water are used to drill a hole in the coal seam with a construction length of no more than 100m. After drilling to the target length, the drill pipe is withdrawn and the low-pressure water is turned off. The phase change detonation metal jet device is pushed in by connecting the drill pipe with the drilling rig. After reaching the target position, the internal drilling space is sealed using a pressure-bearing sealing device, and the device is oriented using a positioning device. Finally, the phase change detonation metal jet is stimulated to perform composite permeability enhancement, thereby achieving large-area pressure relief and permeability enhancement around the drill hole under the medium-hard coal body.

[0048] For the coal seam roof and floor rock mass, a directional drilling rig is used to drill holes with a construction length greater than 100m and a depth; after drilling to the target length, the drill rod is withdrawn, and a drilling rig is used to connect the drill rod and push in multiple phase change detonation metal jet devices in series; after reaching the target position, the internal borehole space is sealed, and after determining the position, multiple phase change detonation metal jets are stimulated to perform composite permeability enhancement, thereby achieving directional pressure relief and permeability enhancement in the coal seam roof and floor rock mass drilling holes.

[0049] After drilling is complete, drill cuttings are cleaned from the borehole. The phase change detonation metal jet device used is 1.2 meters long. One or more pressure relief and permeability enhancement operations are performed depending on the permeability enhancement area. A backward permeability enhancement process is used in both the roof and floor rock mass and the coal body. After the process is complete, the device is safely recovered.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A phase change detonation directional metal jet infiltration process, characterized by: For coal seam roof and floor rock mass and / or medium-hard coal mass, a single set or multiple sets of phase change detonation metal jet equipment are installed on the drill pipe, and the drill pipe is pushed into the target area to carry out directional pressure relief and permeability enhancement in the target area through the phase change detonation metal jet equipment; The phase change detonation metal jet equipment includes a pressure-bearing isolation device connected to the drill pipe and a perforator. The pressure-bearing isolation device is located at the rear end of the perforator and is used to seal the perforator within the drill hole. The perforator is provided with a detonation chamber inside. The side wall of the perforator is provided with a plurality of bullet holes connected to the detonation chamber. The bullet holes are provided with bullet heads to seal the detonation chamber. The two ends of the perforator are each detachably connected to a gas tank. Both gas tanks contain liquid carbon dioxide, one of which is provided with a phase change exciter, and the other is provided with a phase change instantaneous delay exciter. A barrier pad is provided between each of the two gas storage tanks and the detonation chamber. The barrier pad fails at a set pressure, thereby connecting the inner cavity of the gas storage tank to the detonation chamber. The phase change exciter and the phase change instantaneous delay exciter are both used to excite the liquid carbon dioxide in the gas storage tank to a gaseous state, and the excitation time of the phase change instantaneous delay exciter is later than that of the phase change exciter. After the phase change exciter is activated, the liquid carbon dioxide in the corresponding gas tank is changed into a gaseous state. The high-pressure detonation energy generated breaks through the barrier pad and enters the perforator to directionally eject the bullet head into the target area, thereby generating a first permeation-increasing hole in the target area. The phase change instantaneous delay exciter is activated after a set delay, and the liquid carbon dioxide in the corresponding gas tank is changed into a gaseous state. The high-pressure detonation energy generated breaks through the barrier pad and enters the first permeation-increasing hole through the bullet hole on the perforator, thereby performing a second fracture-increasing permeation on the target area.

2. The phase change detonation directional metal jet infiltration process according to claim 1, characterized in that: For medium-hard coal bodies, a drilling rig and low-pressure water are used to drill a hole in the coal seam with a construction length of no more than 100m. After drilling to the target length, the drill pipe is withdrawn and the low-pressure water is turned off. The phase change detonation metal jet device is pushed in by connecting the drill pipe with the drilling rig. After reaching the target position, the internal drilling space is sealed using a pressure-bearing sealing device, and the device is oriented using a positioning device. Finally, the phase change detonation metal jet is stimulated to perform composite permeability enhancement, thereby achieving large-area pressure relief and permeability enhancement around the drill hole under the medium-hard coal body.

3. The phase change detonation directional metal jet infiltration process according to claim 1, characterized in that: For the coal seam roof and floor rock mass, a directional drilling rig is used to drill holes with a construction length greater than 100m and a depth; after drilling to the target length, the drill rod is withdrawn, and a drilling rig is used to connect the drill rod and push in multiple phase change detonation metal jet devices in series; after reaching the target position, the internal borehole space is sealed, and after determining the position, multiple phase change detonation metal jets are stimulated to perform composite permeability enhancement, thereby achieving directional pressure relief and permeability enhancement in the coal seam roof and floor rock mass drilling holes.

4. The phase change detonation directional metal jet infiltration process according to claim 2 or 3, characterized in that: One or more pressure relief and permeability enhancement operations are carried out according to the permeability enhancement area, and the backward permeability enhancement process is adopted in the rock mass and coal mass of the coal seam roof and floor. After the process is completed, the device is safely recovered.

5. The phase change detonation directional metal jet infiltration process according to claim 2, characterized in that: After the drilling is completed, the drill cuttings in the drilling hole are cleaned; the overall length of the phase change detonation metal jet device used is 1.2m.

6. The phase change detonation directional metal jet infiltration process according to claim 1, characterized in that: In the phase change detonation metal jet equipment, the two gas storage tanks are each provided with a filling device at one end away from the perforator, and the filling device is provided with an injection hole and a drainage hole. One end of the filling device is connected to the gas storage tank, and the other end is provided with a sealing plug sealedly connected thereto; the pressure-bearing sealing device includes at least two pressure-bearing sealers arranged at intervals, and the pressure-bearing sealer close to the filling device is detachably connected to the filling device adjacent thereto.

7. The phase change detonation directional metal jet infiltration process according to claim 6, characterized in that: The connections among the drill pipe, pressure-bearing isolation device, sealing plug, filling device, gas storage tank and perforator are threaded; the connections among the sealing plug, filling device, gas storage tank and perforator are also provided with sealing rings.

8. The phase change detonation directional metal jet infiltration process according to claim 1, characterized in that: The bullet hole extends and protrudes 2 cm from the outer wall of the perforator; the bullet head is a metal bullet head.

9. The phase change detonation directional metal jet infiltration process according to claim 1, characterized in that: In the phase change detonation metal jet equipment, the gas storage volume of liquid carbon dioxide in the gas tank equipped with the phase change exciter is smaller than the gas storage volume of liquid carbon dioxide in the gas tank equipped with the phase change instantaneous delay exciter, and the gas storage volume ratio between the two is 1:1.5 to 1:

2.

10. The phase change detonation directional metal jet infiltration process according to claim 1, characterized in that: In the phase change detonation metal jet equipment, the excitation time interval between the phase change exciter and the phase change instantaneous delay exciter is 1s; the two barrier pads have different pressure bearing capacities, and the ultimate pressure bearing capacity of the barrier pad close to the phase change instantaneous delay exciter is greater than the ultimate pressure bearing capacity of the barrier pad close to the phase change exciter.

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