CN115822528B - Coal bed gas exploitation method for water-gas two-phase variable-temperature fracturing displacement - Google Patents
Coal bed gas exploitation method for water-gas two-phase variable-temperature fracturing displacement Download PDFInfo
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Abstract
The invention belongs to the technical field of coal exploitation and coalbed methane exploitation, and particularly relates to a coalbed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement. The permeability-increasing principle of the mining method is that the gas pressure in a drill hole is increased firstly, the gas permeability of a coal seam is increased in a small range, then the water content of the coal seam is increased to enable liquid water stored in pores to be changed into solid ice so as to continue permeability increase, then the solid water is liquefied or gasified through high-temperature gas injection, so that the strength of a coal rock mass is reduced, and then the gas permeability of the coal seam is enlarged so as to improve the mining efficiency of the coal seam gas through high-pressure gas injection; the steps are mutually connected, and the steps are mutually cooperated, so that the effect that the former step provides convenience for the subsequent operation or the subsequent step is enhanced is achieved, and the exploitation efficiency of the coalbed methane is greatly improved.
Description
Technical Field
The invention belongs to the technical field of coal exploitation and coalbed methane exploitation, and particularly relates to a coalbed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement.
Background
Coalbed methane in China is characterized by three low and one high: low pressure, low permeability, low saturation and high adsorptivity. At present, two drainage modes are mainly adopted for coal bed gas drainage in China: one is ground pumping drainage; the other is a downhole pump drainage. At present, the main ground drainage method in China is to increase the permeability of a coal seam by vertically drilling a well and then performing a series of permeability increasing measures, such as hydraulic fracturing, gas replacement, low-temperature frost heaving and the like. The hydraulic fracturing can generate a water locking effect when dealing with a coal bed with a complex structure, so that the permeability increasing effect of the coal bed is reduced, and the influence range is reduced; the method of gas displacement and low temperature frost heaving alone is also insufficient to produce the desired effect. In recent years, a mode of combining displacement of the water splitting and slotting aerated body is provided, and the pressure relief and unloading effects can be achieved, but the depth of the seam cannot be ensured, and a certain gap is reserved between the depth and the ideal effect.
Accordingly, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to provide a coal bed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement, which at least solves the problems of non-ideal exploitation effect and the like of the existing coal bed methane exploitation mode.
In order to achieve the above object, the present invention provides the following technical solutions:
the coal bed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement comprises the following steps:
step 1, sealing the drilling hole into a closed space through a limiting fixed hole; specifically, vertically downwards punching holes at the determined positions, downwards punching holes, arranging sealing elements at the upper positions of the holes after the distances capable of arranging the sealing elements are punched, and arranging perforations in the middle of the sealing elements, wherein the perforations are used for a drill bit and a drill rod to pass through so as to realize sealing of the holes;
step 4, taking out the drill bit, and performing steam hole washing to increase the water content in the coal seam;
step 7, after the step is completed, pressurizing displacement is carried out immediately; continuously injecting high-pressure gas into the drill hole to improve the permeability of the coal bed;
and step 8, after the extraction of the coal bed gas reaches the standard, sequentially implementing the steps 4 to 7.
In the coal bed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement, preferably, in step 1, geological exploration is firstly carried out, the drilling position is determined, holes are drilled vertically downwards, radial hole surrounding grooves are drilled on the wall of a drilled hole at a distance of h meters, and sealing elements are manufactured by using organic sealing materials in the hole surrounding grooves.
In the coal bed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement, preferably in step 3, the pressure in the hole is
Based on (a), increasing the air pressure in the hole to +.>
Maintaining the pressure for a period of time;
pressure in the hole is
On the basis of (1), continuing to increase the air pressure in the hole to +.>
And remain the same as the last pressurization process.
In the coal bed methane exploitation method for the water-gas two-phase variable-temperature fracturing displacement, preferably, the pressurizing process in the step 3 is repeated until the air pressure in the hole reaches a preset safety value, pressurizing is stopped, and pressure is released to a preset pressure
。
In the coal bed methane exploitation method for the water-gas two-phase variable-temperature fracturing displacement, preferably, in the step 5, the low-temperature hydraulic gas is liquid nitrogen, the liquid nitrogen solidifies water in the coal bed into ice after being injected into the drill hole, and the liquid nitrogen is gasified in a large amount to increase the air pressure in the drill hole.
In the coal bed methane exploitation method for the water-gas two-phase variable-temperature fracturing displacement, preferably, a pressure detection piece is arranged at a gas outlet hole communicated with the drill hole, and when the pressure is monitored to reach the preset pressure, a valve of the gas outlet hole is opened to release the gas gasified by the liquid nitrogen.
In the coal bed methane exploitation method for the water-gas two-phase variable-temperature fracturing displacement, preferably, in the step 6, the high-temperature inert gas is nitrogen and carbon dioxide.
In the coal bed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement, preferably in step 7, the original pressure is obtained from the drill hole
Increasing the pressure to +.>
After the pressure is maintained for a period of time, the pressure in the drill hole is relieved to +.>
The method comprises the steps of carrying out a first treatment on the surface of the Then from the pressure->
Increasing the pressure to +.>
After the pressure is maintained for a period of time, the pressure in the drill hole is relieved to +.>
The method comprises the steps of carrying out a first treatment on the surface of the Repeating the steps until the drilling pressure reaches a preset safety value, and stopping pressurizing; each pressurizing pressure is larger than the pressure of the last pressurizing.
In the coal bed methane exploitation method for the water-gas two-phase variable-temperature fracturing displacement, preferably, a gas transmission pipeline is arranged in a drill hole;
the downstream of the air compressor is connected with a supercharger, an output port of the supercharger is connected with a gas transmission pipeline, and the gas transmission pipeline penetrates through the sealing element and stretches into the drill hole;
the gas transmission pipeline is also communicated with the vapor transmission pipeline, a valve switch is arranged on the pipeline communicated with the gas transmission pipeline, and the communication point of the vapor transmission pipeline and the vapor transmission pipeline is positioned at the downstream of the supercharger.
In the coal bed methane exploitation method for the water-gas two-phase variable-temperature fracturing displacement, preferably, drilling of the horizontal well is carried out after drilling holes enter a preset coal bed needing permeability improvement;
the middle part of the coal seam is provided with a transverse perforation, a gas-liquid integrated pipeline is arranged in the transverse perforation, and the gas transmission pipeline is communicated with the gas-liquid integrated pipeline.
The beneficial effects are that:
the permeability-increasing principle of the mining method is that the gas pressure in a drill hole is increased firstly, the gas permeability of a coal seam is increased in a small range, then the water content of the coal seam is increased to enable liquid water stored in pores to be changed into solid ice so as to continue permeability increase, then the solid water is liquefied or gasified through high-temperature gas injection, so that the strength of a coal rock mass is reduced, and then the gas permeability of the coal seam is enlarged so as to improve the mining efficiency of the coal seam gas through high-pressure gas injection; the steps are mutually connected, and the steps are mutually cooperated, so that the effect that the former step provides convenience for the subsequent operation or the subsequent step is enhanced is achieved, and the exploitation efficiency of the coalbed methane is greatly improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. Wherein:
FIG. 1 is a schematic flow chart of a mining method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a coal seam gas mining structure in an embodiment of the present invention;
FIG. 3 is a pressure profile of step 2-3 in an embodiment of the present invention;
FIG. 4 is a graph of the boost pressure of step 7 in an embodiment of the present invention;
FIG. 5 is a schematic diagram showing the operation and effect of the mining method according to the embodiment of the present invention.
In the figure: 1. an air compressor; 2. a supercharger; 3. a gas line; 4. a cryogenic liquid transfer conduit; 5. a derrick; 6. a cryogenic liquid storage device; 7. a sealing device; 8. a gas extraction device; 9. a pressure gauge; 10. a valve; 11. a gas-liquid integrated pipeline; 12. a coal seam; 13. a rock formation; 14. perforating; 15. an organic sealing material; 16. a valve switch; 17. a water vapor conveyor.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which are derived by a person skilled in the art based on the embodiments of the invention, fall within the scope of protection of the invention.
In the description of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. refer to the orientation or positional relationship based on that shown in the drawings, merely for convenience of description of the present invention and do not require that the present invention must be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. The terms "coupled" and "connected" as used herein are to be construed broadly and may be, for example, fixedly coupled or detachably coupled; either directly or indirectly through intermediate components, the specific meaning of the terms being understood by those of ordinary skill in the art as the case may be.
The invention will be described in detail below with reference to the drawings in connection with embodiments. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
According to a specific embodiment of the invention, as shown in fig. 1-5, the invention provides a coal bed methane exploitation method for water-gas two-phase temperature-changing fracturing displacement, which comprises the following steps:
step 1, sealing the drilling hole into a closed space through a limiting fixed hole; specifically, vertical downward punching is performed at a well-determined position, then a drilling hole is drilled downwards, after the distance capable of being provided with a sealing element is drilled, the sealing element is arranged at the upper position of the drilling hole, a punching hole is formed in the middle of the sealing element, and a drill bit and a drill rod penetrate through the punching hole so as to seal the drilling hole.
Specifically, geological exploration is first performed, the drilling position is determined, holes are drilled vertically downwards, radial hole surrounding grooves are drilled in the hole wall of the drilled holes at a position h meters away from the hole openings, and organic sealing materials 15 and a reinforcement cage are used in the hole surrounding grooves to manufacture sealing elements.
In the embodiment, a hole is drilled vertically downwards in a coal seam 12 area needing projection increasing, and the value range of h meters is 0.5-1.5 m; the organic sealing material 15 is concrete, a cylindrical hole with the same diameter as the drill rod is reserved in the middle of the poured concrete, and the cylindrical hole is used for the drill rod to pass through, so that the drill hole is sealed at the hole position of the drill hole, and a relatively airtight cavity is formed at the drill bit. A derrick 5 is arranged above the borehole; above and below the coal seam 12 is a formation 13.
The sealing element is made of a steel reinforcement framework and concrete is poured after the template is built. The diameter of the perforation on the sealing element is larger than the maximum diameter of the drill bit and the drill rod, so that the drill bit and the drill rod can pass through the perforation; the sealing rubber ring is arranged in the gap between the perforation of the sealing piece and the drill rod, the sealing of the gap can be realized through the sealing rubber ring, the drilling is convenient to rotate, the cost of the sealing rubber ring is low, and the sealing rubber ring needs to be replaced in time after abrasion occurs.
Installing a gas transmission pipeline in the drill hole; the downstream of the air compressor 1 is connected with a supercharger 2, an output port of the supercharger 2 is connected with a gas transmission pipeline, and the gas transmission pipeline penetrates through the sealing piece and extends into the drill hole; the gas transmission pipeline 3 is also communicated with a vapor conveyor 17, a valve switch 16 is arranged on a pipeline communicated with the vapor conveyor 17, and a communication point between the vapor conveyor 17 and the gas transmission pipeline is positioned at the downstream of the supercharger 2.
In step 3, the pressure in the bore is
Based on (a), increasing the air pressure in the hole to +.>
Maintaining the pressure for a period of time; pressure in the hole is +.>
On the basis of (1), continuing to increase the air pressure in the hole to +.>
And remain the same as the last pressurization process.
In this embodiment, the values of each pressurization are the same, and each pressurization value is 1 to 2 atmospheres greater than the previous pressurization value; the dwell time is the same; in this step, the increased air pressure forms a powerful shock wave, which is transmitted into the coal seam 12, and impacts and shakes the coal seam 12, thereby increasing the fracture property of the coal seam 12; and the pressure is maintained for a period of time after each pressurization, so that the crack development of the coal seam 12 in the anti-reflection area is more sufficient.
When the drilled holes enter a preset coal seam 12 needing permeability improvement, drilling a horizontal well, namely, drilling a transverse perforation in the middle of the coal seam 12, wherein the transverse perforation extends along the trend of the coal seam 12; and the transverse drilling holes are communicated with the air outlet holes, and the drilling holes are sealed after the drill rod and the drill bit are withdrawn and pressed on the perforation holes of the sealing piece through the precast concrete cover.
The transverse perforation in the application communicates drilling and venthole simultaneously, has arranged gas-liquid integration pipeline 11 in the transverse perforation, and gas transmission pipeline and gas-liquid integration pipeline 11 intercommunication to be convenient for more even the carrying of gas that transmits in the gas transmission pipeline in the coal seam 12.
Repeating the pressurizing process in the step 3 until the air pressure in the hole reaches a preset safety value, stopping pressurizing, and releasing the pressure to a preset pressure
. The air pressure is increased step by step, and the pressure is maintained, so that the influence range of the high air pressure is transmitted farther, the fracture property of the whole coal seam is better, and a better foundation is provided for further improving the extraction efficiency.
Step 4, taking out the drill bit, and performing steam hole washing to increase the water content in the coal seam 12; conveying water vapor into the drill holes at the lower part of the sealing element so as to store liquid water in the pores of the coal seam 12 in the anti-reflection area, improve the water content of the coal seam 12 and lay a cushion for the next anti-reflection step; in the embodiment, the gas pipeline 3 is also communicated with a steam conveyer 17, a valve switch 16 is arranged on the pipeline communicated with the gas pipeline and the steam conveyer, and the steam conveyer is provided with a valve switch on the pipeline communicated with the water conveyerThe connection point of the engine 17 and the gas line is located downstream of the supercharger 2. At the time of pressure release to a predetermined pressure
After that, the valve switch 16 is opened, the steam conveyer 17 is started, and steam is conveyed into the borehole through the gas pipeline 3.
In step 5, the low temperature hydraulic gas is liquid nitrogen, which solidifies water in the coal seam 12 into ice after being injected into the borehole, and the liquid nitrogen is largely gasified to increase the gas pressure in the borehole.
In this embodiment, the water content in the pores of the coal seam 12 becomes greater because of the steam hole washing step; the temperature of the liquid nitrogen is extremely low, and after the liquid nitrogen is injected, the coal body and the water are changed into organic whole; the residual water in the cracks in and around the drill holes is solidified into ice due to the extremely low temperature of the liquid nitrogen, and the physical phenomenon of volume expansion exists in the process of solidifying the water into ice, so that the surrounding coal bed 12 bodies can be extruded in the process, the crushing degree of the coal rock bodies is increased, and the air permeability of the coal bed 12 bodies is further increased; the low temperature effect of the liquid nitrogen can increase more small cracks, and the cracks can become channels for outputting the coal bed gas in the coal bed gas exploitation process, so that the coal bed gas exploitation efficiency is improved; meanwhile, a large amount of liquid nitrogen can be gasified in a short time, the air pressure in the drilling hole can be rapidly increased, the crack density of the coal body can be increased to a certain extent, the air permeability is increased, and gasified liquid nitrogen can be discharged through the air outlet hole. In other words, in the mining method, the steam hole washing and the injected liquid nitrogen have the mutually cooperative function, so that the crack sealing and the air permeability of the coal body are greatly improved.
And a pressure detection part is arranged at the air outlet hole communicated with the drilling hole, and when the pressure is detected to reach the preset pressure, the valve 10 of the air outlet hole is opened, and the gas gasified by the liquid nitrogen is released. In this embodiment, the pressure monitoring piece is a pressure gauge 9, a sealing device 7 is disposed at the position of the orifice of the air outlet, the monitoring end of the pressure gauge 9 penetrates through the sealing device 7 and stretches into the space to be detected, and the dial plate of the pressure gauge 9 stretches out of the sealing device 7, so that the air pressure value in the space to be detected can be read. The gas extraction device 8 is further arranged at a position close to the outlet hole, and the gas extraction device 8 is connected with an extraction pipeline which penetrates through the sealing device 7 and stretches into the air outlet hole.
Step 7, after the step is completed, pressurizing displacement is carried out immediately; continuously injecting high-pressure gas into the drill hole to improve the permeability of the coal seam 12; in particular, as in step 3, from the original pressure of the borehole
Increasing the pressure to +.>
After the pressure is maintained for a period of time, the pressure in the drill hole is relieved to +.>
The method comprises the steps of carrying out a first treatment on the surface of the Then from the pressure->
Increasing the pressure to +.>
After the pressure is maintained for a period of time, the pressure in the drill hole is relieved to +.>
The method comprises the steps of carrying out a first treatment on the surface of the Repeating the steps until the drilling pressure reaches a preset safety value, and stopping pressurizing; each pressurizing pressure is larger than the pressure of the last pressurizing.
In the present embodiment, the subsequent pressurizing pressure is greater than the last pressurizing pressure, i.e
The pressure detection part is used for detecting whether the pressure in the drill hole reaches a preset safety value or not. Step 7 is to continuously increase the development degree of the fissures of the coal seam 12, and continuously increase the air pressure in the drill holes, because the strength of the coal seam 12 is reduced in the previous step, the injected high-pressure air can expand in the stratum to change the pressure conduction characteristic, and the permeability of the coal seam 12 is rapidly improved by continuously pressurizing and impacting the coal seam 12, so that the stratum energy and the air diffusion rate of the coal seam 12 are increased, the coal seam air exploitation efficiency is improved, and the yield and the recovery ratio are further improved.
And step 8, after the extraction of the coal bed gas reaches the standard, sequentially implementing the steps 4 to 7.
In summary, in the technical scheme of the coal bed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement provided by the invention, the exploitation method combining limiting fixed holes, air pressure displacement, steam hole washing, low-temperature fracturing, high Wen Quti and pressurizing displacement is implemented in the same drill hole in steps, the permeability increasing effect of the coal bed can be increased in each step of the exploitation method, and the drill hole forms a relatively airtight space due to the effect of the retention limiting holes, so that liquid nitrogen is gasified rapidly, the air pressure in the drill hole can be increased rapidly, and the fracture density of the coal bed body is further increased continuously, so that the air permeability of the coal bed body is increased; the gas pressure displacement can take away the coal bed gas in the coal bed and can also increase the crack density of the coal bed, wherein the step of washing holes by the steam can increase the water content of the coal bed, liquid water stored in the holes of the coal bed can be quickly frozen under the action of liquid nitrogen, the volume increase of the water in the frozen process can press surrounding rock mass, further, the continuous increase of the cracks of the coal bed around a drill hole can be realized, the gas permeability of the coal bed is increased, the liquid nitrogen is injected from the drill hole, then high-temperature pressure injection is carried out, high-temperature gas (such as 80 ℃ high-temperature inert gas) is injected from the drill hole, the solid ice stored in the coal bed in the process can be changed into liquid state again or evaporated into gas state directly in the process, the gas pressure of the drill hole is increased, the gas permeability of the drill hole is further increased, the analysis balance of the coal bed gas can be damaged, the coal bed gas yield is increased, the gas yield of the coal bed is increased, the gas mining efficiency of the coal bed is better improved in order to continue to expand the gas permeability of the coal bed, the original germination is further, the gas is further increased, the gas permeability of the coal bed is improved, the coal bed is finally, the high-pressure gas is finally carried out, the gas is increased, the crack of the coal bed gas in the process is opened, the coal bed is the coal seam is the channel, the crack is opened, and the gas is increased.
The permeability-increasing principle of the mining method is that the gas pressure in a drill hole is increased firstly, the gas permeability of a coal seam is increased in a small range, then the water content of the coal seam is increased to enable liquid water stored in pores to be changed into solid ice so as to continue permeability increase, then the solid water is liquefied or gasified through high-temperature gas injection, so that the strength of a coal rock mass is reduced, and then the gas permeability of the coal seam is enlarged so as to improve the mining efficiency of the coal seam gas through high-pressure gas injection; the steps are mutually connected, and the steps are mutually cooperated, so that the effect that the former step provides convenience for the subsequent operation or the subsequent step is enhanced is achieved, and the anti-reflection effect of the coal seam body is superimposed more scientifically, greenly and reasonably in general.
It is to be understood that the above description is exemplary only and that the embodiments of the present application are not limited thereto.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Claims (6)
1. The coal bed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement is characterized by comprising the following steps of:
step 1, sealing the drilling hole into a closed space through a limiting fixed hole; specifically, vertically downwards punching holes at the determined positions, downwards punching holes, arranging sealing elements at the upper positions of the holes after the distances capable of arranging the sealing elements are punched, and arranging perforations in the middle of the sealing elements, wherein the perforations are used for a drill bit and a drill rod to pass through so as to realize sealing of the holes;
step 2, then pressure maintaining drilling is carried out; specifically, drilling is continued until the middle part of the preset coal seam is reached; during this process, high-pressure air is punched into the bore hole in the lower part of the sealing member, so that the air pressure in the bore hole is always kept at a safe constant value
；
Step 3, after the drill bit reaches the preset middle position of the coal seam, performing pneumatic displacement, and continuing drilling until the drill bit reaches the bottom of the coal seam; at this time from the constant value of the air pressure
Firstly, gradually increasing the internal air pressure of the drill hole;
step 4, taking out the drill bit, and performing steam hole washing to increase the water content in the coal seam;
step 5, low-temperature fracturing is carried out, low-temperature liquid gas is introduced into the drill hole, and water in the coal bed is solidified into ice at low temperature, so that more small cracks appear in the coal bed;
step 6, after the low-temperature liquid gas is gasified and discharged in the previous step, then high-temperature pressure injection is carried out, high-temperature inert gas is injected into the drill hole, and the high-temperature inert gas thaws the frozen coal body to change the solid ice formed in the previous step into a gaseous state;
step 7, after the step is completed, pressurizing displacement is carried out immediately; continuously injecting high-pressure gas into the drill hole to improve the permeability of the coal bed;
step 8, after the extraction of the coal bed gas reaches the standard, sequentially implementing the steps 4 to 7;
in step 3, the pressure in the bore is
Based on (a), increasing the air pressure in the hole to +.>
Maintaining the pressure for a period of time;
pressure in the hole is
On the basis of (1), continuing to increase the air pressure in the hole to +.>
And remain the same as the last pressurization process;
repeating the pressurizing process in the step 3 until the air pressure in the hole reaches a preset safety value, stopping pressurizing, and releasing the pressure to a preset pressure
；
In step 7, the original pressure is obtained from the borehole
Increasing the pressure to +.>
After the pressure is maintained for a period of time, the pressure in the drill hole is relieved to +.>
The method comprises the steps of carrying out a first treatment on the surface of the Then from the pressure->
Increasing the pressure to +.>
After the pressure is maintained for a period of time, the pressure in the drill hole is relieved to +.>
The method comprises the steps of carrying out a first treatment on the surface of the Repeating the steps until the drilling pressure reaches a preset safety value, and stopping pressurizing; each pressurizing pressure is larger than the pressure of the last pressurizing.
2. The method of coal bed methane recovery by two-phase alternating temperature fracturing displacement of water and gas according to claim 1, wherein in step 1, geological exploration is first carried out, drilling positions are determined, holes are drilled vertically downwards, radial hole surrounding grooves are drilled in the wall of the drilled holes at a distance of h meters from the holes, and sealing elements are made of organic sealing materials in the hole surrounding grooves.
3. The method of coal bed methane recovery by water-gas two-phase temperature swing fracturing displacement according to claim 1, wherein in step 5, the low-temperature hydraulic gas is liquid nitrogen, the liquid nitrogen solidifies water in the coal bed into ice after being injected into the borehole, and the liquid nitrogen is largely gasified to increase the gas pressure in the borehole.
4. The coalbed methane exploitation method for water-gas two-phase variable-temperature fracturing displacement according to claim 3, wherein a pressure detection piece is arranged at an air outlet hole communicated with the drill hole, and when the pressure is detected to reach a preset pressure, a valve of the air outlet hole is opened to release the gas gasified by the liquid nitrogen.
5. The coalbed methane exploitation method for water-gas two-phase variable temperature fracturing displacement according to any one of claims 1-4, wherein a gas transmission pipeline is arranged in a drill hole;
the downstream of the air compressor is connected with a supercharger, an output port of the supercharger is connected with a gas transmission pipeline, and the gas transmission pipeline penetrates through the sealing element and stretches into the drill hole;
the gas transmission pipeline is also communicated with the vapor transmission pipeline, a valve switch is arranged on the pipeline communicated with the gas transmission pipeline, and the communication point of the vapor transmission pipeline and the vapor transmission pipeline is positioned at the downstream of the supercharger.
6. The method for exploiting the coalbed methane by the water-gas two-phase variable temperature fracturing displacement according to claim 5, wherein the drilling of the horizontal well is performed after a drill hole enters a preset coalbed needing permeability improvement;
the middle part of the coal seam is provided with a transverse perforation, a gas-liquid integrated pipeline is arranged in the transverse perforation, and the gas transmission pipeline is communicated with the gas-liquid integrated pipeline.
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| CN107091798B (en) * | 2017-04-21 | 2019-07-09 | 中国矿业大学 | Simulator is transformed in anxious formula hot and cold alternation coalbed methane reservoir |
| CN112412420A (en) * | 2020-11-05 | 2021-02-26 | 河南理工大学 | Hydraulic cavitation, freezing fracturing and heat injection stimulation synergistic anti-reflection pumping-promoting method |
| CN112412415B (en) * | 2020-11-05 | 2022-11-04 | 河南理工大学 | Hydraulic punching, freezing fracturing and heat injection stimulation synergistic permeability-increasing pumping-promoting method |
| CN113137268A (en) * | 2021-03-17 | 2021-07-20 | 徐州工程学院 | Method for increasing coal permeability through high-low temperature cyclic impact after hydraulic slotting |
| CN114183114B (en) * | 2021-12-07 | 2022-11-08 | 中国矿业大学 | Hydraulic punching and cave-making cooperative steam injection enhanced gas extraction method |
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