CN111520182A - Electric pulse fracturing and gas injection displacement synergistic regional gas extraction method - Google Patents
Electric pulse fracturing and gas injection displacement synergistic regional gas extraction method Download PDFInfo
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- CN111520182A CN111520182A CN202010344172.6A CN202010344172A CN111520182A CN 111520182 A CN111520182 A CN 111520182A CN 202010344172 A CN202010344172 A CN 202010344172A CN 111520182 A CN111520182 A CN 111520182A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F7/00—Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/164—Injecting CO2 or carbonated water
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
- E21B43/168—Injecting a gaseous medium
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
Abstract
The invention discloses a regional gas extraction method with electric pulse fracturing and gas injection displacement cooperated. The high-voltage electric pulse device is used for carrying out repeated discharge on the coal bed, and a space network-shaped crack structure is formed in the coal bed, so that free gas is released. After the free gas is extracted, gas with a gas displacement effect is injected into the coal bed by using a gas injection system, the gas adsorbed in the coal pores is further desorbed by using the displaceable gas, and then the desorbed gas is further extracted, so that the gas in the coal bed is fully extracted, and the requirements of underground construction are met.
Description
Technical Field
The invention relates to a regional gas extraction method with electric pulse fracturing and gas injection displacement cooperated, belongs to the field of fracturing permeability improvement and gas extraction of regional coal beds in coal mines, and is particularly suitable for operation of gas coal beds with high adsorption, low permeability and difficult desorption.
Background
In recent years, with the deepening of coal mining depth, the problems of high gas, low permeability, difficult desorption and the like in the coal mining process are increasingly highlighted, and the key for solving the problems lies in gas extraction. The coal seam permeability increasing technology is an important means for solving the problem of gas extraction of a low-permeability coal seam. Related researches show that extracted gas mainly comprises a free state and an adsorption state, and existing permeability-increasing technologies such as hydraulic fracturing, hydraulic slotting, electric pulse fracturing and the like can only extract the gas in the free state, and the gas in the adsorption state cannot be extracted normally. Therefore, a simple, efficient, safe and quick coal seam gas extraction method is urgently needed.
Disclosure of Invention
The invention aims to provide a regional gas extraction method with cooperation of electric pulse fracturing and gas injection displacement, which is simpler and more efficient and has more sufficient extraction effect, aiming at the increasingly prominent problems of high gas, low gas permeability, difficult desorption and the like in the coal mining process.
In order to achieve the purpose, the invention provides a regional gas extraction method with the cooperation of electric pulse fracturing and gas injection displacement, which comprises the following steps:
s1, drilling cross-layer drill holes in the coal seam of the area to be treated by gas in a conventional drilling mode, wherein the drill holes are alternately arranged according to positive electrode drill holes and negative electrode drill holes, and the top ends of the cross-layer drill holes penetrate through the top plate of the coal seam by 2-3 m;
s2, after drilling construction is completed, sending a gas injection pipe to the bottom of a negative electrode drill hole, sending an exhaust pipe to the bottom of a positive electrode drill hole adjacent to the negative electrode drill hole, sending a negative electrode to the bottom of the negative electrode drill hole by using an insulating high-pressure rubber pipe II, sending a positive electrode to the bottom of the positive electrode drill hole by using an insulating high-pressure rubber pipe I, ensuring that the negative electrode and the positive electrode are in close contact with a coal bed, electrically connecting the negative electrode and the positive electrode with a high-pressure charging power supply respectively, sealing the negative electrode drill hole and the positive electrode drill hole after installation, connecting the gas injection pipe extending out of the exposed end of the orifice with a gas injection system, connecting the exhaust pipe extending out of the exposed end of;
s3, after the electrode connection is completed, charging the preset voltage of 500-1500kV into the high-voltage charging power supply, opening the high-voltage discharge switch to discharge the coal seam, and repeating the discharge for 200-300 times;
s4, after the discharge is repeated at the same place of the coal seam for 200-300 times, the positive electrode and the negative electrode are respectively moved for 2-3m towards the drilling direction, then the step S3 is repeated, the discharge is stopped until the positive electrode and the negative electrode are 2-3m away from the drilling, and the high-voltage discharge switch is turned off;
s5, opening an extraction throttle valve and an extraction system, and extracting free and partially desorbed gas in the coal seam after electric pulse fracturing;
s6, when the gas extraction concentration is reduced to 30% -40% of the normal range, closing the extraction throttle valve and the extraction system, then opening the gas injection control valve and the gas injection system, injecting displacement gas with certain pressure into the coal seam, driving and replacing the gas which cannot be normally desorbed in the pores of the coal seam, and maintaining the gas injection pressure constant for a period of time;
s7, closing the gas injection control valve and the gas injection system, opening the extraction throttle valve, the extraction system and the gas separation device, allowing the separated gas to flow into the ground through an extraction pipeline for storage, and allowing the separated displacement gas to be stored underground for reuse;
and S8, repeating the operation steps S3, S4, S5, S6 and S7 to achieve the optimal gas extraction effect.
Preferably, the displacement gas is carbon dioxide or dry air.
Preferably, the distance between the orifices of the positive electrode drill hole and the negative electrode drill hole is 3-8 m.
Preferably, the displacement time is 10-60 days, and the pressure range of the displacement gas is 1-5 MPa.
Further, a gas concentration detection device is further arranged on the gas extraction pipeline and used for detecting the gas extraction concentration in real time.
Further, a pressure gauge is arranged on the gas injection pipeline and used for displaying the pressure of gas injection.
Has the advantages that: the regional gas extraction method with the synergy of electric pulse fracturing and gas injection displacement can effectively overcome the limitation of the traditional single permeability-increasing mode and single gas injection displacement extraction mode, and the desorption of residual gas and adsorbed gas is fully promoted by using the gas injection displacement method after the electric pulse permeability-increasing is carried out on the coal seam, so that the gas extraction efficiency is improved. According to the invention, the mutually-communicated fracture network is generated in the coal bed by the technology of directly repeating discharge in the coal bed through high-voltage electric pulses, so that on one hand, free gas in the coal bed can be directly released, and on the other hand, a better channel can be provided for later-stage injected displacement gas. After the free gas is extracted, the displacing gas is injected into the coal bed, the gas which is difficult to desorb in the coal bed is driven and replaced, and the desorption of the gas is further promoted, so that the gas extraction in the coal bed is more sufficient and thorough, the safety of underground construction is improved, and the method has wide practical value in the technical field.
Drawings
FIG. 1 is a schematic diagram of a regional gas extraction method with electric pulse fracturing and gas injection displacement in coordination according to the invention;
FIG. 2 is a schematic view of the cross-drilled hole arrangement of FIG. 1;
in the figure: the method comprises the following steps of 1-a high-voltage charging power supply, 2-a high-voltage discharging switch, 3-a first insulating high-voltage rubber tube, 4-a positive electrode, 5-a negative electrode, 6-a negative electrode drill hole, 7-a positive electrode drill hole, 8-a first hole packer, 9-a second hole packer, 10-an air injection control valve, 11-an air injection system, 12-a coal bed, 13-an air injection pipe, 14-a second insulating high-voltage rubber tube, 15-an exhaust pipe, 16-a first sealing plug, 17-a second sealing plug, 18-an extraction throttle valve, 19-an extraction system, 20-a gas separation system, 21-a working face air return roadway, 22-a working face air inlet roadway, 23-a working face hole, 24-a lead, 25-a gas concentration detection device and.
Detailed Description
An embodiment of the present invention is further described below with reference to the accompanying drawings:
as shown in fig. 1, the method for extracting the regional gas by the cooperation of electric pulse fracturing and gas injection displacement comprises the following specific steps:
s1, as shown in figure 2, constructing a row of through-layer drill holes from the working face air return roadway 21 and the working face air inlet roadway 22 to the working face cutting holes 23 according to a conventional drilling mode, wherein the drill holes are arranged according to an alternating mode of the positive electrode drill holes 7 and the negative electrode drill holes 6; the top end of the cross-layer drill hole penetrates through the coal seam roof by 2.5m, and the distance between the orifices of the positive electrode drill hole 7 and the negative electrode drill hole 6 is 3 m;
s2, after drilling construction is completed, sending the gas injection pipe 13 to the bottom of the negative electrode drill hole 6, sending the exhaust pipe 15 to the bottom of the positive electrode drill hole 7 adjacent to the negative electrode drill hole 6, sending the negative electrode 5 to the negative electrode drill hole 6 by using the second insulating high-pressure rubber pipe 14, sending the positive electrode 4 to the bottom of the positive electrode drill hole 7 by using the first insulating high-pressure rubber pipe 3, ensuring that the negative electrode 5 and the positive electrode 4 are both in close contact with the coal seam 12, and connecting the negative electrode 5 and the positive electrode 4 with the high-voltage charging power supply 1 through the; after the installation is finished, a first hole packer 8 is used for sealing the negative electrode drill hole 6, a second hole packer 9 is used for sealing the positive electrode drill hole 7, a gas injection pipe 13 extending out of the exposed end of the negative electrode drill hole 6 is connected with a gas injection system 11, a gas injection control valve 10 and a pressure gauge 26 are sequentially arranged on the gas injection pipe, a gas exhaust pipe 15 extending out of the exposed end of the positive electrode drill hole 7 is connected with a gas extraction system 19, an extraction throttle valve 18 and a gas concentration detection device 25 are sequentially arranged on the gas extraction pipe, a gas separation device 20 is further connected to the tail end of the gas extraction system 19, a first sealing plug 16 is used for sealing a second insulating high-pressure rubber pipe 14, and a second sealing plug 17 is used for sealing a;
s3, after the electrode connection is completed, charging the preset voltage of 500-1500kV into the high-voltage charging power supply 1, wherein the voltage is set to be 1000kV according to the field condition, opening the high-voltage discharge switch 2 to discharge the coal seam 12, and repeating the discharge for 200-300 times;
s4, after the discharge is repeated 200-300 times to the same place of the coal seam 12, the positive electrode 4 and the negative electrode 5 are respectively moved 2-3m towards the respective drilling direction, then the step S3 is repeated until the distance between the positive electrode 4 and the negative electrode 5 and the drilling reaches 2-3m, the discharge is stopped, and the high-voltage discharge switch 2 is closed;
s5, after the discharge is stopped, starting the extraction throttle valve 18 and the extraction system 19, and extracting the free and partially desorbed gas in the coal seam after the electric pulse fracturing;
s6, when the gas concentration detection device 25 detects that the gas extraction concentration is reduced to 30% -40% of the normal range, closing the extraction throttle valve 18 and the extraction system 19, then opening the gas injection control valve 10 and the gas injection system 11, and injecting displacement gas with the pressure of 1-5MPa into the coal seam 12, wherein carbon dioxide gas with the pressure of 3MPa is injected in the embodiment to drive and replace gas which cannot be normally desorbed in the pores of the coal seam, and keeping the gas injection pressure constant for 10-60 days;
s7, closing the gas injection control valve 10 and the gas injection system 11, opening the extraction throttle valve 18, the extraction system 19 and the gas separation device 20, allowing the separated gas to flow into the ground through an extraction pipeline for storage, and allowing the separated carbon dioxide gas to be stored underground for reuse;
and S8, repeating the operation steps S3, S4, S5, S6 and S7 to achieve the optimal gas extraction effect.
According to the invention, through the technology that electric pulses directly discharge in the coal bed, the inside of the coal body between the positive electrode drill hole and the negative electrode drill hole forms a mutually communicated fracture network structure, on one hand, free gas can be released, on the other hand, a good gas extraction channel is formed, and then, gas which is difficult to desorb in the coal bed is driven and replaced by using displacing gas, so that the gas is more fully desorbed, and the requirements of underground construction are met.
Claims (6)
1. An electric pulse fracturing and gas injection displacement collaborative regional gas extraction method is characterized by comprising the following steps:
s1, drilling cross-layer drill holes in the coal seam (12) of the area to be treated by gas in a conventional drilling mode, wherein the drill holes are arranged in an alternating mode of a positive electrode drill hole (7) and a negative electrode drill hole (6), and the top ends of the cross-layer drill holes penetrate through the top plate of the coal seam (12) by 2-3 m;
s2, after drilling construction is completed, sending the gas injection pipe (13) to the bottom of a negative electrode drill hole (6), sending the exhaust pipe (15) to the bottom of a positive electrode drill hole (7) adjacent to the negative electrode drill hole (6), sending a negative electrode (5) to the bottom of the negative electrode drill hole (6) by using an insulating high-pressure rubber pipe II (14), sending a positive electrode (4) to the bottom of the positive electrode drill hole (7) by using an insulating high-pressure rubber pipe I (3), ensuring that the negative electrode (5) and the positive electrode (4) are in close contact with a coal bed (12), electrically connecting the negative electrode (5) and the positive electrode (4) with a high-pressure charging power supply (1) respectively, sealing the negative electrode drill hole (6) and the positive electrode drill hole (7) after installation, connecting the gas injection pipe (13) extending out of an exposed end of an orifice with a gas injection system (11), and connecting the exhaust pipe (15) extending, simultaneously sealing the second insulating high-pressure rubber pipe (14) and the first insulating high-pressure rubber pipe (3);
s3, after the electrode connection is finished, charging the preset voltage of 500-1500kV into the high-voltage charging power supply (1), and opening the high-voltage discharge switch (2) to discharge the coal seam (12), wherein the discharge is repeated for 200-300 times;
s4, after the discharge is repeated 200-300 times to the same place of the coal seam (12), the positive electrode (4) and the negative electrode (5) are respectively moved 2-3m towards the drilling direction, then the step S3 is repeated, the discharge is stopped until the positive electrode (4) and the negative electrode (5) are 2-3m away from the drilling, and the high-voltage discharge switch (2) is closed;
s5, opening an extraction throttle valve (18) and an extraction system (19) to extract free and partially desorbed gas in the coal seam after electric pulse fracturing;
s6, when the gas extraction concentration is reduced to 30% -40% of the normal range, closing the extraction throttle valve (18) and the extraction system (19), then opening the gas injection control valve (10) and the gas injection system (11), injecting displacement gas with certain pressure into the coal seam (12), driving and replacing gas which cannot be normally desorbed in the pores of the coal seam, and maintaining the gas injection pressure constant for a period of time;
s7, closing the gas injection control valve (10) and the gas injection system (11), opening the extraction throttle valve (18), the extraction system (19) and the gas separation device (20), allowing the separated gas to flow into the ground through an extraction pipeline for storage, and allowing the separated displacement gas to be stored underground for reuse;
and S8, repeating the operation steps S3, S4, S5, S6 and S7 to achieve the optimal gas extraction effect.
2. The regional gas extraction method based on the cooperation of electric pulse fracturing and gas injection displacement according to claim 1, wherein the displacement gas is carbon dioxide or dry air.
3. The regional gas extraction method combining electric pulse fracturing and gas injection displacement according to claim 1, wherein the distance between the orifices of the positive electrode drill hole (7) and the negative electrode drill hole (6) is 3-8 m.
4. The regional gas extraction method based on the cooperation of electric pulse fracturing and gas injection displacement according to claim 1, wherein the displacement time is 10-60 days, and the pressure range of the displacement gas is 1-5 MPa.
5. The regional gas extraction method based on the cooperation of electric pulse fracturing and gas injection displacement according to claim 1, characterized in that a gas concentration detection device (25) is further arranged on the extraction pipeline.
6. The regional gas extraction method based on the cooperation of electric pulse fracturing and gas injection displacement according to claim 1, characterized in that a pressure gauge (26) is further arranged on the gas injection pipeline.
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| CN202010344172.6A CN111520182A (en) | 2020-04-27 | 2020-04-27 | Electric pulse fracturing and gas injection displacement synergistic regional gas extraction method |
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| CN202010344172.6A CN111520182A (en) | 2020-04-27 | 2020-04-27 | Electric pulse fracturing and gas injection displacement synergistic regional gas extraction method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112459722A (en) * | 2020-11-23 | 2021-03-09 | 中国矿业大学 | Punching device and method based on cooperation of nano-fluid-based electrohydraulic breakdown and infrared thermal radiation |
| CN115450594A (en) * | 2022-09-22 | 2022-12-09 | 中国矿业大学 | Gas injection displacement effect detection method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2579245C (en) * | 2006-02-22 | 2011-09-27 | Schlumberger Canada Limited | Method of intensification of natural gas production from coal beds |
| CN106337672A (en) * | 2016-10-25 | 2017-01-18 | 中国矿业大学 | Method for extracting coal bed gas from circulating pulse type low temperature freeze-thawed anti-reflection coal |
| CN107630717A (en) * | 2017-09-18 | 2018-01-26 | 中国矿业大学 | The coal seam anti-reflection method that a kind of electric pulse mutually cooperates with coal-bed flooding |
| CN109162755A (en) * | 2018-09-11 | 2019-01-08 | 中国矿业大学 | A kind of coal uncovering method that electric pulse is combined with grouting and reinforcing |
| CN109252861A (en) * | 2018-09-11 | 2019-01-22 | 中国矿业大学 | A kind of electric pulse auxiliary liquid nitrogen freezing formula coal uncovering method |
| CN110792468A (en) * | 2019-09-06 | 2020-02-14 | 西安科技大学 | Underground coal mine cyclic pulse gas injection displacement gas extraction system |
-
2020
- 2020-04-27 CN CN202010344172.6A patent/CN111520182A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2579245C (en) * | 2006-02-22 | 2011-09-27 | Schlumberger Canada Limited | Method of intensification of natural gas production from coal beds |
| CN106337672A (en) * | 2016-10-25 | 2017-01-18 | 中国矿业大学 | Method for extracting coal bed gas from circulating pulse type low temperature freeze-thawed anti-reflection coal |
| CN107630717A (en) * | 2017-09-18 | 2018-01-26 | 中国矿业大学 | The coal seam anti-reflection method that a kind of electric pulse mutually cooperates with coal-bed flooding |
| CN109162755A (en) * | 2018-09-11 | 2019-01-08 | 中国矿业大学 | A kind of coal uncovering method that electric pulse is combined with grouting and reinforcing |
| CN109252861A (en) * | 2018-09-11 | 2019-01-22 | 中国矿业大学 | A kind of electric pulse auxiliary liquid nitrogen freezing formula coal uncovering method |
| CN110792468A (en) * | 2019-09-06 | 2020-02-14 | 西安科技大学 | Underground coal mine cyclic pulse gas injection displacement gas extraction system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112459722A (en) * | 2020-11-23 | 2021-03-09 | 中国矿业大学 | Punching device and method based on cooperation of nano-fluid-based electrohydraulic breakdown and infrared thermal radiation |
| CN115450594A (en) * | 2022-09-22 | 2022-12-09 | 中国矿业大学 | Gas injection displacement effect detection method |
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