CN109854221B - Underground cooling and heating alternate working cycle fracturing and permeability increasing coal seam system and extraction method - Google Patents
Underground cooling and heating alternate working cycle fracturing and permeability increasing coal seam system and extraction method Download PDFInfo
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- CN109854221B CN109854221B CN201910174682.0A CN201910174682A CN109854221B CN 109854221 B CN109854221 B CN 109854221B CN 201910174682 A CN201910174682 A CN 201910174682A CN 109854221 B CN109854221 B CN 109854221B
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 101
- 239000003245 coal Substances 0.000 title claims abstract description 90
- 238000001816 cooling Methods 0.000 title claims abstract description 38
- 238000000605 extraction Methods 0.000 title claims abstract description 18
- 230000035699 permeability Effects 0.000 title claims description 13
- 230000001965 increasing effect Effects 0.000 title claims description 9
- 238000002347 injection Methods 0.000 claims abstract description 71
- 239000007924 injection Substances 0.000 claims abstract description 71
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 64
- 238000007789 sealing Methods 0.000 claims abstract description 35
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 32
- 239000007789 gas Substances 0.000 claims abstract description 27
- 239000007788 liquid Substances 0.000 claims abstract description 20
- 238000009413 insulation Methods 0.000 claims abstract description 14
- 230000000694 effects Effects 0.000 claims abstract description 10
- 238000005553 drilling Methods 0.000 claims description 50
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 6
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 239000011148 porous material Substances 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- 230000035939 shock Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000005422 blasting Methods 0.000 description 2
- 238000007710 freezing Methods 0.000 description 2
- 230000008014 freezing Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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Abstract
The invention discloses a downhole cooling and heating alternate working cycle fracturing permeability-increasing coal bed system and a method, which are applicable to the technical field of coal bed gas extraction. Alternately arranging cold injection drill holes and heating drill holes on a coal seam, paving a heat insulation plate on the surface of the coal seam, paving a heating cable in the heating drill holes, respectively installing sealing covers at the hole openings of the cold injection drill holes and the heating drill holes, continuously injecting low-temperature liquid nitrogen into the cold injection drill holes until the inside of the whole drill holes is filled, and screwing a valve to be dead after the injection is stopped; heating the coal bed to quickly gasify liquid nitrogen in the cold injection drill holes and discharge nitrogen in the cold injection drill holes; and after the operations from the fourth step to the sixth step are repeated for 5-7 times, taking out the sealing covers and the heating cables of all the drilled holes, and extracting the coal bed gas after hole sealing. The method has simple steps and good extraction effect.
Description
Technical Field
The invention relates to an anti-reflection coal seam system and an extraction method, in particular to an anti-reflection coal seam system and an anti-reflection coal seam method which are used in the technical field of coal seam gas extraction and are cracked under the condition of underground injection cooling and heating alternating working cycle.
Background
Most of Chinese coal seams are low-permeability high-gas coal seams, in order to ensure the safe production of coal mines, the method of ground drilling or underground drilling is usually used for pre-pumping coal bed gas (gas), but because the coal bed gas has low permeability and the direct pre-pumping effect is not ideal, a plurality of physical and chemical methods of fracturing and permeability-increasing coal seams are used for enhancing the extraction of the coal bed gas, for example: deep hole blasting, hydraulic fracturing, hydraulic punching, hydrochloric acid chemical methods and the like, which improve the extraction rate of the coal bed gas to different degrees, but have the defects at the same time. The deep hole blasting method needs reasonable explosive installation, is complex to operate and has certain danger; the hydraulic fracture method requires cutting through the drill holes, and the operation difficulty is high; the hydraulic punching method wastes a large amount of water resources, and the produced sewage can pollute underground water due to improper treatment; the chemical reagent used by the hydrochloric acid chemical method can seriously affect the quality of underground water and threaten the ecological environment and the physical health of local residents.
In recent years, a method for alternately injecting a cold source and a heat source into a plurality of single drill holes to fracture the anti-reflection coal seam is also generated, but due to the limitation of the diameter of the drill holes, the installation and the operation of the device are more complicated and complicated, the invention provides the method for fracturing the coal seam by the cooperation of the cold holes and the hot holes, the anti-reflection effect is obvious, and the method has the advantages of simplicity in operation and lower cost.
Disclosure of Invention
The invention aims to provide a downhole cooling and heating alternate working cycle fracturing permeability-increasing coal bed system and a method, which are used for solving the problems in the prior art and have the advantages of remarkable coal bed gas extraction effect, simplicity in operation and lower cost.
In order to achieve the purpose, the underground injection cooling and heating alternate working cycle cracking permeability-increasing coal bed system comprises a plurality of injection cooling drill holes and a plurality of heating drill holes, wherein the plurality of injection cooling drill holes and the plurality of heating drill holes are alternately arranged on a coal bed; performing injection cooling drilling and heating drilling;
the cold injection drill hole comprises a sealing cover for plugging the hole of the drill hole, the sealing cover is respectively provided with a manual pressure relief valve and a safety valve which are communicated with the inside of the drill hole, and a pressure sensor and a liquid nitrogen injection pipeline which are connected with a display device on the outer side of the sealing cover through a lead are arranged in the drill hole;
the heating drill hole comprises a sealing cover for plugging the hole of the drill hole, and a temperature sensor and a heating cable which are connected with display equipment outside the sealing cover through a lead are arranged in the drill hole;
the sealing cover is made of high-temperature-resistant or low-temperature-resistant materials and is used for plugging the cold injection drilling hole and the heating drilling hole respectively.
A downhole cooling and heating alternate working cycle fracturing permeability-increasing coal seam extraction method comprises the following steps:
step 4, continuously injecting low-temperature liquid nitrogen into the cold injection drill hole through a liquid nitrogen injection pipeline until the inside of the whole drill hole is filled, stopping injection, and screwing the manual pressure relief valve;
and 7, repeating the fourth step and the sixth step for 5-7 times, subjecting the coal bed to repeated cold and heat exchange impact, greatly improving air permeability, converting adsorbed coal bed gas into a free state under the displacement action of nitrogen, so that extraction is more thorough, taking out all sealing covers and heating cables of the cold injection drill holes and the heating drill holes, performing hole sealing extraction on all the cold injection drill holes and the heating drill holes, and extracting mixed gas of the coal bed gas and the nitrogen to obtain high-purity coal bed gas by a conventional separation method.
The radius of the cold injection drilling hole and the heating drilling hole is 60-120 mm, the hole depth is 50-150 m, and the distance between every two adjacent drilling holes is 1.2-2 m.
When the heat insulation plate is installed, bolts are used for fixing the heat insulation plate on the surface of the coal seam between every two cold injection drill holes and every two heating drill holes.
The injection cooling drilling and the heating drilling are downward drilling or horizontal drilling.
The cold drilling of notes and heating drilling are wet-type drilling or arrange drilling and finish the inside water that can not have obvious ponding and only drench the pore wall of injecting into of drilling, and the freezing fracturing effect of liquid nitrogen is effectively improved to moisture retained in the cold drilling of notes, and the thermal conductivity in moisture effectively increases the coal seam is retained in the heating drilling.
Advantageous effects
According to the invention, a large amount of low-temperature liquid nitrogen is injected into the cold hole, so that water in pores of the coal seam around the drill hole is gradually condensed into ice, and the fracture of the coal seam is expanded to different degrees due to volume expansion; the heating cable in the heating drill hole works continuously to enable the temperature of the coal bed to rise gradually, liquid nitrogen in the cold injection drill hole is enabled to be gasified rapidly, the air pressure in the drill hole rises rapidly, surrounding coal bed cracks are impacted to expand, and meanwhile nitrogen generated by the liquid nitrogen for refrigeration can also play a displacement role in coal bed gas adsorbed on the coal bed; the cold injection drilling and the heating drilling work cooperatively, so that the coal seam is subjected to cold impact and thermal impact alternately, and the air permeability of the coal seam is greatly improved. The method can greatly improve the extraction rate of the coal bed gas and has the advantages of simple operation and lower cost.
Drawings
FIG. 1 is a schematic view of a system for the cooperative operation of injection cooling drilling and heating drilling according to the present invention;
FIG. 2 is a schematic view of the injection cooling drilling and heating drilling distribution of the present invention;
FIG. 3 is a schematic view of the internal arrangement of the injection-cooled borehole of the present invention;
FIG. 4 is a schematic view of the internal layout of a heated borehole according to the present invention
In the figure: 1-cold injection drilling, 2-hot drilling, 3-sealing cover, 4-manual pressure relief valve, 5-safety valve, 6-pressure sensor, 7-liquid nitrogen injection pipeline, 8-temperature sensor, 9-heating cable, 10-thermal insulation board, 11-bolt.
Detailed Description
The technical solution in the embodiment of the present invention will be described below with reference to the drawings in the embodiment of the present invention.
As shown in fig. 2 and 3, the underground injection cooling and heating alternate working cycle cracking permeability-increasing coal seam system of the invention is characterized in that: the coal seam cooling and heating device comprises a plurality of cooling injection drill holes 1 and a plurality of heating drill holes 2, wherein the cooling injection drill holes 1 and the heating drill holes 2 are alternately arranged on a coal seam; a cold injection drilling hole 1 and a heating drilling hole 2;
the cold injection drill hole 1 comprises a sealing cover 3 for plugging a drill hole opening, the sealing cover 3 is respectively provided with a manual pressure relief valve 4 and a safety valve 5 which are communicated with the inside of the drill hole, and the inside of the drill hole is provided with a pressure sensor 6 and a liquid nitrogen injection pipeline 7 which are connected with a display device on the outer side of the sealing cover 3 through leads;
the heating drill hole 2 comprises a sealing cover 3 for plugging a drill hole opening, and a temperature sensor 8 and a heating cable which are connected with display equipment on the outer side of the sealing cover 3 through a lead are arranged in the drill hole;
the sealing cover 3 is made of high-temperature-resistant or low-temperature-resistant materials and is used for sealing the injection cooling drill hole 1 and the heating drill hole 2 respectively.
As shown in fig. 1 and 2, the method for extracting and fracturing the anti-reflection coal seam by using the underground injection cooling and heating alternating working cycle of claim 1 comprises the following steps:
step 4, continuously injecting low-temperature liquid nitrogen into the injection-cooling drill hole 1 through a liquid nitrogen injection pipeline 7 until the inside of the whole drill hole is filled, stopping injection, and screwing the manual pressure relief valve 4;
and 7, repeating the fourth step and the sixth step for 5-7 times, subjecting the coal bed to repeated cold and heat exchange impact, greatly improving air permeability, converting adsorbed coal bed gas into a free state under the displacement action of nitrogen, so that extraction is more thorough, taking out the sealing covers 3 and the heating cables 9 of all the cold injection drill holes 1 and the heating drill holes 2, performing hole sealing extraction on all the cold injection drill holes 1 and the heating drill holes 2, and performing a conventional separation method on mixed gas of the coal bed gas and the nitrogen to extract the high-purity coal bed gas.
The working principle is as follows:
cold injection drill holes 1 and heating drill holes 2 are reasonably and alternately arranged on the coal seam, and a large amount of low-temperature liquid nitrogen is injected into the cold injection drill holes 1 to generate cold impact on the coal seam around the drill holes, so that a coal body framework generates shrinkage stress, and a coal rock structure generates fine tensile damage; the ultralow temperature can also cause water in the fractures of the coal seam to be condensed into ice, and the volume expansion acts on the fractures to expand the fractures to a certain degree. The coal bed is heated through the heating cable 9 arranged in the heating drill hole 2, thermal shock is generated on the coal bed around the drill hole, the temperature of the coal bed gradually rises, thermal shock is generated on the coal bed, low-temperature liquid nitrogen in a cold hole can rapidly expand gas volume rapidly, and the fracturing and permeability-increasing effect on the coal bed is obvious; the nitrogen generated by gasification can also generate displacement effect on coal bed gas adsorbed by the coal bed, so that the coal bed gas is more thoroughly extracted. And the cold injection and the heating work cooperatively for 5-7 times to enable the coal seam to be subjected to cold and thermal shock alternately and a series of cracking and permeability increasing effects, so that the air permeability of the coal seam is obviously improved.
Claims (5)
1. The utility model provides a make and split permeability-increasing coal seam system of cold, heating alternation duty cycle in pit which characterized in that: the coal seam cooling system comprises a plurality of cold injection drill holes (1) and a plurality of heating drill holes (2), wherein the plurality of cold injection drill holes (1) and the plurality of heating drill holes (2) are alternately arranged on the coal seam; a cold injection drilling hole (1) and a heating drilling hole (2);
the cold injection drill hole (1) comprises a sealing cover (3) for plugging a drill hole opening, the sealing cover (3) is respectively provided with a manual pressure relief valve (4) and a safety valve (5) communicated with the inside of the drill hole, and a pressure sensor (6) and a liquid nitrogen injection pipeline (7) which are connected with a display device on the outer side of the sealing cover (3) through a lead are arranged in the drill hole;
the heating drill hole (2) comprises a sealing cover (3) for plugging a drill hole opening, and a temperature sensor (8) and a heating cable which are connected with a display device on the outer side of the sealing cover (3) through a lead are arranged in the drill hole;
the sealing cover (3) is made of high-temperature-resistant or low-temperature-resistant materials and is used for plugging the injection cooling drill hole (1) and the heating drill hole (2) respectively;
the extraction method of the underground injection cooling and heating alternate working cycle fracturing permeability-increasing coal seam system comprises the following steps:
step 1, alternately arranging cooling injection drill holes (1) and heating drill holes (2) on a coal seam;
step 2, paving a layer of heat insulation board (10) made of high-temperature and low-temperature resistant materials on the surface of the coal seam, and arranging reserved holes of the cold drilling hole (1) and the heating drilling hole (2) on the heat insulation board (10);
step 3, laying a heating cable (9) in the heating drill hole (2), and installing a heat-insulating sealing cover (3) at the hole openings of the cold injection drill hole (1) and the heating drill hole (2) respectively;
step 4, continuously injecting low-temperature liquid nitrogen into the injection cooling drill hole (1) through a liquid nitrogen injection pipeline (7) until the inside of the whole drill hole is filled, stopping injection, and screwing the manual pressure relief valve (4) to be dead;
step 5, electrifying the heating cable (9) to heat the coal bed, keeping the temperature in the drill holes of all the heating drill holes (2) at 100-120 ℃ by using the temperature sensor (8), continuously heating for 10-15 min, and then stopping heating;
step 6, opening a manual pressure relief valve (4) on a sealing cover (3) of the cold injection drill hole (1) to discharge nitrogen in the hole;
and 7, repeating the fourth step and the sixth step for 5-7 times, subjecting the coal bed to repeated cold and heat exchange impact, greatly improving air permeability, converting adsorbed coal bed gas into a free state under the displacement action of nitrogen, so that extraction is more thorough, taking out the sealing covers (3) and the heating cables (9) of all the cold injection drill holes (1) and the heating drill holes (2), performing hole sealing extraction on all the cold injection drill holes (1) and the heating drill holes (2), and performing a conventional separation method on mixed gas of the coal bed gas and the nitrogen to obtain high-purity coal bed gas.
2. The underground coal bed cooling and heating alternate working cycle fracturing and permeability increasing system according to claim 1, characterized in that: the radius of the injection cooling drill hole (1) and the radius of the heating drill hole (2) in the step 1 are 60-120 mm, the hole depth is 50-150 m, and the distance between the adjacent drill holes is 1.2-2 m.
3. The underground coal bed cooling and heating alternate working cycle fracturing and permeability increasing system according to claim 1, characterized in that: when the heat insulation plate (10) is installed, bolts (11) are used for fixing the heat insulation plate on the surface of the coal seam between every two cooling injection drill holes (1) and every two heating drill holes (2).
4. The underground coal bed cooling and heating alternate working cycle fracturing and permeability increasing system according to claim 1, characterized in that: the injection cooling drill hole (1) and the heating drill hole (2) are downward drill holes or horizontal drill holes.
5. The underground coal bed cooling and heating alternate working cycle fracturing and permeability increasing system according to claim 1, characterized in that: annotate cold drilling (1) and heating drilling (2) and be wet-type drilling or arrange drilling and finish the inside water that can not have obvious ponding and only drench the pore wall of injecting into of drilling into, reserve moisture in cold drilling (1) and effectively improve the frozen fracturing effect of liquid nitrogen, reserve the heat conductivity that moisture effectively increased the coal seam in heating drilling (2).
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910174682.0A CN109854221B (en) | 2019-03-08 | 2019-03-08 | Underground cooling and heating alternate working cycle fracturing and permeability increasing coal seam system and extraction method |
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| CN201910174682.0A CN109854221B (en) | 2019-03-08 | 2019-03-08 | Underground cooling and heating alternate working cycle fracturing and permeability increasing coal seam system and extraction method |
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| CN109854221B true CN109854221B (en) | 2020-09-04 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112855111B (en) * | 2019-11-28 | 2023-04-25 | 中国石油天然气股份有限公司 | Underground gasification system and method for electric heating coal bed |
| 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 |
| CN115434671B (en) * | 2022-09-10 | 2024-06-25 | 中国矿业大学 | Coal seam pressure relief and permeability improvement method and system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104314609B (en) * | 2014-09-28 | 2016-05-25 | 太原理工大学 | A kind of method for increasing that colds and heat succeed each other for drilling well for gas drainage |
| CN105134284B (en) * | 2015-08-03 | 2017-05-31 | 中国矿业大学 | One kind is based on horizontal orientation drilling liquid nitrogen circulating freezing resistance anti-reflection mash gas extraction method |
| CN207073410U (en) * | 2017-05-09 | 2018-03-06 | 河南理工大学 | The anti-reflection system of injection hot water and liquid nitrogen is circulated to coal seam |
| CN107100664B (en) * | 2017-05-10 | 2023-03-14 | 河南理工大学 | Hot-cold alternative coal breaking permeability-increasing gas enhanced extraction system and method |
| CN206769948U (en) * | 2017-05-10 | 2017-12-19 | 河南理工大学 | A kind of cold alternating of heat breaks coal permeability-increasing gas enhanced gas extraction system |
| CN107035402A (en) * | 2017-06-05 | 2017-08-11 | 贵州大学 | A kind of heating cable heats coal seam to increase the system and method for gas permeability of coal seam |
| CN107575185A (en) * | 2017-09-14 | 2018-01-12 | 辽宁工程技术大学 | A kind of method in underground using the effect extraction coal bed gas that colds and heat succeed each other |
| CN107575263A (en) * | 2017-09-30 | 2018-01-12 | 太原理工大学 | A kind of device of underground heat injection enhanced gas extraction gas |
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