CN113914846A - Method for improving development of underground coal gasification air cavity by applying double-feather horizontal well - Google Patents
Method for improving development of underground coal gasification air cavity by applying double-feather horizontal well Download PDFInfo
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- 239000003245 coal Substances 0.000 title claims abstract description 93
- 238000002309 gasification Methods 0.000 title claims abstract description 67
- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000011161 development Methods 0.000 title claims abstract description 19
- 238000002347 injection Methods 0.000 claims abstract description 75
- 239000007924 injection Substances 0.000 claims abstract description 75
- 238000004519 manufacturing process Methods 0.000 claims abstract description 59
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 10
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- 238000004891 communication Methods 0.000 claims abstract description 8
- 238000005553 drilling Methods 0.000 claims description 10
- 230000015572 biosynthetic process Effects 0.000 claims description 8
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- 239000007789 gas Substances 0.000 description 89
- 238000001179 sorption measurement Methods 0.000 description 16
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 12
- 230000008569 process Effects 0.000 description 11
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000010793 Steam injection (oil industry) Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 2
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- 239000003463 adsorbent Substances 0.000 description 1
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- 239000003034 coal gas Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010980 drying distillation Methods 0.000 description 1
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- E21B—EARTH OR ROCK 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
- E21B43/295—Gasification of minerals, e.g. for producing mixtures of combustible gases
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK 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
- E21B43/30—Specific pattern of wells, e.g. optimising the spacing of wells
- E21B43/305—Specific pattern of wells, e.g. optimising the spacing of wells comprising at least one inclined or horizontal well
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Abstract
The invention discloses a method for improving the development of an underground coal gasification air cavity by using a double-feather horizontal well, which comprises the following steps: s1: constructing an air inlet hole of the gas injection well; s2: constructing a horizontal branch well of the gas injection well; s3: constructing a gas production hole of a production well; s4: constructing a horizontal branch well of the production well; s5: constructing an auxiliary hole; s6: auxiliary devices such as an ignition device, a gasification agent injection device and a retreating device are arranged at the wellhead of the injection well; s7, injecting a gasifying agent at the horizontal branch well point for ignition; s8: after the gasification cavities of two adjacent horizontal branch wells at the finger ends are communicated, arranging the auxiliary device at the horizontal branch well point of the middle-rear section, and repeating the steps S5-S8 until the coal bed gas cavities at all the horizontal branch wells realize integral gasification and communication; and S9, installing an air extractor at the ground end of the production well. The application method of the invention can break through the point or line range injection and production limitation of the vertical well and the horizontal well, communicate with the coal seam fracture system in a large range, increase the reaction contact area and improve the gas production rate.
Description
Technical Field
The invention relates to the technical field of coal bed gas heat injection yield increase, in particular to a method for improving the development of an underground coal gasification air cavity by using a double-feather horizontal well.
Background
Underground coal gasification is a process in which coal located underground is burned in a controlled manner to produce combustible gases (CH4, H2, CO) by thermal and chemical action on the coal. The modern coal underground gasification process route is formed by integrating a modern drilling technology, advanced petroleum equipment and an underground measurement technology on the basis of a controllable back injection point (CRIP) gasification process route. Compared with the conventional coal mining process, the underground coal gasification process utilizes a chemical coal mining method to replace physical coal mining, realizes the underground in-situ conversion of coal into gaseous products, and has no solid waste discharge on the ground; coal is difficult to be used as a practical recoverable resource in a deep layer (1000-3000 m), so that the recoverable resource amount of the coal is greatly improved.
Due to the heat insulation and low permeability characteristics of rocks and coals in the deep coal seam, synthetic gas generated by underground coal gasification is difficult to flow in the coal seam and the rock stratum, so that gas generated by coal gasification and released heat after ignition are easily limited in a small range, the formation and development of a gasification cavity are influenced, a far field effect is difficult to form, meanwhile, local high temperature is easily formed at the ignition part of a horizontal well to damage the horizontal well, and production accidents are caused. Overcoming this problem can be achieved by improving permeability in the near wellbore region, accelerating the early rapid development of the air cavity, and increasing connectivity between production injection wells.
The invention provides a method for improving the development of an underground coal gasification gas cavity by using a double-feather horizontal well, namely, a feather-shaped horizontal branch production well and a feather-shaped branch injection well are respectively drilled into the top and the bottom of a target coal seam, the horizontal branch well at the finger end of the injection well is firstly ignited to form a gas cavity, and the horizontal branch well is communicated through a corresponding production branch well right above the horizontal branch well, so that an independent gasification furnace is established; the step is repeated, independent gasification furnaces can be sequentially formed at a plurality of branch well points at the finger ends, and the gasification furnaces are communicated with each other along with the development of the independent air cavities, so that the conversion from points to lines is realized; when the gasification furnace at the finger end is expanded to a certain degree, the igniter in the horizontal injection well is moved to a branch well point at the middle rear part of the horizontal well for ignition, the gasification furnace is built on the horizontal section by repeating the process, and the formed gasification furnace is communicated with the previously formed air cavity after being developed to a certain degree, so that the transformation from a line to a surface is realized, and finally, a large-scale air cavity is formed. The method not only improves the convection effect of the gas diffusion rate and heat, avoids accidents such as blowout of a steam injection well and explosion and fire hazard of ground facilities caused by local high temperature, but also greatly reduces the floor area of ground well drilling, saves the well drilling time, increases the coal yield of a single well and obviously improves the production efficiency.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a method for improving the development of an underground coal gasification air cavity by using a double-feather horizontal well
A deep coal underground gasification furnace, comprising:
the injection well comprises a vertical section and a horizontal section, the vertical section is communicated with the ground surface and a target coal seam, and the horizontal section is positioned near the bottom of the coal seam;
an injection well horizontal laterals in communication with the injection well horizontal section;
the production well comprises a vertical section and a horizontal section, the vertical section is communicated with the earth surface and the target coal seam, and the horizontal section is positioned near the top of the coal seam;
the production well horizontal branch well is communicated with the production well horizontal section, and the production horizontal branch well and the injection horizontal branch well are correspondingly distributed along the horizontal section;
and the top end of the auxiliary hole is positioned on the earth surface, the bottom end of the auxiliary hole is communicated with the horizontal section of the gas injection well, and the auxiliary hole and the vertical section of the gas injection well are respectively arranged at two ends of the horizontal section of the gas injection well.
The technical scheme adopted by the invention is as follows: a method for improving the development of an underground coal gasification gas cavity by using a dual-feather horizontal well comprises the following steps:
s1: constructing an air inlet of a gas injection well, wherein the air inlet comprises a vertical section and a horizontal section, the vertical section is communicated with the earth surface and a target coal seam, and the horizontal section is positioned near the bottom of the coal seam;
s2: constructing a horizontal branch well of the gas injection well, wherein the horizontal branch well is communicated with the horizontal section of the gas injection well gas inlet;
s3: constructing a gas production hole of a production well, wherein the gas production hole comprises a vertical section and a horizontal section, the vertical section is communicated with the earth surface and a target coal seam, and the horizontal section is positioned in a near coal seam;
s4: constructing horizontal branch wells of a production well, wherein the horizontal branch wells are communicated with the horizontal sections of gas production holes of the production well, and the horizontal branch wells correspond to the horizontal branch wells of the gas injection well one to one;
s5: the top end of the auxiliary hole is positioned on the ground surface, the bottom end of the auxiliary hole is communicated with the horizontal section of the gas injection well, and the auxiliary hole and the vertical section of the gas injection well are respectively arranged at two ends of the horizontal section of the gas injection well;
s6, a series of underground coal gasification auxiliary devices such as an ignition device, a gasifying agent injection device and a retreating device are put into the well mouth of the injection well to reach the finger end branch well of the horizontal well;
s7, injecting a gasifying agent into the horizontal branch well point, igniting to form a high-temperature oxidation area for underground coal gasification, and starting coal combustion to generate high-temperature gas to form a synthesis gas cavity; high heat generated by coal combustion is quickly diffused along the branch well channel, the coal near the channel is heated and gasification reaction occurs, the gasification cavity is promoted to grow from the horizontal branch well of the injection well to the horizontal branch well of the production well, and the risk of local high-temperature accumulation of the well section at the ignition position is reduced;
s8: after the gasification cavities of two adjacent horizontal branch wells at the finger ends form point-to-line communication, the ignition and related auxiliary devices are arranged at the horizontal branch well points at the middle and rear sections, the steps S5-S7 are repeated to establish a new air cavity and realize large-area communication with the previously formed air cavity, and the steps are repeated until the coal bed air cavities at all the horizontal branch wells realize integral gasification and communication;
s9, installing an air extraction device at the ground end of the production well, enabling the synthesis gas generated by underground coal gasification to enter a horizontal branch well of the production well and be discharged out of the ground;
further, in the steps S1 and S3, the length of the horizontal section is 300-1500 m.
Further, in the above steps S1 and S3, the horizontal section should be parallel to the fracture direction or the main stress direction of the target coal seam.
Further, in the steps S2 and S4, the included angle between the horizontal branch well and the horizontal section part is between 30 ° and 45 °, and the horizontal distribution distance is 40-120 m.
Further, in the above steps S2 and S4, the horizontal branch wells should be symmetrically disposed on both sides of the horizontal segment.
Further, in the above steps S2 and S4, the horizontal wells are grouped into at least two wells, the drilling point of the first horizontal well is 130 meters or more according to the auxiliary hole, and the distance between the drilling points of each horizontal well is 140 meters.
Further, in the above steps S1, S2, S3, S4 and S5, a supporting device should be provided in all the boreholes.
Further, the supporting device is a protection structure of the drill hole, for example, a casing is arranged, a protection structure such as a cement sheath is constructed on the outer side of the casing, and the like.
Has the advantages that:
compared with the prior art, the invention has the beneficial effects that:
1. the number of drilled holes of the horizontal well, economic cost and time cost are reduced.
2. The system breaks through the limitation of point or line range injection and production of the vertical well and the horizontal well, has the characteristics of large control area and strong flow guiding capability, and can communicate with a coal seam fracture system in a large range.
3. The contact area of the reaction is increased, the gas diffusion rate and the heat convection effect are improved, and the formation and the development of the underground gasification cavity are promoted.
4. The accidents of blowout of the steam injection well, explosion of ground facilities, fire and the like caused by local high temperature are avoided.
5. The recovery rate of the synthetic gas is obviously improved.
Drawings
Fig. 1 is a schematic structural diagram of an underground coal gasification furnace provided in an embodiment of the present invention.
Detailed Description
For the purpose of enhancing the understanding of the present invention, the present invention will be further explained with reference to the accompanying drawings and examples, which are only for the purpose of explaining the present invention and do not limit the scope of the present invention.
Example (b):
as shown in fig. 1, a furnace body structure of a bi-level feather-shaped coal underground gasification furnace provided by an embodiment of the present invention includes: the gas injection well comprises a gas injection well gas inlet 1, a gas injection well horizontal branch well 2, a production well gas production hole 3, a production well horizontal branch well 4 and an auxiliary hole 5; the gas injection well gas inlet 1 comprises a vertical section 1.1 and a horizontal section 1.2 communicated with the vertical section 1.1, wherein the ground surface is communicated with a target coal seam, and the horizontal section 1.2 is positioned near the bottom of the coal seam; the gas production hole 3 of the production well comprises a vertical section 3.1 and a horizontal section 3.2 communicated with the vertical section 3.1, wherein the ground surface is communicated with a target coal seam by the vertical section 3.1, and the horizontal section 3.2 is positioned near the bottom of the coal seam; the gas injection well horizontal branch wells 2 correspond to the production well horizontal branch wells 4 one by one; the top end of the auxiliary hole 5 is positioned on the earth surface, the bottom end of the auxiliary hole is communicated with the horizontal section of the gas injection well, and the auxiliary hole 5 and the vertical section 1.1 of the gas injection well gas inlet are respectively arranged at two ends of the horizontal section 1.2 of the gas injection well gas inlet.
As shown in fig. 1, a method for constructing an underground coal gasification furnace according to an embodiment of the present invention includes the following steps:
s1, constructing a vertical section 1.1 of an air inlet hole of the gas injection well, and putting a casing and cementing the well. And constructing a gas injection well gas inlet horizontal section 1.2 2 m above the bottom plate of the target coal seam, and putting a casing and cementing the well.
S2, constructing a gas injection horizontal branch well group 2.1 at a G1 target point, setting a casing and cementing wells at a position which is more than 5100 meters away from an auxiliary hole at the G1 target point; constructing a gas injection well horizontal branch well group 2.2 at a G2 target point, enabling the G2 target point to be 140 meters away from the G1 target point, setting a casing and cementing; and (3) repeating the construction process of the gas injection well horizontal directional drilling group 2.2 by the gas injection well horizontal branch well group 2.3.
S3, constructing a vertical section 3.1 of a gas production hole of the production well, and setting a casing and cementing the well. And constructing a horizontal section 3.2 of a gas production hole of the production well 2-3 meters below the target coal seam roof, and setting a casing and cementing the well.
And S4, repeating the construction process of the gas injection well horizontal multilateral well 2 by the production well horizontal multilateral well 4.
And S5, drilling an auxiliary construction hole 5 from the ground surface to a target coal seam, wherein the bottom end of the auxiliary construction hole is communicated with the horizontal section 1.2 of the gas injection well gas inlet hole.
S6, a series of auxiliary devices for underground coal gasification, such as an ignition device, a gasification agent injection device, a retreating device and the like, are put into the first group of horizontal branch wells through the wellhead of the gas injection well;
s7, injecting a gasifying agent at the G1 target spot, igniting to form a high-temperature oxidation zone for underground coal gasification, and starting coal combustion to generate high-temperature gas to form a synthesis gas cavity; high heat generated by coal combustion is quickly diffused along a branch well channel, the coal near the channel is heated, the coal is promoted to generate reduction reaction, incomplete combustion reaction and drying and dry distillation reaction, a synthetic gas cavity is promoted to develop from a horizontal branch well group 2.1 of a gas injection well to a horizontal branch well group 4.1 of a production well, and the risk of local high temperature near an auxiliary device is reduced; the reaction generates a series of high-temperature mixed gases;
s8: after the coal seam production at the first group of gas injection well horizontal branch wells 2.1 is finished, the upper-complaint auxiliary device is arranged at the G2 target point, and the step S5 is repeated until the whole area is mined.
S9, installing an air extractor at the ground end of the production well to make the synthetic gas generated by underground coal gasification enter the horizontal branch well 4 of the production well and be discharged out of the ground from the gas generating hole 3 of the production well;
in the embodiment, the length of the horizontal section 1.2 of the gas inlet hole of the gas injection well depends on the construction technology level of directional drilling and the practical gasification requirement, and the length of the horizontal section is generally 300-1500 meters and is parallel to the crack direction or the main stress direction of a target coal seam. The length of the gas injection well horizontal branch well 2 and the production well horizontal branch well 4 is 40-150 meters, the included angle between the gas injection well horizontal section 1.2 and the production well gas production hole horizontal section 3.2 is 30-45 degrees, and the gas injection well horizontal section and the production well gas production hole horizontal section are respectively arranged on two sides of the gas injection well horizontal section 1.2 and are symmetrically distributed.
In this embodiment, all the drill holes should be provided with a supporting device, and the supporting device is a protection structure of the drill hole, such as a casing pipe, a protection structure such as a cement sheath constructed outside the casing pipe, and the like.
In the embodiment, when gasification is carried out, a series of auxiliary devices for underground coal gasification such as an ignition device, a gasifying agent injection device, a retreating device and the like are put into a G1 target point through an air inlet 1 of the gas injection well, underground coal gasification is carried out through the horizontal branch well 2 of the gas injection well, synthetic gas enters the horizontal branch well 4 of the production well, and the generated synthetic gas is output through an air outlet 3 of the production well.
In the embodiment, in the underground gasification process, the gas injection well horizontal branch well 2 comprises a plurality of gas injection targets G1, G2, G3 and the like, the auxiliary device is arranged at the G1 target for gas injection gasification, when the gasification at the first group of gas injection well horizontal branch well 2.1 is finished, if the design of the production reserve and/or the content and the heat value of effective components of coal gas are obviously reduced and cannot be adjusted by changing technological parameters, the auxiliary device is moved back to the G2 target for gas injection gasification, and the operation of the auxiliary device is repeated until the production of the whole area is finished. The determination of each gas injection target point and the distance between the gas injection target points is determined according to different equipment and specific gasification requirements.
In this embodiment, the auxiliary holes 5 have a plurality of functions: firstly, the exhaust gas is used as an auxiliary vent hole to discharge various exhaust gases; and secondly, as a target point, in the construction process of the underground coal gasification furnace, constructing the auxiliary hole 5 in advance, and then constructing other drilled holes by taking the auxiliary hole 5 as the target point.
In the embodiment, a normal-temperature gasification agent for underground coal gasification enters a coal bed from a gas injection well, reaches a gasification combustion cavity in the coal bed, reacts with coal to form high-temperature gases such as CH4, CO2 and H2, the high-temperature gases are continuously gathered to form a synthesis gas cavity through a crack channel, heat is continuously diffused to heat the surrounding coal bed gas cavity to develop, and then the gases are transported to the ground under the action of the pressure difference of reservoir pressure between the ground and the ground, the method for calculating the real adsorption quantity of methane in shale based on the adsorption potential theory is provided, the method is based on the adsorption potential theory, a correction D-A isothermal adsorption model has a clear physical background, overcomes the defects of a common Langmuir isothermal adsorption model, combines the test data of supercritical isothermal adsorption experiments, and adopts the idea of cycle iteration and optimization in the process of solving model parameters and the density of adsorption phase methane at various temperatures, the obtained model parameters and the density of the adsorption phase methane can enable the adsorption potential and the volume of the adsorption phase under each temperature and pressure to be on the same adsorption characteristic curve, so that the obtained density and the real adsorption quantity of the adsorption phase can well meet the adsorption potential theory and the optimization theory, and the obtained result is more reasonable and reliable. The method can be used for calculating the true adsorption quantity of methane in shale, can also be popularized and used for calculating the true adsorption quantity of methane in adsorbents such as coal, activated carbon and the like, and has wide application value.
The embodiments of the present invention are disclosed as the preferred embodiments, but not limited thereto, and those skilled in the art can easily understand the spirit of the present invention and make various extensions and changes without departing from the spirit of the present invention.
Claims (8)
1. A method for improving the development of an underground coal gasification gas cavity by using a double-feather horizontal well is mainly characterized by comprising the following steps: the method comprises the following steps:
s1: constructing an air inlet of a gas injection well, wherein the air inlet comprises a vertical section and a horizontal section, the vertical section is communicated with the earth surface and a target coal seam, and the horizontal section is positioned near the bottom of the coal seam;
s2: constructing a horizontal branch well of the gas injection well, wherein the horizontal branch well is communicated with the horizontal section of the gas injection well gas inlet;
s3: constructing a gas production hole of a production well, wherein the gas production hole comprises a vertical section and a horizontal section, the vertical section is communicated with the earth surface and a target coal seam, and the horizontal section is positioned in a near coal seam;
s4: constructing horizontal branch wells of a production well, wherein the horizontal branch wells are communicated with the horizontal sections of gas production holes of the production well, and the horizontal branch wells correspond to the horizontal branch wells of the gas injection well one to one;
s5: the top end of the auxiliary hole is positioned on the ground surface, the bottom end of the auxiliary hole is communicated with the horizontal section of the gas injection well, and the auxiliary hole and the vertical section of the gas injection well are respectively arranged at two ends of the horizontal section of the gas injection well;
s6, a series of underground coal gasification auxiliary devices such as an ignition device, a gasifying agent injection device and a retreating device are put into the well mouth of the injection well to reach the finger end branch well of the horizontal well;
s7, injecting a gasifying agent into the horizontal branch well point, igniting to form a high-temperature oxidation area for underground coal gasification, and starting coal combustion to generate high-temperature gas to form a synthesis gas cavity; high heat generated by coal combustion is quickly diffused along the branch well channel, the coal near the channel is heated and gasification reaction occurs, the gasification cavity is promoted to grow from the horizontal branch well of the injection well to the horizontal branch well of the production well, and the risk of local high-temperature accumulation of the well section at the ignition position is reduced;
s8: after the gasification cavities of two adjacent horizontal branch wells at the finger ends form point-to-line communication, the ignition and related auxiliary devices are arranged at the horizontal branch well points at the middle and rear sections, the steps S5-S7 are repeated to establish a new air cavity and realize large-area communication with the previously formed air cavity, and the steps are repeated until the coal bed air cavities at all the horizontal branch wells realize integral gasification and communication;
and S9, installing an air extraction device at the ground end of the production well, so that the synthesis gas generated by underground coal gasification enters the horizontal branch well of the production well and is discharged out of the ground.
2. The method for improving the development of the underground coal gasification air cavity by using the double-feather horizontal well as defined in claim 1 is characterized in that: in the above steps S1 and S3, the length of the horizontal section is 300-1500 m.
3. The method for improving the development of the underground coal gasification air cavity by using the double-feather horizontal well as defined in claim 1 is characterized in that: in the above steps S1 and S3, the horizontal segment should be parallel to the fracture direction or the main stress direction of the target coal seam.
4. The method for improving the development of the underground coal gasification air cavity by using the double-feather horizontal well as defined in claim 1 is characterized in that: in the steps S2 and S4, the included angle between the horizontal branch well and the horizontal section part is between 30 degrees and 45 degrees, and the horizontal distribution distance is 40-120 meters.
5. The method for improving the development of the underground coal gasification air cavity by using the double-feather horizontal well as defined in claim 1 is characterized in that: in the above steps S2 and S4, the horizontal branch wells are symmetrically disposed on both sides of the horizontal segment.
6. The method for improving the development of the underground coal gasification air cavity by using the double-feather horizontal well as defined in claim 1 is characterized in that: in the above steps S2 and S4, the horizontal wells are grouped into at least two wells, the drilling point of the first horizontal well is 130 meters or more according to the auxiliary hole, and the distance between the drilling points of each horizontal well is 140 meters.
7. The method for improving the development of the underground coal gasification air cavity by using the double-feather horizontal well as defined in claim 1 is characterized in that: in the above steps S1, S2, S3, S4 and S5, a supporting device should be provided in all the boreholes.
8. The method for improving the development of the underground coal gasification air cavity by using the double-feather horizontal well as defined in claim 1 is characterized in that: the supporting device is a protection structure of a drill hole, for example, a sleeve is arranged, and a cement sheath and other protection structures are constructed on the outer side of the sleeve.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114856518A (en) * | 2022-05-09 | 2022-08-05 | 大连理工大学 | Method for increasing production of coal bed gas by using medium-low enthalpy dry rock geothermal energy |
| CN117823112A (en) * | 2024-03-06 | 2024-04-05 | 太原理工大学 | In-situ coal supercritical water gasification hydrogen production different-layer mining method and device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101382061A (en) * | 2007-09-07 | 2009-03-11 | 新奥科技发展有限公司 | Novel coalbed gas thermal recovery process |
| CN103437748A (en) * | 2013-09-04 | 2013-12-11 | 新奥气化采煤有限公司 | Underground coal gasifying furnace and underground coal gasifying method |
| CN104695933A (en) * | 2015-02-13 | 2015-06-10 | 新奥气化采煤有限公司 | Gasification method and gasification furnace of coal seams based on branch wells |
| CN110924919A (en) * | 2019-12-11 | 2020-03-27 | 中国矿业大学 | Method for increasing production of coal bed gas by waste heat in underground coal gasification process |
| CN111963109A (en) * | 2020-07-20 | 2020-11-20 | 西山煤电(集团)有限责任公司钻探分公司 | Multi-branch horizontal well coal mining goaf gas extraction process |
| CN214366024U (en) * | 2021-02-04 | 2021-10-08 | 中为(上海)能源技术有限公司 | Gasification furnace for underground coal gasification |
-
2021
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101382061A (en) * | 2007-09-07 | 2009-03-11 | 新奥科技发展有限公司 | Novel coalbed gas thermal recovery process |
| CN103437748A (en) * | 2013-09-04 | 2013-12-11 | 新奥气化采煤有限公司 | Underground coal gasifying furnace and underground coal gasifying method |
| CN104695933A (en) * | 2015-02-13 | 2015-06-10 | 新奥气化采煤有限公司 | Gasification method and gasification furnace of coal seams based on branch wells |
| CN110924919A (en) * | 2019-12-11 | 2020-03-27 | 中国矿业大学 | Method for increasing production of coal bed gas by waste heat in underground coal gasification process |
| CN111963109A (en) * | 2020-07-20 | 2020-11-20 | 西山煤电(集团)有限责任公司钻探分公司 | Multi-branch horizontal well coal mining goaf gas extraction process |
| CN214366024U (en) * | 2021-02-04 | 2021-10-08 | 中为(上海)能源技术有限公司 | Gasification furnace for underground coal gasification |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114856518A (en) * | 2022-05-09 | 2022-08-05 | 大连理工大学 | Method for increasing production of coal bed gas by using medium-low enthalpy dry rock geothermal energy |
| CN117823112A (en) * | 2024-03-06 | 2024-04-05 | 太原理工大学 | In-situ coal supercritical water gasification hydrogen production different-layer mining method and device |
| CN117823112B (en) * | 2024-03-06 | 2024-04-30 | 太原理工大学 | In-situ coal supercritical water gasification hydrogen production different-layer mining method and device |
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Application publication date: 20220111 |