CN108005632B - Underground coal gasifier and gasification method - Google Patents
Underground coal gasifier and gasification method Download PDFInfo
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- CN108005632B CN108005632B CN201711136168.5A CN201711136168A CN108005632B CN 108005632 B CN108005632 B CN 108005632B CN 201711136168 A CN201711136168 A CN 201711136168A CN 108005632 B CN108005632 B CN 108005632B
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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
- E21B43/295—Gasification of minerals, e.g. for producing mixtures of combustible gases
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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
- E21B43/30—Specific pattern of wells, e.g. optimizing the spacing of wells
- E21B43/305—Specific pattern of wells, e.g. optimizing the spacing of wells comprising at least one inclined or horizontal well
Abstract
The invention discloses a coal underground gasification furnace and a gasification method, wherein the coal underground gasification furnace comprises an air inlet, a plurality of air outlets and a plurality of horizontal directional drilling holes, the air inlet comprises a vertical section and a horizontal section which are communicated, the top end of the vertical section is positioned on the ground surface, and the horizontal section is positioned in a coal seam; the top end of each exhaust hole is positioned on the ground surface, and the bottom end of each exhaust hole is positioned in the coal bed; each horizontal directional drilling hole corresponds to each vent hole one by one, and two ends of each horizontal directional drilling hole are respectively communicated with the bottom end of each vent hole and the horizontal section. According to the underground coal gasifier and the gasification method, provided by the invention, the single long-distance air inlet is matched with the plurality of air outlet holes, so that the coal exploitation quantity of the single hole is improved; meanwhile, the horizontal directional drilling can be set shorter, so that the gasification process of mobile gas injection can be conveniently controlled.
Description
Technical Field
The invention relates to a coal exploitation technology, in particular to an underground coal gasifier and a gasification method.
Background
The underground coal gasifying technology is one kind of coal mining technology to burn underground coal directly and controllably to produce inflammable gas through the heat and chemical action of coal. In the underground coal gasification technology, a series of holes for connecting the earth surface and the coal seam, such as an air inlet hole for delivering gasifying agent (such as air, oxygen, etc.) into the coal seam, an air outlet hole for outputting combustible gas (such as methane, hydrogen, carbon monoxide) from underground, etc., are required to be formed, and it is obvious that horizontal holes are also required to be formed in the coal seam so as to communicate the air inlet hole with the air outlet hole, and the whole channel system consisting of the holes extending from the earth surface into the coal seam and the holes formed in the coal seam is known as an underground gasifier.
The underground gasification furnace in the prior art comprises a chessboard type gasification furnace and a directional drilling through type gasification furnace, wherein the chessboard type gasification furnace is industrially applied by the soviet union, typically, a Moscow suburban gasification station is adopted as a vertical drilling hole for air inlet and a gas outlet, generally, one gasification furnace comprises a plurality of rows (or columns) of vertical drilling holes, each row (or column) of vertical drilling holes comprises a plurality of vertical drilling holes, in the operation process of the gasification furnace, the gasification is carried out according to the sequence of the rows (or columns), for example, a first row (or column) is used as a gas outlet hole, a second row is used as a gas inlet hole, after the coal bed between the first row and the second row is gasified, the gas is fed through a third row of drilling holes, the gas is discharged through a second row of drilling holes, and so on until the coal mining of the area is completed.
A typical gasification station of a directional drilling through-type gasifier is An Gelin, which comprises a plurality of vertical drilling holes and a directional drilling hole arranged in a coal seam and communicated with the two vertical drilling holes, wherein each vertical drilling hole is respectively used as an air inlet drilling hole and an air outlet drilling hole, the directional drilling hole is mainly used as a gasification channel, expansion of a gasification working surface is guided on the directional drilling hole for controlling the air injection position, and a plurality of vertical drilling holes can be drilled along the directional drilling hole to serve as auxiliary air inlet holes and air outlet holes.
The underground gasification furnace mainly comprises drilling holes, and the economic cost and the time cost for drilling holes, especially horizontal drilling holes in coal beds are high, so that in the underground coal mining process, the drilling holes are desirably reduced as much as possible, the single-hole coal mining amount is increased, and the production cost of combustible gas is reduced.
The prior art has the defects that the drilling intervals of the two types of underground gasifiers, namely, the chessboard gasifiers are generally 10-50 m and usually about 20m, so that the gasifiers have excessive drilling numbers, the time cost consumed by drilling is excessive, and the amount of coal produced by unit drilling is low; the number of vertical holes of the directional drilling through type gasifier is much smaller than that of the chessboard type gasifier, but the length of the directional drilling is longer, the size of the directional drilling is generally 100-300 m, so that the directional drilling is overlong, the movement of the gas injection point in the gas injection process is inconvenient, and a plurality of vertical holes still need to be used as auxiliary gas inlets.
Disclosure of Invention
The invention aims to provide an underground coal gasifier and a gasification method, which are used for solving the defects in the prior art.
In order to achieve the above object, the present invention provides the following technical solutions:
an underground coal gasifier comprising:
the air inlet comprises a vertical section and a horizontal section which are communicated, the top end of the vertical section is positioned on the ground surface, and the horizontal section is positioned in the coal seam;
the top end of each vent hole is positioned on the ground surface, and the bottom end of each vent hole is positioned in the coal seam;
the horizontal directional drilling holes are in one-to-one correspondence with the exhaust holes, and two ends of each horizontal directional drilling hole are respectively communicated with the bottom ends of the exhaust holes and the horizontal section.
The above-mentioned coal underground gasification stove still includes:
the top of auxiliary hole is located the earth's surface, the bottom with the horizontal segment is linked together, auxiliary hole with vertical section divides to arrange in the relative both ends of horizontal segment.
According to the underground coal gasifier, the exhaust holes are divided into two rows, and the two rows of exhaust holes are respectively arranged on two opposite sides of the horizontal section.
According to the underground coal gasifier, the included angle between the horizontal directional drilling hole and the part, far away from the vertical section, of the horizontal section is between 15 and 90 degrees.
The distance between the horizontal sections of the coal underground gasification furnace is 150-1500 meters, and the distance between the horizontal directional drilling holes is 100-300 meters.
According to the underground coal gasifier, the horizontal section and/or each horizontal directional drilling hole is provided with the supporting structure.
According to the underground coal gasifier, the horizontal section is located in the crack direction or the main stress direction of the coal seam.
An underground coal gasification method, comprising the following steps:
a101, drilling an air inlet hole, wherein the air inlet hole comprises a vertical section and a horizontal section which are communicated, the top end of the vertical section is positioned on the ground surface, and the horizontal section is positioned in a coal seam;
a102, drilling a first vent hole, wherein the top end of the vent hole is positioned on the ground surface, and the bottom end of the vent hole is positioned in the coal seam;
a103, drilling a first horizontal directional drilling hole, wherein two ends of the horizontal directional drilling hole are respectively communicated with the bottom end of the exhaust hole and the horizontal section;
a104, the gas injection device is downwards arranged into the first horizontal directional drilling hole through the gas inlet hole to carry out underground gasification, and gasified gas is output to the ground surface through the gas outlet hole;
a105, after the first horizontal directional drilling underground gasification is completed, circulating the steps A102-A104 to drill a plurality of exhaust holes and horizontal directional drilling holes, and correspondingly carrying out underground gasification.
According to the underground coal gasification method, before the first exhaust hole is drilled, the method further comprises the following steps:
a101', drilling an auxiliary hole, wherein the top end of the auxiliary hole is positioned on the ground surface, the bottom end of the auxiliary hole is designed to be communicated with a horizontal section which is subsequently drilled, and the auxiliary hole and the vertical section are respectively arranged at two opposite ends of the horizontal section.
In the above-mentioned underground coal gasification method, in the step of underground gasification from the gas injection device to the first horizontal directional drilling hole through the gas inlet hole,
the horizontal directional drilling hole comprises a plurality of gas injection positions, and the gas injection device moves from one end close to the gas exhaust hole to one end close to the horizontal directional drilling hole and performs gas injection gasification at each gas injection position.
The above-mentioned underground coal gasification method, after the step of carrying out underground gasification by the gas injection device which is put into the first horizontal directional drilling hole through the gas inlet hole, further comprises:
and A106, plugging the corresponding exhaust holes and/or horizontal directional drilling holes after underground gasification is finished.
According to the underground coal gasification method, the step of plugging the corresponding vent hole after underground gasification is completed comprises the following steps:
protective gas is input through the air inlet hole to carry out ventilation protection on the plugging position.
An underground coal gasification method is characterized by comprising the following steps:
b101, drilling an air inlet hole, wherein the air inlet hole comprises a vertical section and a horizontal section which are communicated, the top end of the vertical section is positioned on the ground surface, and the horizontal section is positioned in a coal seam;
b102, drilling a plurality of exhaust holes, wherein the top ends of the exhaust holes are positioned on the ground surface, and the bottom ends of the exhaust holes are positioned in the coal seam;
b103, drilling a first horizontal directional drilling hole, wherein two ends of the horizontal directional drilling hole are communicated with the bottom end of one of the exhaust holes and the horizontal section;
b104, entering an air injection device into the first horizontal directional drilling hole through the air inlet hole to carry out underground gasification, and outputting gasified coal gas to the ground surface through an air outlet hole;
and B105, after the underground gasification of the first horizontal directional drilling hole is completed, circulating the steps B103-B104 to drill a plurality of horizontal directional drilling holes, wherein each horizontal directional drilling hole corresponds to each vent hole one by one, and the underground gasification is correspondingly carried out.
In the technical scheme, the coal underground gasification furnace provided by the invention has the advantages that the single long-distance air inlet is matched with the plurality of air outlet holes, so that the coal exploitation quantity of the single hole is improved; meanwhile, the horizontal directional drilling can be set shorter, so that the gasification process of mobile gas injection can be conveniently controlled.
Because the underground coal gasifier has the technical effects, the underground gasification method corresponding to the underground coal gasifier has the corresponding technical effects.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings may be obtained according to these drawings for a person having ordinary skill in the art.
FIG. 1 is a schematic diagram of a coal underground gasifier according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a coal underground gasifier in a coal seam section according to an embodiment of the present invention;
FIG. 3 is a sequence diagram of the operation of the underground coal gasification method according to the embodiment of the invention;
FIG. 4 is a block flow diagram of a method for underground gasification of coal according to one embodiment of the present invention;
FIG. 5 is a block flow diagram of a method for underground gasification of coal in accordance with another embodiment of the present invention;
FIG. 6 is a block flow diagram of a method for underground gasification of coal in accordance with yet another embodiment of the present invention.
Reference numerals illustrate:
1. an air inlet hole; 1.1, vertical section; 1.2, horizontal segment; 2. an exhaust hole; 3. horizontally directional drilling; 4. an auxiliary hole; 5. an air injection device;
a1 to A6, B1 to B6, and the serial numbers of the exhaust holes; c1, numbering auxiliary holes; d1, numbering of air inlet holes; E1-E6, F1-F6, numbering of horizontal directional drilling; G1-G4, gas injection position numbers; S1-S6, numbering the crossing points of the horizontal directional drilling holes and the air inlet holes.
Detailed Description
In order to make the technical scheme of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings.
In the present invention, terms such as "top", "bottom", "horizontal", "vertical", etc., relating to orientation are relative terms, such as for a hole-like structure, the portion located on the ground is the top of the underground portion, whereas the bottom is horizontal parallel to the ground, vertical to the ground, and so on, with respect to the environment in which the coal underground gasifier is actually located.
As shown in fig. 1-3, the underground coal gasifier provided by the embodiment of the invention comprises an air inlet hole 1, a plurality of air outlet holes 2 and a plurality of horizontal directional drilling holes 3, wherein the air inlet hole 1 comprises a vertical section 1.1 and a horizontal section 1.2 which are communicated, the top end of the vertical section 1.1 is positioned on the ground surface, and the horizontal section 1.2 is positioned in a coal seam; the top end of each exhaust hole 2 is positioned on the ground surface, and the bottom end of each exhaust hole is positioned in the coal bed; each horizontal directional drilling hole 3 corresponds to each exhaust hole 2 one by one, and two ends of each horizontal directional drilling hole 3 are respectively communicated with the bottom end of each exhaust hole 2 and the horizontal section 1.2.
Specifically, the air inlet end of the air inlet hole 1 is positioned on the ground surface, one end of the air inlet hole 1 positioned between the ground surface and the coal seam is a straight hole, for example, a vertical hole-shaped structure vertical to the ground surface is a vertical section 1.1, the part of the air inlet hole 1 positioned in the coal seam is a horizontal hole-shaped structure parallel to the ground surface, and the part of the air inlet hole is a horizontal section 1.2. The vertical section 1.1 and the horizontal section 1.2 may be directly connected, i.e. one end of the horizontal section 1.2 is connected to the bottom end of the horizontal section 1.2, and the vertical section 1.1 and the horizontal section 1.2 may also be connected through other pipe structures, such as through an arc-shaped channel or an inclined channel. The number of the exhaust holes 2 is a plurality of, preferably vertical holes, the exhaust holes 2 can be in one row or in a plurality of rows, the number and the positions of the exhaust holes are determined according to the actual gasification condition, and the bottom end of the exhaust hole 2 is positioned in the coal seam and is positioned at or substantially at the same depth as the water section. Each exhaust hole 2 is communicated with each horizontal directional drilling hole 3 in a one-to-one correspondence manner, and two ends of each horizontal directional drilling hole 3 are respectively communicated with the bottom ends of the horizontal section 1.2 and the exhaust holes 2.
In this embodiment, the length of the horizontal directional drilling 3 is generally between 100 and 300 meters. The length of the water section of the air inlet hole 1 depends on the construction technology level of directional drilling and the practical gasification requirement, the length of the air inlet hole is generally 150-1500 m, and the distance between the air outlet holes 2 depends on the coal seam exploitation thickness, the ground subsidence influence degree and the reserved width of the protection coal pillar, and the value of the air inlet hole is generally 20-50 m.
In this embodiment, during gasification, the gas injection device 5 is input into the horizontal directional drilling hole 3 through the gas inlet hole 1, underground gasification of coal is performed through the horizontal directional drilling hole 3, and generated combustible gas is output through the gas outlet hole 2, and more detailed underground gasification steps are described in the method section below.
Compared with the chessboard type gasification furnace in the prior art, the underground coal gasification furnace provided by the embodiment of the invention has the advantages that the overall drilling quantity is obviously reduced, and the single-hole coal exploitation quantity is obviously increased; compared with the drilling through type gasifier in the prior art, the operation of the gas injection device 5 can be directly carried out in the horizontal directional drilling 3, the auxiliary gas inlet hole 1 does not need to be additionally drilled, and the gas injection and gasification process is more convenient.
In this embodiment, further, the underground coal gasifier further includes an auxiliary hole 4, the top end of the auxiliary hole 4 is located on the ground, the bottom end of the auxiliary hole is communicated with the horizontal section 1.2, the auxiliary hole 4 and the vertical section 1.1 are respectively located at two opposite ends of the horizontal section, the auxiliary hole 4 has multiple functions, one auxiliary hole serves as an auxiliary vent hole, such as various waste gases and the like, and is discharged from the auxiliary hole, the second auxiliary hole serves as a target point, in the construction process of the underground coal gasifier, the auxiliary hole 4 is constructed in advance, and other drilling holes are constructed by taking the auxiliary hole 4 as the target point.
In this embodiment, further, a supporting structure is disposed on the horizontal section 1.2 and/or each horizontal directional drilling hole 3, where the supporting structure is a protection structure of the drilling hole, such as a casing, or even a protection structure such as a cement sheath is constructed on the outside of the casing, etc. The supporting structure is used for maintaining the drilling holes and preventing the drilling holes from being deformed and the like under the impact of external factors.
In this embodiment, further, the horizontal section 1.2 is located in the fracture direction or the main stress direction of the coal seam, so that on one hand, the construction difficulty of the horizontal section 1.2 is reduced, and on the other hand, the probability that the horizontal section 1.2 is damaged by the coal seam stress is reduced.
As shown in fig. 1-4, an embodiment of the present invention provides a method for underground gasification of coal, comprising the steps of:
a101, opening an air inlet hole 1, wherein the air inlet hole 1 comprises a vertical section 1.1 and a horizontal section 1.2 which are communicated, the top end of the vertical section 1.1 is positioned on the ground surface, and the horizontal section 1.2 is positioned in a coal seam;
a102, drilling a first exhaust hole 2, wherein the top end of the exhaust hole 2 is positioned on the ground surface, and the bottom end of the exhaust hole 2 is positioned in a coal bed;
a103, drilling a first horizontal directional drilling hole 3, wherein two ends of the horizontal directional drilling hole 3 are respectively communicated with the bottom end of the exhaust hole 2 and the horizontal section 1.2;
specifically, firstly, constructing a vertical section 1.1 from the earth surface to a coal layer, and then horizontally drilling at the bottom of the vertical section 1.1 to construct a horizontal section 1.2. Correspondingly, if the bottoms of the vertical sections 1.1 are connected through inclined pipelines or arc pipelines, the connecting parts are firstly constructed, and then the horizontal sections 1.2 are constructed.
After the air inlet hole 1, a first air outlet hole 2 extending from the ground surface to the coal seam is constructed, and finally, a horizontal section 1.2 which is communicated with the air outlet hole 2 and the air inlet hole 1 is drilled horizontally in the coal seam, so that a first structure capable of carrying out underground gasification is formed.
In this embodiment, in each of the above-mentioned and later-described drilling holes, after the drilling hole is formed, the corresponding construction of the supporting structure can be performed, and the drilling holes and the construction of the supporting structure are all common knowledge and conventional technical means in the art, which are not described in detail in this embodiment.
A104, the gas injection device 5 is arranged in the first horizontal directional drilling hole 3 through the gas inlet hole 1 to carry out underground gasification, and gasified gas is output to the ground surface through the gas outlet hole 2;
specifically, underground coal gasification is performed at the moment, a coal bed discharged from the horizontal directional drilling hole 3 is ignited, a gasification agent is continuously fed into the horizontal directional drilling hole 3 by the gas injection device 5 to react with the coal bed, and coal gas generated in the gasification process is conveyed to the ground through the gas exhaust hole 2.
In this embodiment, since the length of the horizontal directional drilling hole 3 may be long, such as about 300 meters, further, as shown in fig. 3, in the underground gasification process, the horizontal directional drilling hole 3 includes a plurality of gas injection positions G1, G2, G3, etc., and the gas injection device 5 moves from one end near the gas outlet hole 2 to one end near the horizontal directional drilling hole 3, and performs gas injection gasification at each of the gas injection positions. Specifically, the gas injection position is moved to the G1 position for gas injection gasification, after the gasification of the G1 position is completed, for example, after the mining reserve is designed and/or after the content of the effective components and the calorific value of the gas are obviously reduced, the gas injection device 5 cannot be moved to the G2 position for gas injection gasification after the adjustment by changing the technological parameters, and the operations are sequentially performed until the gasification of the first horizontal directional drilling hole 3 is completed. The determination of the gas injection positions and the mutual distance is determined according to different equipment and specific gasification requirements, and one gas injection position is arranged for example 10-30 meters.
And A105, after the first horizontal directional drilling hole 3 is gasified underground, circulating the steps A102-A104 to drill a plurality of exhaust holes 2 and the horizontal directional drilling hole 3, and correspondingly gasifying underground.
Specifically, after gasification is finished, judgment is performed according to specific conditions in the gasification process, such as after the mining reserve is designed and/or when the content of effective components and the heat value of coal gas are obviously reduced, the gasification end can be judged after the adjustment can not be performed by changing technological parameters, so that the second exhaust hole 2 and the second horizontal directional drilling hole 3 are drilled for underground gasification, and the third is performed after the second is finished until the mining of the whole area is finished.
In this embodiment, since the above-mentioned underground coal gasifier has the above-mentioned technical effects, the corresponding underground gasification method of the underground coal gasifier should also have the corresponding technical effects.
As shown in fig. 1, 2, 3 and 6, another embodiment of the present invention provides a method for underground gasification of coal, comprising the steps of:
b101, drilling an air inlet hole 1, wherein the air inlet hole 1 comprises a vertical section 1.1 and a horizontal section 1.2 which are communicated, the top end of the vertical section 1.1 is positioned on the ground surface, and the horizontal section 1.2 is positioned in a coal seam;
b102, drilling a plurality of exhaust holes 2, wherein the top ends of the exhaust holes 2 are positioned on the ground surface, and the bottom ends of the exhaust holes 2 are positioned in a coal bed;
b103, drilling a first horizontal directional drilling hole 3, wherein two ends of the horizontal directional drilling hole 3 are communicated with the bottom end of one of the exhaust holes 2 and the horizontal section 1.2;
104, the gas injection device 5 is arranged in the first horizontal directional drilling hole 3 through the gas inlet hole 1 to carry out underground gasification, and gasified gas is output to the ground surface through the gas outlet hole 2;
and B105, after the underground gasification of the first horizontal directional drilling hole 3 is completed, circulating the steps B103-B104 to drill a plurality of horizontal directional drilling holes 3, wherein each horizontal directional drilling hole 3 corresponds to each exhaust hole 2 one by one, and carrying out underground gasification correspondingly.
Specifically, as different from the gasification method described above, in this embodiment, all the exhaust holes 2 may be drilled in advance, and the horizontal directional drill holes 3 corresponding to the drilling before gasification are communicated with the corresponding exhaust holes 2, so that the exhaust holes 2 may be drilled in a concentrated manner, and the efficiency is high. Obviously, other construction steps, operation steps and achieved beneficial effects can be performed by the previous gasification method.
In the present invention, as an equivalent alternative, the drilling of holes extending from the ground to the coal seam may be performed without dividing the drilling sequence, for example, the first vent hole 2 may be drilled in advance, or the like. Obviously, it can achieve the same technical effect.
As shown in fig. 5, in the present invention, further, before step a101 or B101, the method further includes:
a101', an auxiliary hole 4 is drilled, the top end of the auxiliary hole 4 is positioned on the ground surface, the bottom end position of the auxiliary hole is designed to be communicated with a horizontal section 1.2 which is drilled later, and the auxiliary hole 4 and the vertical section 1.1 are respectively arranged at two opposite ends of the horizontal section 1.2.
Specifically, the top of auxiliary hole 4 is located the earth's surface, the bottom with horizontal segment 1.2 is linked together, auxiliary hole 4 with vertical segment 1.1 divides to be arranged in the relative both ends of horizontal segment 1.2, auxiliary hole 4 has a plurality of effects, and one of them is as supplementary air vent, like various waste gas etc. is discharged from this department, and second it can be as the target point, in the coal underground gasifier construction process, in advance construction auxiliary hole 4, and then uses auxiliary hole 4 as the target point construction other drilling.
As shown in fig. 5, in the present invention, further, step a105 or B105 further includes:
and A106, plugging the corresponding exhaust hole 2 and/or the horizontal directional drilling hole 3 after underground gasification is finished.
Specifically, after the exploitation of the corresponding horizontal directional drilling hole 3 is completed, the gas injection device 5 is lifted out of the horizontal directional drilling hole 3; and then the horizontal directional drilling hole 3 is plugged by grouting, wherein the horizontal directional drilling hole 3 can plug two parts, namely a connecting channel for sealing the exhaust hole 2 and the combustion area, such as a connecting part of the exhaust hole 2 and the horizontal directional drilling hole 3, and a connecting channel for sealing the horizontal section 1.2 and the combustion area, such as a connecting part of the horizontal section 1.2 and the horizontal directional drilling hole 3, so that gas in the combustion area is prevented from overflowing the ground or entering the horizontal section 1.2 to form negative influence on coal exploitation in other areas.
Furthermore, during the plugging operation, a protective gas is input through the air inlet hole 1 to ventilate and protect the plugging position. Such as by injecting nitrogen into the annulus of the inlet port 1 for replacement and venting protection, and venting through the auxiliary port 4.
In the present invention, as a more detailed implementation of the band parameters, two examples are provided as follows:
the method comprises the following steps:
the structure of the gasification furnace is shown in figures 1 and 2, and an auxiliary hole C1 is constructed in the coal seam from the ground; constructing an air inlet hole D1 at a position about 300m away from the C1 by taking the auxiliary hole C1 as a target point, wherein a horizontal section 2S of the air inlet hole is positioned in the coal seam, the tail end of the horizontal section is communicated with the bottom of the auxiliary hole C1, the length is about 150m, and the horizontal section 2S is along the main fracture direction or the maximum main stress direction of the coal seam; and 6 exhaust holes are respectively constructed along two sides of the horizontal section 2S of the air inlet D1, and the distance between the exhaust holes is 25m, wherein the exhaust holes are A1 to A6 and B1 to B6 respectively.
By one of them exhaust hole, if A1, carry out horizontal directional drilling construction to inlet port D2 horizontal segment 2S design position (can set up the target point) S1, horizontal directional drilling is 45 with the contained angle between the horizontal segment, and the horizontal section 2S intercommunication of inlet port is with exhaust hole A1 to construction horizontal directional drilling E1, and horizontal directional drilling E1' S length is about 100m.
The gas injection device 5 is lowered from the gas inlet hole D1 and guided into the horizontal directional drilling hole E1 communicated with the gas outlet hole A1, the initial gas injection position G1 is selected to be close to the bottom end of the hole of the gas outlet hole A1, the distance is about 15m, the coal bed is ignited at the initial gas injection position G1, gasifying agent is continuously fed through the gas injection device 5 to react with the coal bed, and coal gas generated in the gasification process is conveyed to the ground through the gas outlet hole A1.
After the coal bed at the initial gas injection position G1 reaches the designed exploitation reserve and/or when the content of the effective components and the heat value of the gas are obviously reduced, the gasification agent injection position G2 is changed by the backward movement gas injection device 5 and the backward distance is 8m after the adjustment cannot be carried out by changing the technological parameters, so that the combustion area is guided to move to form a new gasification working surface, and the continuity of the gas production process and the gas quality are maintained. And continuously backing the gas injection points to G3 and G4 … … according to the mode until the coal seam between the gas exhaust hole A1 and the horizontal section S1 is gasified and mined, wherein the backing distance is 6-8 m each time.
After coal seam gasification exploitation between the exhaust hole A1 and the horizontal section S1 is completed, the gas injection device 5 is lifted out from the gas inlet hole D1; and then grouting to plug the joint between the vent hole A1 and the horizontal section S1 which are subjected to gasification exploitation, so as to form a cement plug 7 to complete the plugging. In the operation process, nitrogen is injected into the annular space of the air inlet hole D1 for replacement and ventilation protection, and the air is discharged through the auxiliary hole C1.
Performing horizontal directional drilling construction on the new exhaust hole B1 according to the method, wherein the included angle between the direction of the horizontal well F1 and the horizontal section 2S is 45 degrees at the position of the set position S1 of the connecting exhaust hole B1 and the horizontal section, and the horizontal directional drilling length is 100m; continuously injecting gas through the gas injection device 5 to finish gasification exploitation of the section of coal seam; and plugging the drill hole connection where the gasification exploitation is completed.
Continuously completing the gasification exploitation of the coal seam between the exhaust holes A2 and B2 and the horizontal segment set position S2; repeating the steps until the gasification exploitation of the coal seam between each exhaust hole and the horizontal section in the coverage area of the gasification furnace is completed.
And two,:
the structure of the gasification furnace is shown in figures 1 and 2, and an auxiliary hole C1 is constructed in the coal seam from the ground; constructing an air inlet hole D1 at a position about 500m away from the C1 by taking the auxiliary hole C1 as a target point, wherein a horizontal section 2S of the air inlet hole is positioned in the coal seam, the tail end of the horizontal section is communicated with the bottom of the auxiliary hole C1, the length is about 300m, and the horizontal section 2S is along the main fracture direction or the maximum main stress direction of the coal seam; 10 exhaust holes are respectively constructed along two sides of the horizontal section 2S of the air inlet D1, the exhaust holes are respectively A1-A10 and B1-B10, and the space between the vertical drilling holes is 30m.
One of the exhaust holes, such as A1, is used for carrying out horizontal directional drilling construction on a design position (a target point can be arranged) S1 of a horizontal section 2S of the air inlet hole D2, the included angle between the azimuth of a horizontal well and the horizontal section is 30 degrees, and a horizontal directional drilling E1 is constructed to communicate the exhaust hole A1 with the horizontal section 2S of the air inlet hole, and the length of the horizontal directional drilling E1 is about 200m.
The gas injection device 5 is lowered from the gas inlet hole D1 and guided into the horizontal directional drilling hole E1 communicated with the gas outlet hole A1, the initial gas injection position G1 is selected to be close to the bottom end of the hole of the gas outlet hole A1, the distance is about 10m, the coal bed is ignited at the initial gas injection position G1, gasifying agent is continuously fed through the gas injection device 5 to react with the coal bed, and coal gas generated in the gasification process is conveyed to the ground through the gas outlet hole A1.
After the coal bed at the initial gas injection position G1 reaches the designed exploitation reserve and/or when the content of the effective components and the heat value of the gas are obviously reduced, the gasification agent injection position G2 is changed and the retreating distance is 15m through the retreating mobile gas injection device 5 after the adjustment cannot be carried out by changing the technological parameters, so that the combustion area is guided to move to form a new gasification working surface, and the continuity and the gas quality of the gas production process are maintained. And continuously backing the gas injection points to G3 and G4 … … according to the mode until the coal seam between the gas exhaust hole A1 and the horizontal section S1 is gasified and mined, wherein the backing distance is 15-20 m each time.
After coal seam gasification exploitation between the exhaust hole A1 and the horizontal section S1 is completed, the gas injection device 5 is lifted out from the gas inlet hole D1; and then grouting to plug the joint between the vent hole A1 and the horizontal section S1 which are subjected to gasification exploitation, so as to form a cement plug 7 to complete the plugging. In the operation process, nitrogen is injected into the annular space of the air inlet hole D1 for replacement and ventilation protection, and the air is discharged through the auxiliary hole C1.
Performing horizontal directional drilling construction on the new exhaust hole B1 according to the method, wherein the included angle between the direction of the horizontal well F1 and the horizontal section 2S is 30 degrees at the position of the set position S1 of the connecting exhaust hole B1 and the horizontal section, and the horizontal directional drilling length is 200m; continuously injecting gas through the gas injection device 5 to finish gasification exploitation of the section of coal seam; and plugging the drill hole connection where the gasification exploitation is completed.
Continuously completing the gasification exploitation of the coal seam between the exhaust holes A2 and B2 and the horizontal segment set position S2; repeating the steps until the gasification exploitation of the coal seam between each exhaust hole and the horizontal section in the coverage area of the gasification furnace is completed.
While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that modifications may be made to the described embodiments in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive of the scope of the invention, which is defined by the appended claims.
Claims (3)
1. An underground coal gasifier, comprising:
the air inlet comprises a vertical section and a horizontal section which are communicated, the top end of the vertical section is positioned on the ground surface, and the horizontal section is positioned in the coal seam;
the top end of each vent hole is positioned on the ground surface, and the bottom end of each vent hole is positioned in the coal seam;
the horizontal directional drilling holes are in one-to-one correspondence with the exhaust holes, and two ends of each horizontal directional drilling hole are respectively communicated with the bottom ends of the exhaust holes and the horizontal section;
further comprises:
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, and the auxiliary hole and the vertical section are respectively arranged at the opposite ends of the horizontal section;
the angle between the horizontal directional drilling and the part, which is far away from the vertical section, of the horizontal section is between 15 and 90 degrees;
the underground coal gasification method based on the underground coal gasification furnace comprises the following steps:
the drilling device comprises a drill hole, a drill hole and a drill hole, wherein the drill hole comprises a vertical section and a horizontal section which are communicated, the top end of the vertical section is positioned on the ground surface, and the horizontal section is positioned in a coal seam;
drilling a first vent hole, wherein the top end of the vent hole is positioned on the ground surface, and the bottom end of the vent hole is positioned in the coal bed;
a first horizontal directional drilling hole is drilled, and two ends of the horizontal directional drilling hole are respectively communicated with the bottom end of the exhaust hole and the horizontal section;
the gas injection device is downwards arranged into the first horizontal directional drilling hole through the gas inlet hole to carry out underground gasification, and gasified gas is output to the ground surface through the gas outlet hole;
after the underground gasification of the first horizontal directional drilling hole is completed, the steps are circulated to drill a plurality of vent holes and horizontal directional drilling holes, and the underground gasification is correspondingly carried out;
the drilling of the first vent hole further comprises:
drilling an auxiliary hole, wherein the top end of the auxiliary hole is positioned on the ground surface, the bottom end of the auxiliary hole is designed to be communicated with a horizontal section which is subsequently drilled, and the auxiliary hole and the vertical section are respectively arranged at two opposite ends of the horizontal section;
in the step of carrying out underground gasification by entering an air injection device into a first horizontal directional drilling hole through the air inlet hole, the horizontal directional drilling hole comprises a plurality of air injection positions, the air injection device moves from one end close to the air outlet hole to one end close to the horizontal directional drilling hole, and air injection gasification is carried out at each air injection position;
the step of underground gasifying by entering the gas injection device into the first horizontal directional drilling hole through the gas inlet hole further comprises the following steps:
plugging the corresponding exhaust hole and/or the horizontal directional drilling hole after underground gasification is finished;
during the plugging operation, protective gas is input through the air inlet hole to carry out ventilation protection on the plugging position.
2. The underground coal gasifier of claim 1, wherein the plurality of vent holes are divided into two rows, the two rows of vent holes being disposed on opposite sides of the horizontal section.
3. The underground coal gasifier of claim 1, wherein the horizontal section is 150-1500 meters away and the horizontal directional drilling is 100-300 meters away;
the horizontal section and/or each horizontal directional drilling hole is provided with a supporting structure;
the horizontal segment is located in a fracture direction or a main stress direction of the coal seam.
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| CN109025951B (en) * | 2018-10-19 | 2024-01-02 | 国氢能源科技有限公司 | Underground gasifier type and building and gasification method |
| CN112761612A (en) * | 2021-01-07 | 2021-05-07 | 中国煤炭地质总局勘查研究总院 | Method for underground coal gasification by using waste coal bed gas well |
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