WO2019105161A1

WO2019105161A1 - Bedding borehole-based gas extraction method capable of avoiding air leakage

Info

Publication number: WO2019105161A1
Application number: PCT/CN2018/112290
Authority: WO
Inventors: 林柏泉; 刘辉辉; 杨威
Original assignee: 中国矿业大学; 徐州博安科技发展有限责任公司
Priority date: 2017-11-28
Filing date: 2018-10-29
Publication date: 2019-06-06
Also published as: CN108104865B; CN108104865A

Abstract

A bedding borehole-based gas extraction method capable of avoiding air leakage, comprising two stages, i.e., building a main gas extraction system and building an auxiliary gas extraction system: firstly, a main gas extraction pipeline (9) is laid inside a roadway (11), bedding extraction boreholes are constructed, the bedding extraction boreholes are sealed, and borehole-based gas extraction pipes are connected to the main gas extraction pipeline to perform gas extraction; and after all the boreholes in the roadway are sealed for extraction, an airtight wall is constructed at an opening of the roadway where the boreholes are constructed, an auxiliary gas extraction pipeline (10) is laid, and the auxiliary gas extraction pipeline (10) is connected to an auxiliary gas pump extraction pipeline to perform auxiliary extraction. The method can effectively resolve the problem of serious air leakage in a bedding borehole-based extraction process, has a simple process, is easy to implement, and can reduce labor costs.

Description

Gas drainage method for bedding drilling and leakage prevention

Technical field

The invention relates to a gas drainage method for a serious air leakage area in a bedding drilling process, belonging to the field of coal mine gas drainage layer drainage.

Background technique

When drilling holes for coal seam gas drainage, the gas concentration (volume percentage) extracted by the theoretically sealed and leak-proof drilling hole should be close to 100%, but in the actual extraction process, due to a large amount of air leaking, The concentration of gas extraction in most mines in China has been below 30% for a long time.

There are two conditions for air leakage in the gas extraction process. One is that there must be a leaking air passage, and the other is that there is a leakage air pressure difference at both ends of the air leakage passage. The existing related technologies all start to block the air leakage passage, but the air leakage passage is developed on the one hand, and on the other hand, there may be changes along with the extraction time. Therefore, in the actual extraction process, although the sealing process of sealing the air leakage channel is carried out, there is still a certain degree of air leakage, and the sealing process for sealing the air leakage channel is generally complicated, the process is cumbersome, and the sealing is prone to occur. The phenomenon of failure, and the cost is higher.

Summary of the invention

In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a method for gas drainage in a bedding borehole, which is simple in process, can reduce air leakage, and can improve gas drainage concentration and gas drainage efficiency. .

The technical solution adopted by the present invention to solve the technical problem thereof comprises the following steps:

a. Establish a main gas drainage system: lay the main gas drainage pipeline in the construction drilling roadway, construct the bedding drilling hole, and insert the drilling gas drainage pipe in the bedding drilling hole. Layer drainage holes are used for sealing, and the gas drainage pipe is connected to the main gas drainage pipeline for gas drainage; b. Auxiliary gas drainage system: all bedding drainage drills in the construction roadway to be constructed After the hole is constructed and sealed, and connected to the main gas drainage pipeline, a closed wall is constructed at the construction of the roadway, and the auxiliary gas drainage pipeline is connected with the auxiliary gas pump drainage pipeline for auxiliary drainage. .

Compared with the prior art, a gas drainage method for the bedding drilling and leakage prevention of the present invention connects the auxiliary gas drainage pipeline with the auxiliary gas pump drainage pipeline for auxiliary extraction, and the auxiliary drainage is negative. Under the action of pressure, the atmospheric pressure in the construction roadway will gradually decrease, and finally reach or approach the negative pressure in the bedding drainage hole. At this time, the air pressure difference between the two ends of the air leakage passage is close to zero during the extraction process. The air leakage is reduced, the problem of serious air leakage during the bedding drilling process is solved, the purpose of improving the gas drainage concentration is achieved, and the process is simple and easy to implement, which can save a lot of labor costs.

DRAWINGS

The invention will now be further described with reference to the drawings and embodiments.

Figure 1 is a schematic view of gas drainage in the present embodiment;

In the picture: 1, the second layer of cement mortar sealing layer, 2, the second sealing wall, 3, the intermediate cavity of the sealing wall, 4, the first layer of cement mortar sealing layer, 5, the first sealing wall, 6, the drill Kongvas pumping pipe, 7, bedding drilling hole, 8, polyurethane sealing bag, 9, main gas drainage pipeline, 10, auxiliary gas drainage pipeline, 11, construction drilling tunnel, 12, powder Material pellet injection tube.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. It is a part of the embodiment of the invention, not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Referring to FIG. 1, a specific implementation manner of a gas drainage method for a bedding borehole gas leakage prevention system comprises two stages. First, a main gas drainage system is established, and an auxiliary gas drainage system is established on the basis of a main gas drainage system. .

When establishing the main gas drainage system, firstly, the main gas drainage pipeline 9 is laid in the construction drilling roadway 11 and connected with the main gas pump drainage pipeline; then the bedding drainage hole 7 is constructed in the coal seam; The bedding drainage hole 7 is sealed with a polyurethane sealing bag 8; the drilling gas drainage pipe 6 is connected to the main gas drainage pipe 9 for gas drainage; all the design drilling holes in the construction drilling roadway 11 are After the construction and sealing are completed and connected to the main gas drainage pipeline 9, the main gas drainage system is completed.

When establishing the auxiliary gas drainage system, first construct the first sealing wall 5 in the roadway of the drilled hole, and the sealing wall adopts the brick-concrete structure; when the height of the wall is 1200mm, the auxiliary gas drainage pipeline 10 is laid. After the wall is constructed, the outer surface of the wall is sprayed to form a first layer of cement mortar sealing layer 4, the thickness of the sealing layer is 100 mm to 200 mm; and the second sealing wall is constructed at a distance of 2 to 4 m from the first sealing wall 5 2, the same brick-concrete structure; the second sealing wall 2 wall height construction to 1200mm, laying the auxiliary gas drainage pipeline 10 and the powder particle injection pipe 12, after the wall construction is completed, the wall outside the wall The surface is sprayed to form a second layer of cement mortar sealing layer 1 with a thickness of 100 mm to 200 mm; finally, the powder particle injection tube 12 is injected into the intermediate cavity 3 of the closed wall to inject high-pressure fly ash to further seal Function; connect the auxiliary pumping pipe with the auxiliary pumping gas pump pipeline for auxiliary pumping, and the auxiliary gas pumping system is established.

In the embodiment of the present invention, under the action of auxiliary suction negative pressure, the atmospheric pressure in the construction roadway 11 will gradually decrease, and finally reach or approach the suction negative pressure in the bedding drainage hole 7 at this time, at this time, the extraction In the process, the air pressure difference between the two ends of the air leakage passage is close to zero, which reduces the air leakage, solves the problem of serious air leakage during the bedding drilling process, and achieves the purpose of increasing the gas drainage concentration.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modifications and equivalent changes made to the above embodiments in accordance with the technical spirit of the present invention fall into the present invention. Within the scope of protection of the invention.

Claims

A method for gas drainage of gas leakage in a bedding layer, characterized in that the method comprises the following steps:

a. Establish a main gas drainage system: lay the main gas drainage pipeline (9) in the construction drilling roadway (11), construct the bedding drainage hole (7), and drill the drilling hole in the bedding layer (7) A bored gas extraction pipe (6) is inserted, a bedding drilling hole (7) is sealed, and a bore gas extraction pipe (6) is connected to the main gas drainage pipe (9). Gas drainage;

b. Auxiliary gas drainage system: All the bedding drainage holes (7) in the drilling roadway (11) to be constructed shall be constructed and sealed, and connected to the main gas drainage pipeline (9) after construction. The drilling tunnel (11) is constructed with a closed wall, and the auxiliary gas drainage pipeline (10) is connected with the auxiliary gas pump drainage pipeline for auxiliary extraction.
The method of claim 1 , wherein the sealing wall adopts a five-layer structure, and firstly constructs a first road on the inner side of the construction drilling roadway (11). Sealing wall (5), laying auxiliary gas drainage pipeline (10), first sealing wall (5) in the first sealing wall (5) wall and the construction drilling roadway (11) inside the wall After the completion of the construction, spray on the outside of the wall to form the first layer of cement mortar sealing layer (4); to construct a second sealing wall (2) at a distance from the outside, in the second sealing wall (2) wall An auxiliary gas drainage pipe (10) is laid in the construction drilling roadway (11) on the inner side of the wall, and a second layer of cement mortar sealing layer is formed by spraying on the outer side of the second sealing wall (2) wall (1) .
The method of claim 2, wherein the second sealing wall (2) wall and the first sealing wall (5) and the second A powder particle injection pipe (12) is laid in the construction drilling roadway (11) between the road sealing wall (2), and the high pressure in the intermediate cavity (3) of the sealing wall is passed through the powder particle injection pipe (12). Inject fly ash.
The method for extracting wind leakage gas from a bedding borehole according to claim 2 or 3, wherein the first sealing wall (5) and the second sealing wall (2) are brick-concrete structures. .
A method for extracting wind leakage and gas leakage according to claim 2 or 3, wherein a second sealing wall is constructed at a distance of 2 to 4 m from the first sealing wall (5) ( 2).
The method for extracting wind leakage gas from a bedding borehole according to claim 2 or 3, wherein the length of the auxiliary gas drainage pipeline (10) in the construction drilling tunnel (11) is 20~ 30m.
A method for extracting wind leakage and gas leakage by a bedding layer according to claim 2 or 3, characterized in that: the first layer of cement mortar sealing layer (4) and the second layer of cement mortar sealing layer (1) The thickness of the sealing layer is 100 to 200 mm.
The method of claim 1 , wherein the bedding drainage hole (7) is sealed by a polyurethane sealing bag (8).