阅读说明：本技术 一种疏通煤层瓦斯抽采钻孔孔隙和裂隙的装置及方法 (Device and method for dredging pores and cracks of coal seam gas extraction drill hole ) 是由 *** 徐伟杰 李庆源 王晓军 李研 李寿山 于 2020-07-28 设计创作，主要内容包括：本发明涉及瓦斯抽采技术领域,特别是涉及一种疏通煤层瓦斯抽采钻孔孔隙和裂隙的方法及装置；所述装置包括与钻孔连通的负压管和正压管,所述负压管通过第一连接管连接所述钻孔,所述第一连接管上安装有计量单元和第一阀门,所述计量单元用于检测瓦斯流量和压力,所述正压管通过第二连接管连接所述钻孔,所述第二连接管上安装有第二阀门,所述钻孔互相连通；所述方法包括步骤S1,安装；步骤S2,初始化；步骤S3,负压疏通；步骤S4,当采用步骤S3负压疏通无法进行疏通且所述计量单元检测的瓦斯流量Q≤第一设定值时,再采用正压疏通；疏通煤体瓦斯运移过程中的孔隙和裂隙通道、提高钻孔的抽采效率、增加瓦斯抽采量。(The invention relates to the technical field of gas extraction, in particular to a method and a device for dredging pores and cracks of a coal seam gas extraction drill hole; the device comprises a negative pressure pipe and a positive pressure pipe which are communicated with a drill hole, wherein the negative pressure pipe is connected with the drill hole through a first connecting pipe, a metering unit and a first valve are installed on the first connecting pipe, the metering unit is used for detecting the flow and the pressure of gas, the positive pressure pipe is connected with the drill hole through a second connecting pipe, a second valve is installed on the second connecting pipe, and the drill holes are communicated with one another; the method comprises step S1, installing; step S2, initialization; step S3, negative pressure dredging; step S4, when the negative pressure dredging in step S3 cannot be conducted and the gas flow Q detected by the metering unit is not more than a first set value, positive pressure dredging is conducted; the pore and the fracture channel in the coal gas migration process are dredged, the extraction efficiency of the drill hole is improved, and the gas extraction quantity is increased.)

1. The utility model provides a mediation coal seam gas drainage drilling hole and device of crack, its characterized in that includes negative pressure pipe (1) and positive pressure pipe (2) with the drilling intercommunication, negative pressure pipe (1) is connected through first connecting pipe (3) drilling, install metering unit (7) and first valve (5) on first connecting pipe (3), metering unit (7) are used for detecting gas flow and pressure, positive pressure pipe (2) are connected through second connecting pipe (4) drilling, install second valve (6) on second connecting pipe (4), drilling intercommunication each other.

2. The device for dredging coal seam gas extraction borehole pores and cracks according to claim 1, wherein the first valve (5) and the second valve (6) are both mining electric valves, the metering unit (7), the first valve (5) and the second valve (6) are connected with a substation, and the substation is connected with a monitoring host.

3. The device for dredging coal seam gas extraction borehole pores and fractures according to claim 1, wherein the metering unit (7) adopts a combined sensor GD 3.

4. A method for dredging coal seam gas extraction drill hole holes and cracks is characterized by comprising the following steps:

step S1, install: communicating a drill hole with a negative pressure pipe (1) and a positive pressure pipe (2), installing a metering unit (7) and a first valve (5) between the drill hole and the negative pressure pipe (1), and installing a second valve (6) between the drill hole and the positive pressure pipe (2);

step S2, initializing: -the second valve (6) is closed, the metering unit (7) and the first valve (5) are opened;

step S3, negative pressure dredging: when the metering unit (7) detects that the gas flow Q is smaller than or equal to a first set value, the first valve (5) is closed, and the blockages of coal seam gas extraction drill hole holes and cracks are dredged under the action of forward pressure until the pressure P detected by the metering unit (7) rises from a second set value to a value larger than or equal to a third set value, the drill hole is dredged, and the first valve (5) is opened for gas extraction;

and S4, when the negative pressure dredging in the step S3 cannot be conducted and the gas flow Q detected by the metering unit (7) is less than or equal to a first set value, the positive pressure dredging is conducted again: the first valve (5) is closed, the second valve (6) is opened, the blockage of the coal bed gas extraction drill hole and the crack is dredged under the action of reverse pressure, the drill hole is dredged until the pressure detected by the metering unit (7) is larger than or equal to a third set value, and the first valve (5) is opened for gas extraction.

5. The method for dredging coal seam gas extraction borehole pores and fractures according to claim 4, wherein in the step S1, the borehole is connected with the negative pressure pipe (1) through a first connecting pipe (3), and the borehole is connected with the positive pressure pipe (2) through a second connecting pipe (6).

6. The method for dredging coal seam gas extraction borehole pores and fractures according to claim 4 or 5, wherein the first set value in step S3 or S4 is L/100K, wherein L is the borehole length and is measured in meters, and K is the minimum flow rate of a hundred meters borehole, namely 0.01L/min.

7. The method for dredging coal seam gas extraction borehole pores and fractures according to claim 6, wherein the second set value in step S3 or S4 is-13 KPa.

8. The method for dredging coal seam gas extraction borehole pores and fractures according to claim 7, wherein the third set value in step S3 or S4 is +13 KPa.

9. The method for dredging coal seam gas extraction borehole pores and fractures according to claim 4, wherein the first valve (5) and the second valve (6) are both mining butterfly valves.

10. The method for dredging coal seam gas extraction borehole pores and cracks according to claim 4, wherein the first valve (5) and the second valve (6) are all mining electric valves, the metering unit (7), the first valve (5) and the second valve (6) are connected with a substation, and the substation is connected with a monitoring host.

Technical Field

The invention relates to the technical field of gas extraction, in particular to a method and a device for dredging pores and cracks of a coal seam gas extraction drill hole.

Background

Coal is a very heterogeneous organic rock transformed from plant remains, and plant cell structures are preserved to varying degrees. The difference of the original cell structure of the plant and the integrity of the preservation of the plant are different, and the colloidal substances in the early stage of coal formation gradually dehydrate and coagulate to form countless tiny holes in long geological age due to the action of high temperature and high pressure. The classification according to the pores in coal is as follows:

1. micropores, the diameter of which is less than 0.01 μm, which constitute the adsorption volume in the coal;

2. the diameter of the small hole is 0.1-0.1 mu m, and the small hole forms a capillary condensation space and a gas diffusion space;

3. the diameter of the mesopore is 0.1-1 mu m, and the mesopore forms a slow laminar flow permeation area;

4. the diameter of the macropores is 1-100 mu m, and the macropores can change the original pores and generate new pores in the coal deterioration process.

5. Pores and fissures are visible, with a diameter greater than 100 μm, which constitute the zone of mixed permeation of laminar and turbulent flows and determine the macroscopic destruction surface of the coal.

Heterogeneity in the coal bed is not only expressed by the development of various pores and the damage types of the coal body, but also different physical and mechanical properties and characteristics of the coal due to different damage degrees; the categories of coal feature formation, including coal gloss, structural features, joint face properties, strength, fracture properties, manifest as the general development of fractures, and thus coal is a porous substance. Coal seams are accompanied by the formation of a certain amount of gas during coal formation, which is mainly stored in pores and fissures of the coal seams, and the diffusion and migration of the gas also take place in the pores and fissures. Pores and fissures in coal seams are both sites for gas storage and important pathways for gas production. The channels are changed continuously, and the holes and cracks in the process of extracting and transporting the mine borehole gas below 13Kp for a long time (required by the coal industry standard) cause plugging, so that the extraction amount of the borehole is seriously influenced, and therefore, the method for dredging the holes and cracks of the coal seam gas extraction borehole and increasing the gas extraction amount is provided.

Analyzing the reason for plugging caused by pores and cracks in the gas migration process in the gas extraction drill hole: heterogeneity within the coal seam, and the physical and mechanical properties of coal due to their different degrees of destruction, manifest as the development of various pores. The gas in the coal seam drill hole is extracted at 13Kp for a long time (required by the coal industry standard), and the gas in the coal seam drill hole is blocked to cause holes and cracks in the gas migration process, so that the gas extraction amount of the coal seam drill hole is influenced.

Disclosure of Invention

The invention aims to provide a method for dredging coal seam gas extraction drill hole and fracture, which adopts methods based on negative pressure pipe dredging and positive pressure pipe dredging to dredge the coal seam gas extraction drill hole and fracture for gas extraction, improves the gas extraction efficiency and increases the gas extraction amount.

In order to solve the technical problems, the invention provides the following technical scheme:

the utility model provides a mediation coal seam gas drainage drilling hole and device of crack, includes negative pressure pipe and the positive pressure pipe with the drilling intercommunication, the negative pressure pipe is connected through first connecting pipe drilling, install metering unit and first valve on the first connecting pipe, metering unit is used for detecting gas flow and pressure, the positive pressure pipe is connected through the second connecting pipe drilling, install the second valve on the second connecting pipe, drilling intercommunication each other.

Preferably, the first valve and the second valve are both mining electric valves, the metering unit, the first valve and the second valve are connected with a substation, and the substation is connected with the monitoring host.

Preferably, the metering unit employs a combination sensor GD 3.

A method for dredging coal seam gas extraction drill hole holes and cracks comprises the following steps:

step S1, install: communicating a drill hole with a negative pressure pipe and a positive pressure pipe, installing a metering unit and a first valve between the drill hole and the negative pressure pipe, and installing a second valve between the drill hole and the positive pressure pipe;

step S2, initializing: closing the second valve and opening the metering unit and the first valve;

step S3, negative pressure dredging: when the metering unit detects that the gas flow Q is smaller than or equal to a first set value, the first valve is closed, and the blockages of the holes and cracks of the coal seam gas extraction drill hole are dredged under the action of forward pressure until the pressure P detected by the metering unit rises to be larger than or equal to a third set value from a second set value, the drill hole is dredged, and the first valve is opened for gas extraction;

step S4, when the negative pressure dredging in step S3 cannot be conducted and the gas flow Q detected by the metering unit is not more than a first set value, the positive pressure dredging is conducted again: the first valve is closed, the second valve is opened, the blockage of the coal seam gas extraction drill hole and the fracture is dredged under the action of reverse pressure, the drill hole is dredged until the pressure detected by the metering unit is larger than or equal to a third set value, and the first valve is opened for gas extraction.

Preferably, the bore hole is connected to the negative pressure pipe through a first connection pipe and the bore hole is connected to the positive pressure pipe through a second connection pipe in step S1.

Preferably, the first set value in step S3 or S4 is L/100 × K, where L is the borehole length in meters and K is the minimum flowrate of a hundred meters borehole, i.e. 0.01L/min.

Preferably, the second set value in step S3 or S4 is-13 KPa.

Preferably, the third set value in step S3 or S4 is +13 KPa.

Preferably, the first valve and the second valve are both mining butterfly valves.

Preferably, the first valve and the second valve are both mining electric valves, the metering unit, the first valve and the second valve are connected with a substation, and the substation is connected with the monitoring host.

Compared with the prior art, the technical scheme has the following advantages:

according to the device and the method for dredging the pores and the cracks of the coal bed gas extraction drill hole, provided by the invention, the method based on negative pressure pipe dredging and the method based on positive pressure pipe dredging are similar to a long-period piston motion, and the circulation is repeated in such a way, so that the pores and the crack channels in the coal gas migration process are dredged, the extraction efficiency of the drill hole is improved, and the gas extraction quantity is increased.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a device for dredging coal seam gas extraction borehole pores and fractures provided by the invention.

In the figure: 1. a negative pressure tube; 2. a positive pressure pipe; 3. a first connecting pipe; 4. a second connecting pipe; 5. a first valve; 6. a second valve; 7. a metering unit.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, specific details are set forth in order to provide a thorough understanding of the present invention. The invention can be implemented in a number of ways different from those described herein and similar generalizations can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.