CN102680187A - Method and equipment for checking sealing quality of gas extraction drilled holes - Google Patents

Abstract

A method and equipment for inspecting the sealing quality of gas drainage boreholes, which belong to the method and equipment for inspecting the sealing quality of boreholes. Connect the compressed air system with the drainage pipe in the sealed gas drainage borehole through the inspection equipment of the gas drainage borehole, The hole is filled with gas with an initial pressure of 0.2MPa-0.4MPa and an initial flow rate of not less than 20m ³ /h. When the readings of the flow meter and the second pressure gauge are stable for no less than 2 minutes, it means that the gas has entered and exited the gas drainage borehole. The gas is in dynamic equilibrium, that is, the pressure difference inside and outside the borehole sealing section has been determined. If the displayed value of the second pressure gauge is greater than or equal to 0.05MPa, the sealing quality of the gas drainage borehole is qualified. The method and equipment are simple, and it only takes 10 minutes to 15 minutes to test the sealing quality of a gas drainage borehole. The operation is convenient, fast and efficient, and the sealing structure of the borehole is not damaged, so it has wide practicability.

Description

A method and equipment for testing the sealing quality of gas drainage boreholes

technical field

The invention relates to a method and equipment for inspecting the sealing quality of boreholes, in particular to a method and equipment for inspecting the sealing quality of gas drainage boreholes.

Background technique

The sealing quality of gas drainage borehole is the key to ensure the effect of gas drainage. At present, there are still some problems in the sealing quality of drainage boreholes in our country, and the lack of effective inspection methods is one of the important reasons. The sealing quality of the drainage borehole is judged by the gas concentration during the extraction process, that is, the rate at which the gas concentration decays is judged. Generally, the gas concentration needs to be continuously observed for about 30 days. The inspection period is long, and it is an after-the-fact judgment. It is difficult to improve the borehole sealing in time quality or method. After about 30 days of observation, if it is found that the sealing quality of the gas drainage borehole is poor, and the gas drainage rate of the coal body cannot meet the "Interim Regulations on Coal Mine Gas Drainage Standards" formulated by the National Development and Reform Commission and other organizations, the coal mine cannot To carry out coal mining operations in this area, it is necessary to drill gas drainage boreholes for gas drainage in areas that do not meet the standards, or to seal or reseal existing gas drainage boreholes to improve the sealing quality of boreholes and gas drainage amount until the gas extraction reaches the standard. This wastes a lot of manpower, financial resources and material resources, which has seriously affected the coal production and economic benefits of coal mining enterprises.

At present, the methods of "through-hole coring" and "layer-by-layer sampling" are often used in geology to test the sealing quality of boreholes. The "through-hole coring" method can completely reveal the true face of the borehole seal, and accurately reflect the position and strength of the borehole seal, but it is time-consuming, laborious, expensive, and at the same time destroys the original sealed borehole itself. Reseal the remedy. The "layer-by-layer sampling" method only takes samples from the upper part of the borehole sealing section, which is very representative for reflecting the sealing quality of the upper part of the drilling sealing section, but cannot reflect the sealing quality of the lower part of the sealing section.

Contents of the invention

The purpose of the present invention overcomes the deficiencies in the prior art, provides a method and equipment for quickly inspecting the sealing quality of gas drainage boreholes with simple method and compact equipment, and solves the problem of difficult inspection of the sealing quality of gas drainage boreholes in coal mines.

The present invention is a kind of method for checking the sealing quality of gas drainage borehole, comprising the following steps:

a. Pass the compressed air system through the first control valve, the pipeline equipped with the first pressure gauge, the second control valve, the flow meter, the three-way pipe and the second pressure gauge, and the drainage pipe in the sealed gas drainage borehole connected, and the exhaust valve is installed on the tee pipe;

b. Close the second control valve and exhaust valve, open the first control valve, so that the first pressure indication is within the range of 0.2MPa～0.4MPa;

c. Open the second control valve, so that the gas in the compressed air system of the coal mine is filled into the gas drainage borehole through the pipeline and the extraction pipe;

d. When the indications of the flowmeter and the second pressure gauge are stable for no less than 2 minutes, and the indication value of the second pressure gauge is greater than or equal to 0.05MPa, the sealing quality of the gas drainage borehole is qualified;

e. Close the first control valve, open the exhaust valve, and remove the pipeline after the second pressure indicator drops to zero.

The initial flow rate of the compressed air system charging gas into the gas drainage borehole is not less than 20 m ³ /h.

The equipment for testing the sealing quality of gas drainage boreholes of the present invention includes: pipelines, a first pressure gauge, a second control valve, a flow meter, a three-way pipe, an exhaust valve and a second pressure gauge;

The second control valve is connected to the first control valve through a pipeline, the first pressure gauge is connected to the pipeline, the flow meter is connected between the second control valve and the three-way pipe, and one end of the three-way pipe is connected to the exhaust valve. The third end of the three-way pipe is connected with the extraction pipe, and a second pressure gauge is connected on the pipeline between the three-way pipe and the extraction pipe.

Beneficial effects, due to the adoption of the above scheme, a method and equipment for checking the sealing quality of gas drainage boreholes in the present invention fully utilize the existing compressed air system in the coal mine. The gas in the compressed air system has good permeability, can enter the fine cracks around the gas drainage borehole, and leak out through the cracks, which can be used to test whether there are air leakage cracks and air leakage cracks in the sealing section of the gas drainage drilling hole How much, so as to detect the quality of the drilling seal. The reading of the first pressure gauge is within the range of 0.2MPa～0.4MPa, so as to avoid excessive pressure of filling gas into the gas drainage borehole, so as to ensure that the sealing quality of the existing gas drainage borehole is not damaged. The flow meter measures the flow of gas entering the gas extraction borehole, and the second pressure gauge is used to measure the stable pressure inside the borehole. The purpose of opening the exhaust valve is to discharge the gas in the borehole to ensure safety when removing the pipeline. When the readings of the flowmeter and pressure gauge are stable and constant, it means that the gas entering and leaving the borehole is in dynamic balance, that is, the pressure difference inside and outside the sealing section of the borehole has been determined, and the pressure indication directly reflects the sealing quality of the borehole . The method and equipment only need 10-15 minutes to test a gas drainage borehole, which is convenient, fast and efficient, and does not damage the sealing structure of the borehole itself, effectively solving the problem of difficult quality inspection of the gas drainage borehole seal, and has wide application practicality.

Description of drawings

Fig. 1 is a schematic diagram of a method and equipment for checking the sealing quality of a gas drainage borehole according to the present invention.

In the figure: 1. Compressed air system; 2. First control valve; 3. Pipeline; 4. First pressure gauge; 5. Second control valve; 6. Flowmeter; 7. Tee pipe; 8. Exhaust Valve; 9. Second pressure gauge; 10. Sealing section; 11. Drainage pipe; 12. Gas drainage borehole.

Detailed ways

Below in conjunction with accompanying drawing, the example of the present invention will be further described:

The specific method for checking the sealing quality of the gas drainage boreholes of the present invention: arrange the gas drainage boreholes 12 in the underground coal mine where gas drainage is required, and seal the gas drainage boreholes 12 to form a gas drainage process. Sealing section 10 of gas extraction borehole 12 to prevent gas leakage. The compressed air system 1 passes through the first control valve 2, the pipeline 3 provided with the first pressure gauge 4, the second control valve 5, the flow meter 6, the tee pipe 7 and the second pressure gauge 9, and the sealed gas pump. The extraction pipe 11 in the drilling hole 12 is connected, and the three-way pipe 7 is provided with an exhaust valve 8 . Close the second control valve 5 and the exhaust valve 8, open the first control valve 2, make the reading of the first pressure gauge 4 within the range of 0.2MPa ~ 0.4MPa, avoid filling gas pressure into the gas drainage borehole 12 If it is too large, the sealing quality of the existing gas drainage borehole 12 is guaranteed not to be damaged. Open the second control valve 5, so that the gas in the compressed air system 1 is charged into the gas extraction borehole 12 through the pipeline 3 and the extraction pipe 11, and the flow meter 6 measures the flow rate of the gas entering the gas extraction borehole 12, The initial flow rate is required to be not less than 20 m ³ /h. After the gas enters the gas drainage borehole 12, depending on its own permeability, it enters the small cracks around the gas drainage borehole 12 and leaks out through the cracks, which can well test the sealing section 10 of the gas drainage borehole 12 Whether there are air leakage fissures and the number of air leakage fissures, so as to detect the sealing quality of the gas drainage borehole 12 . When the gas entering and leaving the gas drainage borehole 12 is in dynamic balance, that is, when the pressure difference inside and outside the sealing section 10 of the gas drainage borehole 12 has been determined, the indications of the flowmeter 6 and the second pressure gauge 9 are stable for a long time. After 2 minutes, if the indicated value of the second pressure gauge is greater than or equal to 0.05MPa, the sealing quality of the gas drainage borehole is qualified. Close the first control valve 2 and stop filling the gas extraction borehole 12 with gas. Open the exhaust valve 8 to drain the gas in the gas extraction borehole 12 to ensure safety when the pipeline 3 is removed. After the indication of the second pressure gauge 9 drops to zero, the pipeline 3 is removed, and the inspection of the sealing quality of the gas drainage borehole 12 is completed. This method only needs 10 minutes to 15 minutes to test a gas drainage borehole 12, which is convenient, fast and efficient, and does not damage the sealing structure of the gas drainage borehole 12 itself, effectively solving the problem of difficult sealing quality inspection of the gas drainage borehole 12 .

Through long-term practice, it is concluded that when the stable indication value of the second pressure gauge 9 is greater than or equal to 0.15MPa, the gas drainage concentration of the gas drainage borehole 12 can be maintained above 65% for a long time, indicating that the gas drainage borehole 12 is sealed Excellent quality; when the stable indication value of the second pressure gauge 9 is greater than or equal to 0.1MPa and less than 0.15MPa, the gas drainage concentration of the gas drainage borehole 12 can be maintained above 50% for a long time, indicating that the gas drainage borehole The sealing quality of 12 is good; when the stable reading of the second pressure gauge 9 is greater than or equal to 0.05MPa and less than 0.1MPa, the gas drainage concentration of the gas drainage borehole 12 can be maintained above 30% for a long time, indicating that the gas drainage The sealing quality of the borehole 12 is moderate; when the second pressure gauge 9 shows less than 0.05MPa, the gas drainage concentration of the gas drainage borehole 12 drops below 30% after about 20 days of drainage, and the sealing quality of the gas drainage borehole 12 Difference.

A device for testing the sealing quality of gas drainage boreholes includes: a pipeline 3, a first pressure gauge 4, a second control valve 5, a flow meter 6, a tee pipe 7, an exhaust valve 8 and a second pressure gauge 9;

The second control valve 5 is connected to the first control valve 2 through the pipeline 3, and the other end of the first control valve 2 is connected to the compressed air system 1. The first pressure gauge 4 is connected to the pipeline 3, and the second control valve 5 A flow meter 6 is connected between the three-way pipe 7, one end of the three-way pipe 7 is connected with the exhaust valve 8, the third end of the three-way pipe 7 is connected with the extraction pipe 11, and between the three-way pipe 7 and the extraction pipe A second pressure gauge 9 is connected to the pipeline between 11, and the extraction pipe 11 is inserted into the gas extraction borehole 12, and there is a sealing section 10 between the extraction pipe 11 and the gas extraction borehole 12.

The first pressure gauge 4 is used to measure the initial pressure of the compressed air system 1 filling the gas drainage borehole 12, and it is guaranteed to be within the range of 0.2MPa～0.4MPa. The flowmeter 6 measures the flow rate of gas entering the gas extraction borehole 12 to ensure that the initial flow rate is not less than 20 m ³ /h. The second pressure gauge 9 is used to measure the stable pressure value inside the gas drainage borehole 12 and to judge the sealing quality of the gas drainage borehole 12 . The exhaust valve 8 that one end of the tee pipe 7 is provided with is in order to drain the gas in the gas extraction borehole 12 to ensure safety when the pipeline 3 is removed.

Claims (3)

1. method of checking the mash gas pumping drilling airtight quality is characterized in that:

A. with compressed-air system (1) through first operation valve (2), be provided with the pipeline (3) of first tensimeter (4), second operation valve (5), flowmeter (6), three-way pipe (7) and second tensimeter (9) and link to each other with extraction pipe (11) in the mash gas pumping drilling that has sealed (12), go up at three-way pipe (7) vent valve (8) be installed;

B. close second operation valve (5) and vent valve (8), open first operation valve (2), make first tensimeter (4) registration in 0. 2MPa～0.4MPa scope;

C. open second operation valve (5), the gas in the compressed-air system (1) is charged in the mash gas pumping drilling (12) through pipeline (3) and extraction pipe (11);

D. stablize after the duration is no less than 2min when the registration of flowmeter (6) and second tensimeter (9), the registration value of second tensimeter (9) is greater than or equal to 0.05MPa, and then mash gas pumping drilling (12) airtight quality is qualified;

E. close first operation valve (2), open vent valve (8), treat to remove pipeline (3) after second tensimeter (9) registration reduces to zero.

2. a kind of method of checking the mash gas pumping drilling airtight quality according to claim 1 is characterized in that: said compressed-air system (1) is not less than 20 m to the initial flow that mash gas pumping drilling (12) charges into gas ³/ h.

3. realize that aforesaid right requires the equipment of the check mash gas pumping drilling airtight quality of said method for one kind, it is characterized in that: equipment comprises: pipeline (3), first tensimeter (4), second operation valve (5), flowmeter (6), three-way pipe (7), vent valve (8) and second tensimeter (9);

Second operation valve (5) is connected with first operation valve (2) through pipeline (3); On pipeline (3), be connected with first tensimeter (4); Be connected with flowmeter (6) between second operation valve (5) and the three-way pipe (7); One end of three-way pipe (7) is connected with vent valve (8), and the 3rd end of three-way pipe (7) is connected with extraction pipe (11), on the pipeline between three-way pipe (7) and the extraction pipe (11), is connected with second tensimeter (9).

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