A method for measuring coalbed methane resources in abandoned mines

Abstract

The present invention belongs to the field of coalbed methane development in abandoned mines, and specifically relates to a method for measuring the amount of coalbed methane resources in abandoned mines. The present invention solves the technical problem of inaccurate measurement of coalbed methane in abandoned mines. The present invention drills a goaf parameter hole above the goaf to test the pressure, concentration and temperature of the coalbed methane in the goaf; calculates the amount of substance n of the goaf gas per unit volume of each goaf according to the ideal gas state equation PV=nRT, and obtains the amount of substance of the coalbed methane in each goaf according to the volume of the goaf, and then obtains the amount of coalbed methane resources in each goaf through conversion; drills a coal pillar (mining area) parameter well between the mining area and the goaf to collect parameters such as gas content, thickness and porosity of the coal seam. Drill parameter holes in the stable area around the goaf to collect parameters such as gas content and thickness of the coal seam. The coalbed methane resources in the goaf, the coalbed methane resources in the mining area and the coalbed methane resources in the stable area are summed up to obtain the coalbed methane resources in the abandoned mine.

Description

Technical Field

[0001] The invention belongs to the field of abandoned mine coalbed methane development, and in particular relates to a method for measuring the amount of abandoned mine coalbed methane resources. Background Art

[0002] In the investigation of the remaining resources of abandoned coalbed methane, the measurement of abandoned coalbed methane has always been a difficult problem to solve. The measurement results of the existing measurement methods are quite different from the actual situation, which leads to misleading subsequent resource assessment and reuse of abandoned coalbed methane. Therefore, in order to more accurately measure the remaining coalbed methane resources in abandoned mines, a new measurement method needs to be designed to facilitate the investigation of the resources of each mine. Summary of the invention

[0003] The invention provides a method for measuring the amount of coal-bed methane resources in abandoned mines in order to solve the current technical problem of inaccurate measurement of coal-bed methane in abandoned mines.

[0004] The present invention is implemented by adopting the following technical scheme: a method for measuring the amount of coalbed methane resources in an abandoned mine, comprising the following steps: (1) firstly, the coordinates of the mine boundary and the goaf area are delineated according to the abandoned mine data, and the goaf area, the mining area, and the stable area are delineated; the mining area line is delineated according to the previous mining data of the area; the area between the periphery of the mining area and the mine boundary is the stable area;

[0005] (2) Calculate the volume of each goaf based on the demarcated boundary and the target coal seam thickness; drill a goaf parameter well above each goaf to test the pressure P and temperature T of the goaf coal seam gas; calculate the amount n of coal seam gas in each goaf based on the ideal gas state equation PV=nRT, and then convert the amount of coal seam gas resources (i.e., coal seam gas volume) in each goaf based on the formula: gas volume = amount of substance n÷gas molar volume; add up the resources of each goaf to obtain the total resources of all goafs;

[0006] (3) Drill parameter wells in the mining area to collect coal seam gas content in the coal pillars of the mining area. Then, the resource volume of the mining area is obtained by the formula: mining area resource volume = block area × coal seam thickness × coal seam apparent density × coal seam gas content. Then, the resource volume of each mining area is added together to obtain the resource volume of all mining areas. The coal seam thickness and coal seam apparent density of the mining area are both known test data of the coal mine.

[0007] (4) Drill parameter wells in the stable area around the goaf to collect the gas content of the coal seam. Then, the resource volume of the stable area is obtained by the formula: stable area resource volume = block area × coal seam thickness × coal seam apparent density × coal seam gas content. Then, the resource volume of each stable area is added together to obtain the coalbed methane resource volume of all stable areas. The thickness and apparent density of the coal seam in the stable area are both known test data of the coal mine.

[0008] (5) The coalbed methane resources in the goaf area, the coalbed methane resources in the mining area, and the coalbed methane resources in the stable area are summed up to get the coalbed methane resources in abandoned mines.

[0009] The method of the present invention can effectively solve the problem of remaining coalbed methane resources in abandoned mines; the measurement and calculation results are closer to the actual situation, and the results are accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of the distribution of goaf areas, mining areas and stable areas described in the present invention.

[0011] Figure 2 Schematic diagram of parameter wells in goaf area, parameter wells in mining area and parameter wells in stable area.

[0012] 1-mine boundary, 2-first goaf, 3-second goaf, 4-third goaf, 5-coal seam, 6-first mining area, 7-second mining area, 8-first stable area, 9-second stable area, 10-third stable area, 11-fourth stable area, 12-parameter well of the first goaf, 13-parameter well of the second goaf, 14-parameter well of the third goaf, 15-parameter well of the first mining area, 16-parameter well of the second mining area, 17-parameter well of the first stable area, 18-parameter well of the second stable area, 19-parameter well of the third stable area, 20-parameter well of the fourth stable area. DETAILED DESCRIPTION

[0013] Combination Figure 1 and 2 As shown, a method for measuring the amount of coalbed methane resources in an abandoned mine, the structure used in the measurement includes a mine boundary 1, a first goaf area 2, a second goaf area 3, a third goaf area 4, a coal seam 5, a first mining area 6, a second mining area 7, a first stable area 8, a second stable area 9, a third stable area 10, a fourth stable area 11, a first goaf area parameter well 12, a second goaf area parameter well 13, a third goaf area parameter well 14, a first mining area parameter well 15, a second mining area parameter well 16, a first stable area parameter well 17, a second stable area parameter well 18, a third stable area parameter well 19, and a fourth stable area parameter well 20; the three goaf areas are arranged in sequence, the mining area surrounds the three goaf areas, the mining area is divided into two areas of roughly equal area, and the area between the mining area and the mine boundary is a stable area;

[0014] (1) First, the coordinates of the mine boundary and the goaf area are delineated based on the abandoned mine data, and the goaf area, mining area, and stable area are delineated; the mining area line is delineated based on the previous mining data in the area; the area between the outer edge of the mining area and the mine boundary is the stable area; the area is calculated based on the boundary of the goaf area; the thickness of the coal seam is obtained based on the mine data; the area of ​​the goaf area, mining area, and stable area can all be determined;

[0015] (2) Calculate the volume of each goaf based on the demarcated boundary and the target coal seam thickness; drill a goaf parameter well above each goaf to test the pressure P and temperature T of the goaf coal seam gas; calculate the amount n of coal seam gas in each goaf based on the ideal gas state equation PV=nRT, and then convert the amount of coal seam gas resources in each goaf based on the formula: gas volume = amount of substance n÷gas molar volume; add up the resources of each goaf to obtain the total resources of all goafs;

[0016] (3) Drill parameter wells in the mining area to collect coal seam gas content in the coal pillars of the mining area. Then, the resource volume of the mining area is obtained by the formula: mining area resource volume = block area × coal seam thickness × coal seam apparent density × coal seam gas content. Then, the resource volume of each mining area is added together to obtain the resource volume of all mining areas. The coal seam thickness and coal seam apparent density of the mining area are both known test data of the coal mine.

[0017] (4) Drill parameter wells in the stable area around the goaf to collect the gas content of the coal seam. Then, the resource volume of the stable area is obtained by the formula: stable area resource volume = block area × coal seam thickness × coal seam apparent density × coal seam gas content. Then, the resource volume of each stable area is added together to obtain the coalbed methane resource volume of all stable areas. The thickness and apparent density of the coal seam in the stable area are both known test data of the coal mine.

[0018] (5) The coalbed methane resources in the goaf area, the coalbed methane resources in the mining area, and the coalbed methane resources in the stable area are summed up to get the coalbed methane resources in abandoned mines.

[0019] The parameter well in the goaf area is a two-opening structure, with one opening of 3111mm and the other opening of 244.5mm casing cementing; the second opening of 215.9mm is drilled to the inside of the goaf for completion.

[0020] The parameter well in the mining area is a two-opening structure, one opening is 3111mm, and the other opening is 244.5mm casing cementing; the second opening is 215.9mm and drilled to the bottom plate of the target coal seam to obtain coal seam parameters; the boundary of the mining area is 50m outside the goaf.

[0021] The well location of the stable zone parameters has a two-opening structure, one opening is 3111mm, and the other opening is 244.5mm casing cementing; the second opening is 215.9mm and drilled to the bottom of the target coal seam to obtain coal seam parameters; the boundary of the stable zone is between the boundary of the goaf and the mine boundary.

[0022] When there are multiple goafs, the mining area parameter well is opened between two adjacent goafs.

[0023] The present invention drills a coal pillar (mining area) parameter well between the mining area and the goaf area to collect coal seam gas content, thickness, porosity and other parameters. Drill parameter holes in the stable area around the goaf area to collect coal seam gas content, thickness, porosity and other parameters. The coal seam gas resources in the goaf area, the coal seam gas resources in the mining area, and the coal seam gas resources in the stable area are summed up to obtain the coal seam gas resources in the abandoned mine.

Claims

1. A method for measuring the amount of coalbed methane resources in abandoned mines, characterized in that: The method includes the following steps: (1) firstly, the coordinates of the mine boundary and the goaf area are delineated based on the data of abandoned mines, and the goaf area, the mining area, and the stable area are delineated; the mining area line is delineated based on the previous mining data of the area; the area between the outer periphery of the mining area and the mine boundary is the stable area; (2) Calculate the volume of each goaf based on the demarcated boundary and the target coal seam thickness; drill a goaf parameter well above each goaf to test the pressure P and temperature T of the coalbed methane in the goaf; calculate the amount n of coalbed methane in each goaf based on the ideal gas state equation PV=nRT, and then convert the amount of coalbed methane resources in each goaf based on the formula: gas volume = amount of substance n÷gas molar volume; Add up the resource volume of each goaf to get the resource volume of all goafs; (3) Drill parameter wells in the mining area to collect coal seam gas content in the coal pillars of the mining area. Then, the resource volume of the mining area is obtained by the formula: mining area resource volume = block area × coal seam thickness × coal seam apparent density × coal seam gas content. Then, the resource volume of each mining area is added together to obtain the resource volume of all mining areas. The thickness and apparent density of coal seams in the mining area are known test data of the coal mine; (4) Drill parameter wells in the stable area around the goaf to collect the gas content of the coal seam; then use the formula: stable area resource = block area × coal seam thickness × coal seam apparent density × coal seam gas content to obtain the resource volume of the stable area; Then add up the resources in each stable area to get the coalbed methane resources in all stable areas; The thickness and apparent density of coal seams in the stable zone are both known test data of coal mines; (5) The coalbed methane resources in the goaf area, the coalbed methane resources in the mining area, and the coalbed methane resources in the stable area are summed up to get the coalbed methane resources in abandoned mines.

2. The method for measuring the amount of coalbed methane resources in an abandoned mine according to claim 1, characterized in that: The parameter well in the goaf area is a two-opening structure, with one opening of 3111mm and the other opening of 244.5mm casing cementing; the second opening of 215.9mm is drilled to the inside of the goaf and completed.

3. The method for measuring the amount of coalbed methane resources in an abandoned mine according to claim 1, characterized in that: The parameter well in the mining area is a two-opening structure, one opening is 3111mm, and the other opening is 244.5mm casing cementing; the second opening is 215.9mm and drilled to the bottom plate of the target coal seam to obtain coal seam parameters; the boundary of the mining area is 50m outside the goaf.

4. The method for measuring the amount of coalbed methane resources in an abandoned mine according to claim 1, characterized in that: The well location of the stable zone parameters has a two-opening structure, one opening is 3111mm, and the other opening is 244.5mm casing cementing; the second opening is 215.9mm and drilled to the bottom of the target coal seam to obtain coal seam parameters; the boundary of the stable zone is between the boundary of the goaf and the mine boundary.

5. A method for measuring the amount of coalbed methane resources in an abandoned mine as claimed in claim 1 or 3, characterized in that: When there are multiple goafs, the mining area parameter well is opened between two adjacent goafs.

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