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Gas drainage method combining surface and underground fracturing and permeability improvement

A technology of gas drainage and fracturing, which is applied in the field of fracturing and anti-reflection gas drainage, and can solve problems such as low permeability, poor drainage effect, and insufficient capacity of fracturing equipment

Inactive Publication Date: 2012-03-28
HENAN COAL CHEM IND GROUP INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, my country's surface gas drainage technology has only achieved good results in some mining areas such as the Qinshui Basin and the Fuxin Basin in Liaoning. The seam coal is soft and the permeability is low. If no anti-permeability measures are taken, the gas drainage radius of the conventional downhole borehole is small, and the drainage effect is poor. Drainage is carried out at the expense of high engineering investment such as densely distributed holes and coal seam top and bottom slate pumping roadways. Therefore, it is necessary to adopt hydraulic strengthening and anti-permeability measures to transform the coal reservoir and its top and bottom floors
However, when the downhole fracturing equipment is used to fracturing the coal reservoir and its roof and floor through directional long drilling, it often shows that the capacity of the fracturing equipment is insufficient, and the expected reconstruction purpose cannot be achieved.
Using surface coalbed methane development technology to fracturing the coal reservoir and its roof and floor on the ground can achieve the expected effect, but the economic cost is high

Method used

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  • Gas drainage method combining surface and underground fracturing and permeability improvement
  • Gas drainage method combining surface and underground fracturing and permeability improvement
  • Gas drainage method combining surface and underground fracturing and permeability improvement

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Experimental program
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Effect test

Embodiment 1

[0027] Such as figure 2 , 3 , Shown in 4, a kind of method that implements the combination of upper and lower fracturing in a single coal seam roof to increase permeability and extract gas. There is a single coal seam 4 with a thickness of 6m and a burial depth of 120m. The soft layer is located at the bottom of the coal seam 4, and the water content in the coal seam roof 3 is small. Adopting the present invention utilizes a kilometer directional drilling rig in the drilling field 9 to the coal seam roof In 3, an underground large-diameter directional long borehole 6 was constructed, two pressure relief holes 12 were arranged in the coal seam 4, and a ground vertical well 8 was arranged downward on the ground 1, and the vertical well 8 passed through the overlying formation 2 and the Drill field 9 through.

[0028] The specific fracturing extraction steps are as follows:

[0029] (1) Firstly, use a special hole sealing device to seal and solidify a large-diameter directi...

Embodiment 2

[0035] Such as Figure 5 , 6 , 7, a method of implementing combined fracturing and anti-permeability drainage of gas in a single coal seam floor. There is a single coal seam 4 with a thickness of 6m and a burial depth of 120m. The soft layer is located at the top of the coal seam 4, and the water content in the coal seam floor 5 is small. Adopt the present invention to utilize the kilometer directional drilling rig to drill to the coal seam floor in the roadway 9. In 5, an underground large-diameter directional long borehole 6 was constructed, two pressure relief holes 12 were arranged in the coal seam 4, and a ground vertical well 8 was arranged downward on the ground 1, and the vertical well 8 passed through the overlying formation 2 and the The roof of the roadway 9 runs through.

[0036] The specific fracturing extraction steps are as follows:

[0037] (1) Firstly, use a special hole sealing device to seal and solidify a large-diameter directional long borehole 6 in t...

Embodiment 3

[0043] Such as Figure 8 , 9 , 10, a method for gas drainage in a single coal seam that implements combined fracturing up and down the well. There is a single coal seam 4 with a thickness of 6m and a burial depth of 120m. The structural types of the coal are mainly primary structural coal and fragmented coal, and the structural coal is not developed. Adopt the present invention to utilize a kilometer directional drilling machine in the drilling site 9 An underground large-diameter directional long borehole 6 was constructed in the coal seam 4, and two pressure relief holes 12 were arranged in the coal seam 4, and a ground vertical well 8 was arranged downward on the ground 1, and the vertical well 8 passed through the overlying Formation 2 connects with drilling field 9 .

[0044] The specific fracturing extraction steps are as follows:

[0045] (1) Firstly, use a special hole sealing device to seal and solidify a large-diameter directional long borehole 6 in the well, an...

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Abstract

The invention relates to a gas drainage method combining surface and underground fracturing and permeability improvement, and the method comprises the following steps: building underground large-diameter directional long boreholes in a coal reservoir or the top and bottom plates thereof under a coal mine by using a drilling machine; then building pressure relief holes in a coal bed having an appropriate distance with the large-diameter directional long boreholes; building vertical wells communicated with an underground large-diameter directional long borehole filed or nearby roadways thereof from the ground to the underground; firmly connecting large ground fracturing equipment, a ground vertical well shaft and the underground large-diameter directional long boreholes by using high pressure pipelines; carrying out fracturing on each underground large-diameter directional long borehole by using the large ground fracturing equipment to form a three-dimensional fracture network; discharging water in the underground large-diameter directional long boreholes and then carrying out continuous pressure extraction on fracturing holes and the pressure relief holes; and quickly extracting out the coal bed gas through negative pressure by using the three-dimensional fracture network. According to the invention, the coal bed gas can be extracted out quickly with high efficiency by using the three-dimensional fracture network and negative pressure, thereby providing a technical guarantee for safe and high-efficiency production of mines; and the method has the advantage of wide application prospect.

Description

technical field [0001] The invention relates to a method for fracturing and antireflection gas extraction. Specifically, it refers to connecting the ground borehole with the underground borehole, using the ground coalbed methane to develop large-scale fracturing equipment to fracturing the underground coal reservoir and its roof and floor, and proposing a method of combined upper and lower fracturing for enhanced permeability drainage . Background technique [0002] Mine gas (coal bed methane) is a "double-edged sword". According to statistics, the geological resources of coalbed methane buried below 2000m in my country are about 36.81 trillion m 3 , ranking third in the world, because of its similar or better properties to natural gas, as a new type of clean energy, it has great development potential; at the same time, coalbed methane is also a strong greenhouse gas, and its greenhouse effect is equal to that of carbon dioxide 21.5 times. However, as a dangerous factor,...

Claims

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Application Information

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IPC IPC(8): E21F7/00E21B43/26E21B7/00
Inventor 马耕李伍成陶云奇苏现波丁建础刘三钧杨程涛王峰
Owner HENAN COAL CHEM IND GROUP INST
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