Multi-level cross-mining-area ground drilling well pattern laying method

Abstract

The invention discloses a multi-level cross-mining-area ground drilling well pattern laying method. The multi-level cross-mining-area ground drilling well pattern laying method comprises the following steps that firstly, a horizontal well is drilled at a position above the ground corresponding to a junction H<1> of a mining area uphill coal pillar of a first mining area C<1> in a first stage of a well field and an upper well field boundary coal pillar; meanwhile, a multilateral well is drilled at the position above the ground corresponding to the junction H<3> of a stage coal pillar between the first stage and the second stage and the mining area uphill coal pillar of the mining area C<1> of the first stage, the horizontal well and the horizontal section of the multilateral well are drilled in a middle coal seam, coal bed gas is extracted, after the extraction amount is reduced to 20% of the initial amount, liquid nitrogen permeability increasing and multiple times of repeated extraction are carried out respectively, and extraction is stopped until the amount of the coal bed gas extracted by a horizontal well extraction pipe reaches 3m < 3 > / min. and the arrangement is repeated to the second stage through the multilateral well, and finally a coal bed gas extraction ground drilling well pattern covering the whole well field range is formed. According to the method, the gas extraction problem of dozens of residual mining areas and the whole layer of waste coal in the middle under the multi-level residual mining area crossing condition is solved.

Description

technical field [0001] The invention relates to a method for laying out a multi-level cross-mining area surface drilling well pattern, and belongs to the field of mining area mining technology. Background technique [0002] Due to long-term high-intensity mining, there are a large number of residual mining areas in my country. As a disastrous gas, gas is extremely destructive. In addition, the greenhouse effect caused by gas gas is about 25 to 72 times that of carbon dioxide. Gas in residual mining areas can diffuse into the atmosphere through poorly sealed wellheads or even surface cracks, thereby aggravating the greenhouse effect. At the same time, gas is also a clean and high-quality energy and chemical raw material. As a clean energy, it can "turn waste into treasure", improve my country's energy structure, and prevent gas from escaping into the atmosphere to increase the greenhouse effect. [0003] At present, the drainage of gas in the old empty area is mainly for th...

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Problems solved by technology

[0005] The present invention aims to provide a multi-level cross-mining area surface drilling well pattern layout method, starting from the maximization of the development and utilization of coal bed methane resources and considering the cost, a method for cooperative extraction of coal bed methane in multi-level old empty areas is proposed. Solved the problem of coordinated extraction of coalbed methane in the upper and lower parts of multiple old empty areas and the whole layer of abandoned coal in the middle

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