Technique for extracting gas from L-shaped ground drilling well in mining area

Abstract

The invention relates to a coal mine gas extracting technique, in particular to a technique for extracting gas from an L-shaped ground drilling well in a mining area. The technical problems of difficulty in realizing high-efficient gas extraction in the mining area are solved. The technique comprises the following steps: constructing a coal bed gas extracting well on a position away from the mining area; adopting a three-opening directional drilling technique on the ground drilling well; drilling along the direction from a main haulage roadway to an open-off position according to a three-opening hole sequence, wherein a third opening hole is horizontally formed in a rock stratum above a coal bed; connecting a ground wellhead to the inside of an independent extracting pump station. Before the underground coal back-extraction, a construction penetrating layer drilling hole is communicated with the third opening hole; during a back-extraction process, gas passes through the penetrating layer drilling hole and swarms into the three-opening hole, a ground extracting pump station is started for extracting the gas, a back-extraction surface is continuously advanced, a top layer falls, and then the three-opening hole is subjected to rock shift, so that the shearing is formed and the three-opening hole is gradually extruded and damaged; comprehensively, the ground drilling till key layer completing is adopted by the technique, a high-pumping lane is replaced for pumping and back-extracting the gas on a work surface, the construction period is short, and the desired result is quickly achieved.

Description

technical field [0001] The invention relates to a coal mine gas drainage technology, in particular to a gas drainage technology of drilling an L-shaped well on the ground in a mining area. Background technique [0002] Coalbed methane is commonly known as "gas", and its main component is CH4 (methane). It is an unconventional natural gas associated with coal and stored in coal seams in an adsorbed state. The main component is methane. is good fuel. When the air concentration of coalbed methane reaches a certain value, it will explode when it encounters an open flame, which is the root cause of coal mine gas explosion accidents. Therefore, controlling coalbed methane is an important means to reduce accidents. Coalbed methane is directly discharged into the atmosphere, which is very destructive to the atmosphere. Therefore, if coalbed methane is exploited before coal mining, the coal mine gas explosion rate will be reduced by 70% to 85%. Coalbed methane can be used as clea...

AI Technical Summary

Problems solved by technology

However, in actual production, it is found that the vertical well drainage in the mining area is small, the number of construction wells is large, the investment is large, and the connection requirements are strict, so it is impossible to achieve efficient extraction of coalbed methane

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