Well structure and well-free type coal underground gasification ignition system and method applying well structure

Abstract

The invention relates to a well structure and a well-free type coal underground gasification ignition system and method applying the well structure. The method comprises the three steps that 1, two horizontal wells with the horizontal section distance of about 1.5 m are dug in an underground coal seam on the ground, and the two horizontal wells can move oppositely or in parallel; 2, a perforating device is conveyed to a preset horizontal section coal seam of one horizontal well (such as the first horizontal well) through a continuous oil pipe or an oil pipe to perform directional perforation in the direction of the second horizontal well, and communication in two shafts is formed; and 3, an ignition device is conveyed to the coal seam position of the first horizontal well with the through hole, the ignition device is ignited through electrification, long-time high-temperature flames are generated, meanwhile, a large amount of oxygen is input into the first horizontal well from a ground oxygen supply station, the coal seam is ignited to form an underground coal gasification furnace, and generated mixed gas is output outwards from the shaft of the second horizontal well. Compared with other existing modes, the method has the advantages that rapid and reliable ignition and combustion can be carried out at any position of the coal seam, a larger underground gasification furnace is formed, and more combustion gas is generated.

Description

technical field [0001] The invention belongs to the field of underground coal gasification, and in particular relates to a shaft structure and an ignition system and method for wellless underground coal gasification using the shaft structure. Background technique [0002] Underground coal gasification (Underground Coal Gasification, UCG) is the process of controlled combustion of underground coal to generate combustible gas through thermal and chemical effects on coal. This process is mainly realized in the gasification channel of the underground gasifier. [0003] The principle and process of underground coal gasification are exactly the same as the principle and process of coal gas production in surface gas plants, and the products are also the same, except that the former belongs to the chemical coal mining method, which is to ignite the buried deep coal underground and convert it into combustible gas. After CO, CH4 and H2, the gas is delivered directly to the surface. ...

AI Technical Summary

Problems solved by technology

However, there are various problems in the existing ignition methods.

In the prior art method, there are U-shaped wells for underground coal gasification, but there are problems such as long ignition time, high risk, unreliable ignition, incomplete combustion of coal, inability to ignite at a specific location, and limited combustion space.

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