Sleeve for coal underground gasification, and intake and exhaust hole structure for coal underground gasification

Abstract

The invention discloses a sleeve for coal underground gasification, and an intake and exhaust hole structure for coal underground gasification, which relate to the technical field of coal underground gasification, and aim at preventing a stratum with a gasification agent from invalid loss, and promoting the running of the sleeve. The sleeve for coal underground gasification comprises an upper sleeve and a lower sleeve, wherein the upper end of the lower sleeve is arranged in the upper sleeve in a matching and penetrating manner, and the lower sleeve is capable of freely sliding along the inner wall of the upper sleeve; the upper end of the lower sleeve and the lower end of the upper sleeve are funnel-shaped structures, and the lower-end funnel-shaped structure of the upper sleeve is capable of limiting the upper-end funnel-shaped structure of the lower sleeve, thus preventing the upper end of the lower sleeve from separating off from the lower end of the upper sleeve. The sleeve for coal underground gasification disclosed by the invention is used for the intake and exhaust hole structure for coal underground gasification.

Description

technical field [0001] The invention relates to the technical field of underground coal gasification, in particular to a casing for underground coal gasification and a gas inlet and outlet structure for underground coal gasification. Background technique [0002] With the development of underground coal gasification technology, organic matter gasification units are more and more widely used in the field of underground coal gasification technology. The smallest solid organic matter gasification unit is composed of inlet holes, outlet holes and gasification channels. The holes transport the gasification agent to the organic matter, and react with the high-temperature organic matter for oxidation, reduction, and pyrolysis. Due to the reaction between the agent and the organic matter, the cavity formed at the end of the air inlet hole will become larger and larger, and the temperature of the air outlet hole will become higher and higher. When the borehole falls at the bottom or ...

AI Technical Summary

Problems solved by technology

[0005] First, when the connection between the upper and lower casings adopts a common structure, because the lower casing and the formation are not fixed, there may be surrounding rock formations that are not completely squeezed with the lower casing before drilling. Especially during high-pressure fracturing, it is easy to leak gas from the connecting part of the upper and lower casings into the formation around the casing, which will increase the loss of gasification agent during the penetration process

[0006] Second, when the drill hole is an outlet drill hole, the outlet gas will discharge the drill hole together with fine ash and gaseous and liquid water. As the gas outlet time increases, these fine ash and water will be mixed and deposited on the connection. At the boss of the part, under the action of high temperature of the gas outlet, these deposits will become very hard, thus preventing the upward expansion of the lower casing and affecting the operation of the casing

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