Method and device for displacement of coal seam gas with supercritical carbon dioxide

Abstract

The invention belongs to the technical field of coal seam gas exploitation and discloses a method and a device for displacement of coal seam gas with supercritical carbon dioxide. The device comprises a coal seam gas displacement device body which comprises an upper capsule group and a lower capsule group. The upper capsule group is internally provided with a grouting area I, the lower capsule group is internally provided with a grouting area II, and a supercritical carbon dioxide radiation area is formed between the upper capsule group and the lower capsule group. The method and the device have advantages that supercritical carbon dioxide energy loss can be avoided, and states of the supercritical carbon dioxide injected into coal seams finally are guaranteed; structural simplicity, convenience in use, easiness in construction, low cost, safety, high efficiency and applicability to large-scale industrial application of the supercritical carbon dioxide to coal seam gas exploitation are realized, coal seam permeability is improved, and coal seam gas exploitation rate is increased.

Description

technical field [0001] The invention relates to the technical field of coal bed gas exploitation, in particular to a device and method for displacing coal bed gas with supercritical carbon dioxide. Background technique [0002] Coalbed methane, commonly known as "gas", is mainly composed of methane, which is an associated gas in the process of coal formation and metamorphism, and its reserves are very abundant in my country. The calorific value of coal seam gas is equivalent to that of conventional natural gas, 2 to 5 times that of general-purpose gas, and rarely produces pollutants after combustion, which is a high-quality clean gas energy. However, because most of the coal seams in our country are low-permeability coal seams, the gas extraction rate is low. [0003] At present, the commonly used gas drainage methods are: intensive drilling gas drainage, hydraulic fracturing drainage, hydraulic punching drainage, enhanced drainage of mining liberated layers, hydraulic slot...

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Problems solved by technology

[0005] Although after various tests, we know the effect of supercritical carbon dioxide on coal, there are still many problems in the technology of preparing supercritical carbon dioxide and injecting it into the coal seam. Energy will be lost, so that the final supercritical carbon dioxide injected into the coal seam cannot meet the conditions. So far, there is still no device for the large-scale industrial application of supercritical carbon dioxide to coal seam gas mining. Therefore, how to avoid supercritical carbon dioxide energy loss , to ensure the supercritical carbon dioxide state that is finally injected into the coal seam, and to make the safe and efficient application of supercritical carbon dioxide in large-scale industrialization in coal seam gas mining is an important research topic in the field of coal bed methane mining technology

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