Method for extracting coalbed methane and coal together

Abstract

The invention relates to a method for extracting coalbed methane and coal together. The method includes a well drilling step, a pressing crack cut-through step, a coalbed methane extracting step an ignition step and an underground gasification step. According to the method, an underground coal gasification technology and a coalbed methane extracting technology are combined, a coal bed can be heated by high temperature of underground gasification to improve breathability of the coal bed and increase extracting ratio of the coalbed methane, well drilling and pressing crack cut-through processes can be performed by the aid of the coalbed methane, and the underground gasification coal extraction efficiency is increased.

Description

technical field [0001] The invention relates to a mining technology of a novel underground carbon-containing organic mineral reservoir, in particular to a method for co-mining underground coal bed gas and coal. Background technique [0002] Coal is the main energy source in my country, accounting for about 70% of the primary energy composition, and the total amount of resources is relatively abundant. The total amount of resources is predicted to be about 4.5 trillion tons (shallow than 2000 meters), of which the resources with a depth of 600 meters or less The coal reserves only account for about 25%. Based on the current coal mining depth (400 meters), at least 80% of the total underground coal resources in my country have not been developed and utilized. The development of deep coal resources will be A long-term job. With the increase of mining depth, the content of coal-associated resources - gas (also known as coalbed methane) also increases rapidly. According to the eva...

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Problems solved by technology

[0005] Underground coal gasification technology is currently the most effective technology for mining deep coal resources, but the existing underground coal gasification technology usually only considers the gasification of coal seams, and with the increase of coal mining depth, the content of coal seam gas will increase rapidly, so It is inevitable to encounter problems with the extraction of coalbed methane, and the specific problems include: (1) For coalbeds rich in coalbed methane, if the gasification of coalbeds is directly implemented, there will be problems such as threats to safety and waste of resources ; (2) If the conventional coalbed methane mining method is adopted without considering the combination with underground gasification technology, then the subsequent implementation of underground coal gasification will have overlapping functions such as drilling and increase investment costs; ( 3) Inject CO into the coal seam 2 Can increase coal seam CH 4 However, the production of CBM can be increased only in the early stage of CBM extraction, but the cracks are easy to close in the later stage, and the production of CBM will drop rapidly; (4) As one of the intermediates and products in the gasification process, CO 2 Participating in a series of oxidation-reduction reactions, it is an important component in the export gas, and its content accounts for about 15-60%. It is one of the important factors related to the calorific value of the gas and the content of effective components, but the existing processes usually do not consider CO 2 recycling and utilization

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