Novel method for exploiting coal-bed gas

Abstract

The invention discloses a novel method for exploiting coal-bed gas. The method comprises the following steps: after breaking the coal bed by the known method using high pressure fluids, injecting high-temperature nitrogen gas (N2) with a temperature not less than 400 to 600 DEG C or high-temperature flue gas into a gas intake well; and standing for 7 to 15 days under sealed conditions to heat the coal bed with the high-temperature gas such that the small molecules of nitrogen gas can react with coal molecules to completely replace the coal-bed gas in the gaps and the molecular clusters of the coal bed. The coal bed is heated by the high-temperature gas to accelerate the penetration of the gas in the gaps of the coal bed and increase the desorption speed of the coal-bed gas, so that the yield of the coal-bed gas is increased.

Description

technical field [0001] The invention relates to a method for increasing the production of coalbed methane mining, in particular to utilizing high-temperature nitrogen (N 2 ) or a method for mining coalbed methane with fracturing fluid at a certain temperature, belonging to the technical field of coalbed methane mining methods. Background technique [0002] Coalbed methane is natural gas formed during coal formation and still stored in coal seams, the main component of which is methane (CH 4 ). It is a kind of unconventional natural gas, which is self-generated and stored in coal seams in the form of adsorption, including adsorbed gas on the matrix surface, free gas in coal seam cracks and cleats, dissolved gas in coal seam water, and free gas in interlayers between coal seams, etc. 4 parts. Coalbed methane is a high-quality energy and chemical raw material, and it is a good supplementary energy in the current energy shortage environment. [0003] my country's coalbed met...

AI Technical Summary

Problems solved by technology

[0004] The development of coalbed methane in my country is in the early stage of small-scale experiments, and a set of effective development engineering technology has not yet been formed. Every year, more than 1 billion cubic meters of coalbed methane (called gas in coal mines) are drained from coal mines, causing huge economic losses. , also has a certain impact on the environment, and there are several downhole accidents due to gas every year, causing casualties. , The desorption speed is slow, which makes the desorption and migration of coalbed methane very difficult. At present, most of the coalbed methane test wells in my country have low gas production and rapid production decline, and it is difficult to form a stable industrial gas flow. Therefore, it is necessary to focus on my country's coal reservoirs characteristics, how to find and study new production enhancement technologies for coalbed methane mining has become a difficult problem that people need to solve