A Microwave Heating Technology for Coalbed Methane Recovery

As a heat injection technology, microwave heating technology can be applied in the coalbed me-thane (CBM) development and to enhance the recovery. In order to raise the temperature of coal reservoir and improve its permeability, a microwave heating technology for coalbed methane is proposed and two structure schemes of waveguide antennas for heating are designed in this paper. Through the comparisons of CT scanning and SEM results before and after microwave treatment by an experimental microwave oven, the internal microstructure variation of coal samples which are from the Hancheng area and the mechanism of cracks generation during microwave heating process are studied. Taking the microwave-heating model of CBM reservoir with a coaxial antennas for example, the electromagnetic field distribution in the coal reservoir and the temperature change law during the heating process are simulated by use of COMSOL software, and the effects of different conditions (such as power, frequency and hole distribution of antenna) on the reservoir temperature are analyzed. Based on the design, the experiment platform of microwave heating for coal reservoir is set up. The experimental results prove that the design of microwave heating technology for CBM recovery is feasible.