Thermal injection stimulation technology

which is suitable for coal seams with low water content and difficult pressure reduction and desorption

is an effective method to increase coalbed methane production besides hydraulic fracturing. Based on the literature research at home and abroad

the stimulation mechanism of coalbed methane heat injection is expounded

the influences of heat injection and temperature rise on adsorption and desorption and permeability of coal seam are analyzed

and the thermal-hydraulic-mechanical coupling relationship in the process of thermal coalbed methane production are summarized. Then

four methods

which are thermal steam injection

thermal CO

2

inj

ection

microwave thermal injection and coal seam burning

are introduced

and their technical principles

characteristics and research progress at home and abroad are summarized. The study shows that the method of heat injection can promote the desorption of coalbed methane

increase the content of free coalbed methane and achieve the purpose of increasing the coalbed methane production. Meanwhile

thermal cracking and coal pyrolysis caused by heat injection can improve the pore structure of coal seam

and communicate and increase the fracture network of coal seam

which are beneficial to the diffusion and seepage of coalbed methane. The thermal injection stimulation technology of coalbed methane can effectively solve the problems of low water content

difficult depressurization and desorption

and strong water sensitivity of coalbed methane

which is another potential stimulation method to replace hydraulic fracturing.