Coalbed Methane in China: Geology and Exploration Prospects

Abstract

China has given priority to coalbed methane (CBM) in developing new energy resources for recent years in its effort trying to alleviate energy shortage and air pollution. As an unconventional natural gas, CBM adsorbed on the internal surfaces of micropores and fractures in coal seams is quite different from conventional oil and gas in exploration and development. This paper discusses the CBM geology and assessment and predicts its exploration prospects in China Three factors of evaluating CBM potential are proposed, coal abundance, gas resource, and producibility, which are controlled by coal depositional environments and later tectonic evolution. China is endowed with vast coal resource, which provides substantial base for methane generation and storage. The CBM abundance in China is largely controlled by regional coal metamorphism because metamorphism directly determines caol gas-generating and -adsorbing capacities. Burial depth is the secondary factor controlling CBM abundance. CBM producibility primarily depends on cleat permeability of coal seams and is a crucial variable in evaluation of CBM potential. North China Bureau of Petroleum Geology has made a signifcant breakthrough in CBM exploration at the Liulin CBM pilot site, the Shanxi province, China, which demonstrated that the areas with optimistic integration of the above three evaluation factors exist in China. Those areas are geologically comparable to Black Warrior Basin and San Juan Basin in USA, where commercial CBM developments have been successful. The paper reviews the CBM exploration and development activities in China and concludes that CBM industry will fundamentally take shape in China with the advent of the 21st century.