UNDERGROUND COAL GASIFICATION PROCESS COUPLED WITH ON-SITE CARBON STORAGE AND ENHANCED HYDROCARBON RECOVERY IN NORTH DAKOTA WILLISTON BASIN

Underground coal gasification (UCG) is a promising clean coal technology which directly converts coal into syngas in the coal bed. Compared with the conventional mining process, the UCG can utilize coal reserves that are too deep to be mined economically, and convert the coal reserves into high rank energy with a higher rate, lower cost and smaller land occupation. The produced syngas from UCG can be used as town gas, feed material for other chemical products, or generate electricity in a on-site combined cycle (CC) power generation system, Similar to the integrated gasification combined cycle (IGCC).When the produced syngas is used in the on-site combined cycle, free CO₂ emission is realized by incorporating with the carbon capture and storage (CCS) process. The CO₂ can be captured by a pre-combustion capture system. The captured CO₂ is then injected into the adjacent coal beds which are unsuitable for the UCG utilization, similar to enhanced coal bed methane recovery (ECBM) process. Besides, the cavities created by UCG process and existing boreholes and hydraulic fractures may also provide extra potential CO₂ storage capacity in addition to those of the conventional storage methods. Therefore, the UCG-CC-CCS may offer a cost effective and clean way to exploit the potential of the abundant global coal reserves. This study will aim at developing a roadmap on the feasibility study of the UCG and CO₂ storage potential in North Dakota Williston Basin.