Analysis of ethanol as plug removal agent in near borehole zones for coal bed methane

Abstract

As coal bed methane (CBM) gas production can be reduced by reservoir pollution within near borehole zones, the feasibility of the use of ethanol as a plug removal agent and its impact on gas production are discussed in this paper. Four representative samples of Yima, Datong, Shaqu, and Yangquan coals were selected across a range of different ranks and were soaked with ethanol for experiments, and their change characteristics before and after treatment were compared using optical microscopy, mercury intrusion, and isothermal adsorption techniques. The results of this analysis revealed that the pore volume and porosity of coal samples increased following ethanol treatment, while the affinity for methane was significantly reduced. The use of ethanol was also advantageous because it reduced water lock and damage. This research showed that the use of ethanol as a plug removal agent in CBM near borehole zones has significant potential engineering applications.