Hydrogeological Conditions Of Controlling Gas In Coal Measures Of Wujiu Depression

Hydrogeological conditions control the accumulation of unconventional natural gas in coal measures,and are even more important for joint coal measures gas(CMG)development.Taking the Damuguaihe formation in the Wujiu depression,eastern Inner Mongolia,as the research subject,based on the sequence stratigraphic framework,the hydrogeological system of the depression was analyzed,and the cyclic superposition of the physical properties,fluid pressure state and the gas-bearing property of the coal measures aquifers and aquifuges was described.The hydrogeological contorls of CMG accumulation was analyzed,and then the CMG accumulation areas in the depression,such as the favourable,more favourable and destroyed ones,are divided in the views of hydrogeological control in vertical and horizontal dimensions.On this basis,the hydrogeological conditions of coal measures gas development was further analyzed,and it was predicted that the SQ3-SQ2 in Moguai-Shiwaru district is a sweet spot for the development of CMS in the depression.GMS was utilized to carry out three-dimensional hydrogeological modeling,and modflow model was established to simulate drilling and pumping.Finally,based on the coupling analysis of favorable hydrogeological conditions for the accumulation and exploition of coal-bearing gas,three types of coal system gas hydrogeological gas control was proposed,which were named that the upper gas and lower water block-trap type,the upper water and lower gas seal type and the integrated gas and water continuous type.The purpose is to provide reference for the exploration and deployment of CMG in the study area.