Accumulation and combination characteristics of coal measure gas of Shaoyang depression in the central Hunan

Based on the comprehensive experimental results incorporated with drilling data in Shaoyang depression,the coal-bearing strata were studied as a whole. The coal measure gas in lateral extension and vertical sequences and its accumulation and combination characteristics were investigated. Based on the study of representative wells in the study area,the favorable segment of unconventional gas and the gas types in the coal measure had been identified. It shows that shale plays a key role on coal measure reservoir in the study area,and Ceshui Formation primarily developed shale-related lithological association and shale gas-coalbed methane. It should be recognized that the distribution of Ce- shui Formation is unstable in Shaoyang depression,which leads to the different combination characteristics of coal measure gas in different areas. For example,coal plays a decisive role in the area of coal accumulation center.