Difference of CBM development conditions in Shouyang and Shizhuang blocks, Qinshui basin

Based on the geological data and drainage dynamic data in two blocks, this paper analyzes the causes of difference between the two blocks from three aspects including resources, fluid mobility and fracturing engineering conditions, discusses the key issues of CBM development of Shouyang block and gives some suggestions. The study shows that the resources and the fluid mobility of each coal seam in Shizhuang are wonderful, so Shizhuang block is suitable for CBM development. The resources of each coal seam in Shouyang block are weak but the ultimate recovery resources of multiple coal seams is up to 1.57×10⁸ m³/km² and the desorption potential is also satisfactory since desorption quantity index of each single seam is about 9 m³/t. What's more, the fluid mobility is beneficial to CBM development, the average value of permeability is 7.57×10^-3 μm², even though the adsorption time is more than 15 d. Compared with Shizhuang block, there are not only more sandstone aquifers with high permeability in coal measure strata in Shouyang block, but also the actual implementation of fracturing is bigger, so the fault and hydraulic fractures are easy to connect coal seam with aquifers. It is suggested that multiple coal seams developed together is a necessary way for Shouyang block. When it comes to select appropriate well horizon, it is crucial to avoid faults, take into account the lithological combination of coal roof and floor and optimize or control fracturing volume.