Study on fracturing and slicing decision method of multi layer overlay seam in East Yunnan and West Guizhou

In order to achieve the goal of successful hydraulic fracturing of coal seams to obtain industrial production capacity, a fracturing slicing decision method according to the multi layer overlay seams was provided and the method was based on the seam pressure gradient and the permeability as the rigid judgement index. With the simulation results of the seam crack expansion as the basis, the target function was established and the best perforation combination was optimized. A judgem ent was conducted on the applicable conditions of the packing mode and the suitable fracturing method was judged. The method could effectively solve the compatibilit y between the gas bearing system of the seam and the internal share of the system. With a mine in a block in Southwest China as a case, the fracturing slicing decision was conducted. The divided results showed that there were two gas bearing systems existed and four small seam groups with large difference of the permeability. An op timization of the perforation location was conducted on Ab seam group. A combined seam fracturing was proposed and conducted on No.4 and No. 5 seams. The packe rs were applied to seal the top seam and low seam. The application of the method showed the suitability to the multi layer overlay seams.