Research on main geological controlling factors of coal reservoir indirect fracturing in Hancheng Block

In order to solve the adaptability problems of high-degree indirect fracturing technology in Hancheng Block, by adopting the method of control variables, geological factors influencing gas production of indirect fracturing was quantitatively analyzed, it was also proposed that in the same conditions improving the strengths of perforated roof could increase the optimizing effects of indirect fracturing. The results show that main geological controlling factors affecting the effects of indirect fra cturing by ordinal are sediment bedding, rhythm, shale intercalation, natural fracture and sand body aquosity; when roof is mudstone, brittleness index controls stimulati on effect of indirect fracturing, main geological controlling factors affecting the effects of indirect fracturing are roof of coal seam and structure of coal body.The effect of indirect fracturing is influenced when roof is sandstone, only if the brittleness index of mudstone is larger than 40, the indirect fracturing can play a role on increasing th e gas production. The impact of coal structure on indirect fracturing is mainly reflected as follows: if coal structure get fragmentized, it is more diffcult for artificial fractur e to extend in the coal seam, and it is prone to produce coal power during drainage, which has caused the effects of gas production caused by indirect fracturing.