High rank coal structure and log interpretation method of fracture pressure in Shouyang block

Coal structure and fracture pressure directly affect the engineering design and gas production effect of coalbed methane development. There are many evaluation methods of coal body structure, for the high rank coal in Shouyang block, the geological intensity factor(GSI) method has the best effect, but it has strong regional applicability; The heterogeneity of coal seam is very strong, and the prediction effect of fracture pressure is not ideal. In view of the above problems, the geological intensity factor method is optimized by introducing parameters such as coring rate and continuous coring length, and then a quantitative evaluation method for coal structure in this area is established. The results show that the accuracy of logging interpretation is 86.3%. At the same time, based on the evaluation of coal structure, the coal fragmentation index is introduced and the prediction formula of coal seam fracture pressure is established. The relative error between the calculated fracture pressure and the actual value is 2.5%-16.1%, and the average error is 8%. The prediction method of coal structure and fracture pressure is suitable for high rank coal in Qinshui basin, and it can provide strong support for CBM exploration, development and fracturing.