Prediction and distribution characteristics of deep coal seam fracture pressure in Hexi Block of Daning-Jixian
The accurate prediction and distribution characteristics of deep coal seam fracture pressure are directly related to the evaluation of borehole stability and reservoir fracability.In order to further establish a calculation model for deep coal seam fracture pressure and clarify the spatial distribution characteristics of fracture pressure,the deep 8# coal seam of Hexi Block in Daning-Jixian was taken as the research object.On the basis of fully excavating geophysical logging information,the theoretical model of the fracture pressure of deep coal seam is given by introducing factors such as tensile strength,coal structure index and fracture development degree.The logging methods of vertical stress,pore pressure,tensile strength,effective stress coefficient,Poisson's ratio,Young's modulus and other parameters are defined,and then a calculation model of fracture pressure suitable for deep coal seam is formed.By programming the method,the computer visualization and automatic processing of the fracture pressure of the deep 8# coal seam in the block are realized,and the three-dimentional spatial geological model of the fracture pressure of the 8# coal seam is established.The results show that the deep coal seam fracture pressure calculation model based on logging data can accurately predict the deep coal seam in the block,and the maximum relative error is 13.2％.The low value area of fracture pressure is mainly distributed in the middle-northeast and south-southwest well areas.This method can provide a new way for geophysical logging to predict the fracture pressure of deep coal seam,and provide technical support for wellbore stability evaluation and reservoir fracability evaluation.
NETL
NSTL
万方数据
