Shale brittleness prediction by geophysical methods

Taking the Jurassic continental shale gas of the JN area on the Eastern Sichuan Basin as an example, this paper discusses difficulties and problems in predicting shale brittleness, and puts forward some geophysical prediction approaches. Based on shale rock physics modeling and analysis of shale brittleness characteristics, a pre-stack elastic parameter inversion is applied to calculate the shale brittleness. Based on approximate Zoeppritz equation and Bayesian parameter estimation theory, this method uses the covariance matrix to describe parameter correlation degree. And then the inversion results are constraints by rock physical relationship between parameters, and get shale information about longitudinal wave, shear wave and density, and finally obtain quantitative description of shale brittleness. The brittleness index of seismic prediction has better consistency with brittleness mineral content by examining.