Rock physics analysis for shale gas formation “sweet spot” prediction in South China

Abstract

It is very essential to locate favorable area within shale gas formation and conduct further research on the “sweet spot” prediction and evaluation technique for the breakthrough of shale gas exploration and production in China. At present, the critical factors of shale gas “sweet spot” prediction are mainly TOC level and distribution as well as the shale formation brittleness evaluation, which normally have close relationship with rock physics analysis. In the study, we divide rock physics analysis into log curve correction and inversion, rock physics perturbation analysis and favorable elastic parameter crossplot. Through this workflow, we can find out relative sensitive elastic parameters to the variation of TOC and brittleness properties; map TOC and brittleness lateral distribution patterns within the shale gas formation with the seismic data inversion results; and finally achieve shale gas favorable area prediction by combining seismic and logging data along with synthetic gathers and AVA analysis. The research is significant in the way of providing important reference basis for shale gas formation “sweet spot” prediction and evaluation.