Application of pre-stack simultaneous inversion to predict gas-bearing dolomite reservoir: a case study from Sichuan Basin, China

Abstract

Pre-stack simultaneous inversion is a seismic exploration technology which is widely applied to recognize lithology and detect oil and gas by analyzing the feature of amplitude variation versus offset (AVO). A gas-bearing reservoir can cause an obvious change in P-impedance and density. To effectively discriminate gas-bearing dolomite within Longwangmiao Fm. in Sichuan Basin of China, the pre-stack inversion method is employed by strict quality procedures. These procedures mainly include rock physics analysis, AVO modeling and pre-stack simultaneous inversion. Using the technology, P-impedance, S-impedance and density are obtained simultaneously. The distribution of gas-bearing dolomite is identified by P-impedance versus density cross-plotting from well data. The final prediction result indicates the existence of gas-bearing dolomite in the upper part of Longwangmiao Fm. in the study area, which is consistent with well data. Generally, pre-stack simultaneous inversion represents an effective method to predict gas-bearing dolomite reservoir and should be applicable in other study areas.