Joint Stochastic Inversion of Elastic-electrical Data for Reservoir Parameters of Gas Hydrate Bearing Sediment

Abstract

Summary Reservoir parameters of gas hydrate bearing sediments are significant to reservoir characterization. Typically, these parameters are evaluated separately based on single well log measurements with simple linear or empirical rock physics models. This paper proposes a scheme for joint stochastic inversion of elastic and electrical data to predict reservoir parameters with non-linear rock physics models. This scheme first establishes the elastic-electrical rock physics templates to generate a certain range of hydrate saturation, porosity and clay content, and then considers these ranges as the prior information for a subsequent inversion. Furthermore, a stochastic inversion method is used to achieve different realizations, where mean values are treated as the interpretable reservoir parameters and the different realizations quantify the inversion uncertainty. Finally, we implement this joint inversion approach to the well logs measured at site 1250F, Hydrate Ridge. Results show that hydrate saturation, porosity and clay content have a good agreement with core samples. Meanwhile, the quantitative analysis of these realizations show that the maximum standard deviation is no more than 8%. Based on these results, we conclude that our joint inversion scheme is feasible and reliable when integrating elastic and electrical data for reservoir parameter estimation.