Delineation and quantification of effective source rocks using 3D geological modeling in a lacustrine basin

Abstract

The identification and quantification of effective source rocks are critical for hydrocarbon exploration, but traditional methods have limitations in lacustrine basins due to their complexity and heterogeneity. For example, geochemical analysis is constrained by the number and distribution of samples, well logging methods can only reflect local information, and seismic inversion methods are limited by the quality and resolution of data. We propose a geological modeling approach that combines geophysical techniques and geological and geochemical data to delineate effective source rocks and quantify hydrocarbon resource potential. The workflow includes mudstone classification, geochemical data analysis, building predictive models, constructing 3D geological models, filtering effective source rocks, and basin simulation. Taking the Fushan Depression, South China Sea, as an example, we estimate the total volume of effective oil source rocks at 323.48 km3 and effective gas source rocks at 67.43 km3, and identify favorable areas for conventional and unconventional hydrocarbon exploration. The results demonstrate that our proposed approach enables precise delineation of the spatial distribution of effective hydrocarbon source rocks and quantification of their potential for hydrocarbon generation and expulsion. Our study constitutes a reference case for assessing effective source rocks in other lacustrine basins due to the successful integration of multiple available of data and its practical applications.