Abstract Tight sandy conglomerate reservoirs have become increasingly significant in recent decades. However, complex depositional environments and intense diagenesis typically result in clay-rich sandy conglomerates that exhibit strong anisotropy, low porosity, and low permeability, gas-water relationships. As a result, developing a practical rock physics model for seismic interpretation remains challenging. Here, we introduce an adaptive anisotropic rock physics modeling workflow based on clay classification for sandy conglomerate formations in the Mahu Sag. Unlike traditional sandstone rock physics models, this workflow emphasizes how clay (such as distribution and fraction) influences elastic velocities. By incorporating different clay types, such as frame clay and pore-filling clay, the model more accurately reflects key mineral and fluid features that affect P- and S-wave velocities. More importantly, this method automatically selects either an anisotropic Differential Effective Model (Aniso-DEM) or an isotropic DEM model depending on local clay content, enabling lithology- and zone-specific rock physics modeling. Field data tests from 5 wells in the Upper Wuerhe Formation in Junggar Basin, China, with certain sections exhibiting higher clay content (40%), indicate that this workflow achieves an average prediction accuracy of 95% for P-wave velocity across the entire conglomerate interval. For S-wave velocity, the 90% prediction accuracy is based on data from a single well.
Zhang et al. (Sun,) studied this question.