Summary A compaction-based rock physics model and inversion method for the deep shale reservoirs is proposed. First, a shale rock physics model considering compaction is proposed using a CI-ODF. The elastic anisotropy of shale is affected by the preferred orientation of clay minerals, and the factors that cause the orientation of clay are complex. The existing theory only considers the effect of compaction on clay to describe the orientation arrangement of clay with the compaction ODF, which ignores the effect of non-plate particles on the preferred orientation of clay, and leads to the estimation error of petrophysical models. Therefore, a new theoretical CI-ODF model of clay orientation is proposed, which not only considers the influence of compaction but also further introduces the inhibition of other non-plate particles such as quartz, which makes the established shale anisotropic rock physics model more reasonable and the estimated elastic anisotropy more accurate. Secondly, based on the analysis of the compaction rock physics model, a compaction-based inversion method for the physical property parameters of deep shale reservoirs is proposed. This method can accurately achieve the inversion prediction of deep shale lithology and physical property parameters, which is validated by the measured data.

Compaction-Based Rock Physics Model and Seismic Inversion Method for Deep Shale Reservoirs