Carbonate Rock Physical Property Parameter Substitution Method Based on Rock Physics Models

The physical properties of carbonate rocks play a crucial role in the exploration and development of oil and gas. Carbonate rocks are characterized by multiple types of porosity, and the complex porosity types result in a highly discrete relationship between porosity and elastic parameters. In this paper, a method based on rock physics models for substituting the physical property parameters of carbonate rocks is proposed. Initially, rock physics modeling is conducted on carbonate rock reservoirs, and inversion of the equivalent pore aspect ratio in the model is performed. During the substitution, all other parameters are kept constant, and only one of the porosity, calcite content, water saturation, or volumetric fraction of pore shapes is changed. In combination with amplitude versus offset (AVO) theory, forward modeling simulations are performed. The simulations reveal that the impacts of changes in porosity and pore shapes on seismic response are more significant, far exceeding the influences of variations in calcite content and water saturation, which have a weaker effect on seismic response. Application of actual data demonstrates that the method for substituting the physical property parameters of carbonate rocks proposed in this article can effectively analyze the impact of changes in physical property parameters and pore shapes, characterize the physical properties of rocks, and determine the types of rock porosity.