Abstract:
The Maokou Formationcarbonate reservoirs in the central Sichuan Basinexhibit well-developed dissolutionpores, vugs, and fractures, pronounced heterogeneity, and diverse types. This study aims to identify their types and establish the log-based identification criteria for various reservoir types. First, this study classified the reservoir types based on the analysis of casting thin sections, core photos, and micro-resistivity imaging logs.Moreover, it determined the conventional log response characteristics of different reservoir types. Finally, it conducted log-based identification of reservoir types using the fracture porosity (
φf) -secondary porosity index (
RP) cross-plotting method. The results are as follows: (1)The Maokou Formation carbonate reservoirs in the central Sichuan Basin can beclassified into four types, i.e., fractured-vuggy, fractured-porous, porous-vuggy, and matrix porous reservoirs; (2) Fracture porosities calculated from different models are more similar in the case of more developed fractures, and dissolution pores and vugscan affect the fracture porositycalculation results to some extent; (3) The
φf-
RP cross-plotting method can effectively identify reservoir types. These research results provide technical support for the log-based identification of carbonate reservoir types.