Rock Physical Properties and Modelling of Carbonates

Abstract

Summary Leikoupo Formation carbonate of Sichuan Basin is the important gas reservoirs for exploration in china. The elastic properties of carbonate rocks vary significantly between reservoirs. The rock properties and corresponding seismic rock-physics properties are not completely known for Leikoupo Formation carbonate. Based on the observation of rock microstructure (scanning electron microscope, etc.) and petrophysical experiment, this study analyzed the characteristic of elastic property, and established the corresponding petrophysical model according to the microstructural characteristics for carbonate. There is a significant correlation between porosity and dolomite content in the carbonate reservoir of Leikoupo Formation. Dolomitization and dissolution are the main factors controlling the evolution of rock pore system. During diagenesis, dolomitization displaces calcite, while dissolution transforms the pore system of reservoir rock. Therefore, when the dolomite content is less than 60%, calcite is the rock skeleton matrix, the reservoir rock porosity is low (< 2%); when the dolomite content is more than 60%, dolomite and calcite are used together as the skeleton matrix of the rock. The porosity of reservoir rock increases rapidly under the action of dissolution (5%~20%). Based on the DEM and voight-hill average model can be used to establish the rock physical model of this area more accurately.