Simulation experiment for the dissolution of carbonate rocks of the Yingshan formation on the northern slope of Tazhong uplift

Dissolution experiment and microscopic observation are carried out to research micro-corrosion mechanism of carbonate rocks. The corrosion process and micro features of three types of carbonate rocks in the Yingshan formation on the northern slope of Tazhong uplift are studied in this paper. The results show that the dissolution quantities of three kinds of carbonate rocks, parry bioclastic limestone, dolomitic limestone and mud-crystal grain limestone, are almost the same. Because of the selective dissolution for composition and microstructure of rocks, micro-corrosion characteristics of these three kinds of carbonate rocks are significantly different. The surface of sparry bioclastic limestone and mud-crystal grain limestone are overall reduced by corrosion. The calcites of dolomitic limestone are eroded and lowered to formmould pores. The dolomites of dolomitic limestone are eroded into honeycomb-like pores that protruding on the rock surface. The inter-crystal fractures of dolomite are enlarged by dissolution and become interconnected. That is of important significance for reservoir and permeability of oil, gas and groundwater.