Changes

[[File:Sandstone-Fig-12.png|thumb|300px|Figure 12: Plots of porosity versus total carbonates (a), and permeability versus total carbonates (b) for the sandstones in the study area. (After Luo Jinglan et al, 2002).]]

[[File:Sandstone-Fig-12.png|thumb|300px|Figure 12: Plots of porosity versus total carbonates (a), and permeability versus total carbonates (b) for the sandstones in the study area. (After Luo Jinglan et al, 2002).]]

 

====Effect of dissolution on reservoir quality====

====Effect of dissolution on reservoir quality====

The late diagenesis and epidiagenesis are the main phases for the formation of secondary dissolution pores, which result in the dissolution of detrital plagioclase and calcite cement, and thus enhancement of porosity. The acidic pore-fluids rich in organic and inorganic acids, as well as the meteoric waters, are the main dynamic force and fluid medium for the dissolution of fragments in the sandstones. Plagioclase dissolution was associated with the formation of kaolinite, which typically shows no evidence of dickitization or illitization.

The late diagenesis and epidiagenesis are the main phases for the formation of secondary dissolution pores, which result in the dissolution of detrital plagioclase and calcite cement, and thus enhancement of porosity. The acidic pore-fluids rich in organic and inorganic acids, as well as the meteoric waters, are the main dynamic force and fluid medium for the dissolution of fragments in the sandstones. Plagioclase dissolution was associated with the formation of kaolinite, which typically shows no evidence of dickitization or illitization.