Calcite cement, formed in the early diagenetic stage, makes the great contribution to improvement of the reservoir quality, when it was dissolved and forming secondary porosity in acidic fluid later.

• 早期胶结作用阶段结晶沉淀的方解石胶结物,在后期酸性流体的作用下发生溶解作用产生的次生孔隙对储层物性的贡献极大。