In dealing with reservoir rocks, it is necessary, because the cementing materials may seal off a part of the pore volume , to define total porosity and effective porosity.

• 在研究储层岩石时，因为胶结物会堵住一部分孔隙的体积，所以对于油藏流体有必要定义总孔隙度和有效孔隙度。