The river channel sandbodies in Zhaoshiyao area are characterized by low compositional maturation and low textural maturation

high debris and feldspar contents.The filling materials of the sandbodies are mainly argillaceous

siliceous

iron substance and carbonatite.The sandbodies underwent three diagenetic periods such as syngenetic

burial and epidiagenetic periods.Their porosity and permeability are closely related to their granularity.The porosity of the sandbodies could be classfied into 8 pore types and 4 kind of pore textures.The pore textures are related to the granularity and the filling materials.It has been proved by study that the mid and lower parts of the meandering river point bars usually have the best porosity and permeability

the bottom part is secondary and the top and marginal parts ane the worst.