THE EFFECT OF BIOTURBATE STRUCTURE ON THE PETROPHYSICAL PROPERTIES OF SANDSTONE RESERVOIR
Ji Youliang Zhao Chenglin Liu Menghui (Dept. of Petroleum Exploration)
Bioturbate structure can alter the petrophysical properties of sandstone reservoir. Bioturbate structures are abundant in the lower member of Dongying formation in Liaodong Bay Basin. The amount of clay and organic material of the reservoir was decreased by the activity of organisms ana the pstropbysicsl properties of the reservoir could be improved. With the enhancement of bioturbate structure, the porosity, permeability and oil saturation of the reservoir became higher. Before the migration of hydrocarbon, early calcite cementation developed in the reservoir of Es4 member of Dongpu depression, which was favored by the high original porosity and permeability. The calcite cement could worsen the petrophysical properties of this biotur-bated parts of the reservoir while clay retarded cementation in the non-biotur-bated parts and thas the porosity and permeability remained relatively high.