Research on Porosity of Chang 2 Reservoir in Zichang Oil Field

Many of reservoirs in Ordos basin are in low porosity and permeability,which are characterized by small pore with complex texture. As complexity of pore texture has great influence on displacement efficiency,the paper makes an evaluation on the porosity of studied reservoirs by analyzing the geology condition,four- property relationship and interpretation model of porosity. The result shows that the proportion of oil- bearing core is 98. 5% when the porosity higher than 10%,and on the contrary,there are few oil- bearing cores when the porosity lower than 10%. The conclusion is the lower limit of porosity in this region is 10%.