Heterogeneity of Chang 2 reservoir in Zhangjiawan area,Zhiluo oilfield

In order to develop the oil and gas reservoirs rationally and improve the recovery ratio,the paper has studied the characteristics and heterogeneity in Chang 2 reservoir by the experimental testing techniques like core observation;rock slices identification,scanning electron microscopy,pressure mercury test and so on.The results show the rock type of Chang 2 reservoir are mainly fine-grained feldspathic sandstones.Detrital components are quartz,feldspar,rock debris and small amounts of biotites.The maturation of the mineral composition and structure are both low.The average porosity in Chang 2 reservoir is 13.8% and the average permeability is 3.04×10-3 μm2,which belongs to mediumlow porosity and ultra-low permeability.The pore types are mainly residual intergranular pores,intracranial and intergranular dissolved pores.The pore structure is intermedia pore and fine throat.The interlayer heterogeneity is weak,while the inner layer and areal heterogeneity are relatively strong in the reservoir.Finding out the Chang 2 reservoir characteristics not only can better guide the Zhiluo Oilfield reasonable development,but also provide a reference to the similar ultra-low permeability reservoirs development in Erdos Basin.