Microscopic Distribution and Development Strategy of Residual Oil in Tight Sandstone

Pore and permeability are distributed discontinuously unevenly in the dominant sedimentary model of lateral accretion body inside meandering river point bar Fuyang reservoir Yushulin oilfield. Based on water flooding experiments field core samples, influence pore conditions residual oil distribution type cutting rate was studied by using microscopic visualization technology enabled through a photolithographically fabricated glass model. It is found that samples shows five discontinuous types, which cluster, columnar, droplet, membrane, blind end. In stages with low, medium, high rates, proportion clustered different high, reflecting situation it difficult for injected to spread widely tight reservoirs. With decrease permeability, membrane end gradually increases, indicates thin throat can produce large restrictions oil, resulting enrichment. At same time, experiment carried out changing displacement direction periodic injection. beneficial recovery avoided seepage big throat, increased more than 2.14%. Periodic injection, conducive adjusting pressure difference, reduced constraining force 3.98%. The actual well area closed coring wells dynamic production data preferred application experimental research results. Changing injection 3%.