Analysis of Factors Affecting Productivity of Chang 4+5 Ultra-Low Permeability Reservoirs in Jiyuan Area

Productivity prediction is a technology for comprehensive evaluation of reservoir's oil-producing capacity, having important significance for early evaluation of oilfield and formulation of oilfield development plan. The percolation mechanism for ultra low permeability reservoirs is extremely complex, making productivity prediction difficult. The factors affecting oil productivity including reservoir parameters, production pressure difference and fluid property have been analyzed according to Chang 4+5 reservoir and production test data in Jiyuan area. Reservoir parameters have complex impact on oil productivity in production test: thickness of oil-bearing interval, electric resistivity, porosity, permeability and other factors all affect productivity in production test. The productivity in production test increases along with increase of production pressure difference under various thicknesses. The productivity is reduced with increase of crude oil viscosity. Reservoir parameter combination through comprehensive analysis is well related to productivity in production test, enabling the building of a regional productivity prediction model.