Method Of Forecasting Exploitation Characteristics Of Solution-Gas-Drive Reservoirs Based On Material Balance

As an important way to enhance the oil recovery,solution-gas-drive has been widely used in oil field development.Therefore,it is of great significance to study solution-gas-drive reservoirs against guiding the rational development of oil field.The paper has taken the oil-gas two phase flowing during the process of solution-gas-drive reservoirs as research target.Based on the principle of material balance,equation of motion and continuous equation,the paper has established the model of one dimensional One-dimensional unidirectional closed reservoir,vertical well of circular closed reservoir and vertically fractured well of circular closed reservoir respectively.The conclusions are listed as follows:1?Research of the pvt characters of oil and gas has been conducted.The dissolved gas and oil ratio,the volume factor of oil and gas as well as the viscosity of oil and gas have been calculated by empirical formulas of different scholars.2?The oil-gas two phase flow material balance equation and differential material equation have been established based on the principal of solution-gas-drive reservoir.The paper can get the relationship of oil saturation and average reservoir pressure by the methods of Euler and Runge-Kutta.3?An flow equation of one-dimensional unidirectional closed reservoir has been established.The dimensionless linear equation can be gotten by introducing the quasi-function and dimensionless definition.The paper can also derive the productivity equation by Laplace transformation,Duhamel convolution and Stehfest numerical inversion.4?The paper has established the oil-gas two phase flow equation of vertical well in circular closed reservoir.The pseudo-steady state productivity equation could also be derived.It has a great agreement between the two result by comparing the numerical solution of model that established by Eclipse and the semi-solution.Effects of the absolute permeability of reservoirs k,original pressure of reservoirs p_i and bottom hole pressure p_wff to the production dynamics of reservoirs have been analyzed successively.5?The oil-gas two phase flow equation of vertically fractured well in circular closed reservoir has been established.Then we got the semi-solution by combining the pseudo-steady state productivity formula and the equation of material balance.It has a great agreement between the two result by comparing the numerical solution of model that established by Eclipse and the semi-solution.Effects of dimensionless conductivity of fractures C_fD and skin factor S_f to the productivity of oil and gas wells can be gained respectively.