关键词: 水驱油藏, 剩余油饱和度, 数值模拟, 预测模型, 孔隙体积, (φ)函数法

Abstract: Based on the Buckley-Leverett equation (φ-Function),the relationship between residual oil saturation and the pore volume of cumulative fluid flow rate in one-dimensional homogeneous formation model was established.This relationship was applied to three-dimensional heterogeneous reservoirs.A simple and practical modeling method for predicting the distribution of residual oil in a reservoir after long-term water drive was developed.Compared with the traditional reservoir simulation technique,the new method does not need to solve the discrete nonlinear equations fully coupled or simultaneously,while solving pressure and saturation fields.The new method needs a sequential algorithm in the solution.In addition,the new method has no limit for ratio of time step size to fineness(or coarseness) in spatial discretization,which avoids computational intensity in solving large and sparse matrix systems of discrete mass-balance equations for multiphase flow.Furthermore,there is no non-convergence and instability during numerical computation,which significantly improves the efficiency of numerical modeling.The new method can be used to incorporate various types of production and measured data from reservoirs and perform automatic history matching.This scheme makes it possible to predict residual oil distribution using personal computer with incorporation of large and actual field data sets.

Key words: water drive reservoir, residual oil saturation, numerical simulation, prediction model, pore volume, φ-function method