Complicated controllable displacement of equivalent filtrational resistance with several slugs

The constraint of complex geological conditions and the high heterogeneity of oil reservoirs make filtration resistance vary greatly in the process of water flooding. Fluid tends to flow along high permeability formation with low resistance, leading to a smaller reservoir swept volume and a lower producing degree. In order to control the resistances of all channels in the seepage field to balance the resistances as much as possible, a new method of controllable displacement of equivalent filtration resistance with several slugs was presented. A series of mathematical models were established for describing complicated controllable displacement on the basis of the mass transport fluid mechanics, the material balance principle and the characteristics of each slug. After simplification the one-dimension analytical solution was derived through integral transformation. Combined experimental results with the theoretical analysis of pressure distribution calculated by the filtration theory, it is demonstrated that the controllable displacement of equivalent filtration resistance with several slugs can greatly enlarge the swept volume, reduce the water cut, activate oil in the low permeability reservoir and enhance the oil recovery.