The paper presents the results of simulation and study of mixture - oil, gas and water - flows in porous medium using three-phase, three dimensional "Black oil" model. For discretizing the system of mathematical equations, the finite volume difference method was used. To solve numerically the system of discretized equations the IMPES and iterative methods were chosen. | Vietnam Journal of Mechanics, NCST of Vietnam Vol. 24, 200?, No3 (151 - 166) NUMERICAL MODEL OF THREE PHASE-THREE DIMENSIONAL FLOW IN POROUS MEDIA FOR RESERVOIR SIMULATION DUONG NGOC H AI AND D ANG THE B A Institute of Mechanics, N CS T, 264 Doican, Hanoi, Vietnam ABSTRACT. The paper presents the results of simulation and study of mixture - oil, gas and water - flows in porous medium using three-phase, three dimensional "Black oil" model. For discretizing the system of mathematical equations, the finite volume difference met hod was used . To solve numerically the system of discretized equations the IMPES and iterative methods were chosen. The numerical results are compared wit h a number of analytical solution, experimental measurement and calculation results of t he other authors and they shown a good agreement. The model can be developed, adapted and used for study and simulation of mixture - oil, gas and water - flow in different experimental and real field conditions. 1. Introduction The simulation is a good way to investigate many processes and phenomena in the nature and industry. In the petroleum indust ry t his method is applied intensively also (see, for example, Duong Ngoc Hai et al. 1988, 1989, 1992; Nigmatulin et al. 1991 ; Duong Ngoc Hai 1994, 1996, and etc. ). The primary objective of the reservoir study is t o simulate the performance of reservoir and, based on this , predicting and possibly finding the ways and means for increasing ultimate oil recovery. The classical reservoir engineering deals with the reservoir based on gross average basis (tank model) and cannot take into account adequately the variations of reservoir and flui d characteristics in space and time. Reservoir simulation by computers allows more detailed study of reservoir by dividing it into a number of blocks and applying fund amental equations for in porous media to each block (Bear 1987; Khalid 1979; Calvin 1990). In the world, reservoir simulators are developed and .