Numerical Modeling Of Oil Migration Using The TOUGH2

Oil has always been a very important source of energy, whether it is on people’s production and life, or for the country’s economic strategy. The increasing difficulty and risk of the oil exploration require people to further deepen the understanding of the law of oil migration and accumulation, especially the law of oil secondary migration and accumulation, and measure the trend of oil migration and accumulation in the exploration area as accurately as possible, in order to reduce exploration risk. The secondary migration and accumulation of oil has been the focus of attention of many researchers, but also the difficulty of petroleum geology studies. Traditionally, the study of secondary oil migration and accumulation is mainly through physical analog. However, physical analog is difficult to characterize the actual geological conditions accurately; and is expensive, complicated to be operated, not flexible enough, repeatability low and so on. The numerical modeling is dynamic analysis highly integrated with theories, methods and techniques, and it better reflects the advantage of solving complex geological problems in the study of petroleum migration than the physical analog. The advantage of numerical modeling will be more obvious with the development of computer technology.Firstly, this paper introduces a three-dimensional numerical modeling program TOUGH2, which could model multicomponent multiphase flow and heat transfer in porous media or fractured media in non-isothermal or isothermal conditions. The EOS8module in the TOUGH2is used to build a two-dimensional numerical model of a cross-sectional profile for modeling three phase flow of water-gas-oil in the open-fracture fault system, and the feasibility of the TOUGH2used to model the migration of oil is discussed, compared with physical analog experiments. A two-dimensional numerical model of a cross-sectional profile of the central block of Caspian Basin for modeling three phase flow of water-gas-oil is built through the TOUGH2, and the law of migration and accumulation of oil in the different fault nature conditions is analyzed. The results show that, the TOUGH2can be used to characterize the migration and distribution of oil in the open-fracture fault system; compared with physical analog experiments, numerical simulation methods such as TOUGH2are cost-effective and operation-flexible and can be applicable to modeling three-phase flow of water-gas-oil under a variety of complex conditions; the numerical model of oil migration in the central block of Caspian Basin reveals the path of advantage of oil migration and the possible area of oil gathering, but also reveals the influence of the different nature of the fault on migration and accumulation of oil.