Modelling of water-oil flow in reservoirs including effects from gravity, capillary pressure and water rock chemistry

Master's thesis in Petroleum engineeringIn this work we use mass balance equations to arrive at a classical description of the Buckley-Leverett equation for two phase flow in a one dimensional porous medium. Through the use of explicit numerical techniques we study the solution of immiscible displacement in an oil-water system. In particular, we study the effect of viscosity, relative permeability, wettability, capillary pressure and gravity. We show that all of these effects are important for oil recovery processes. These type of models, are very useful when investigating typical reservoir flow behaviour, and when evaluating different enhanced oil recovery (EOR) techniques. In this case, a low salinity model is used to study different ‘low salinity’ brines in a immiscible displacement process. This model extends the Buckley-Leverett formulation by incorporating a multiple ion exchange (MIE) process. We show that for certain brine compositions, we are able to model positive low salinity effects and thus increase oil recovery