Impact of natural convection and diffusion on variation of oil composition through a fractured model

Abstract

The first step to study oil reservoirs is determination of reservoir fluid composition in both horizontal and vertical directions. In this research, fluid composition distribution is investigated as a result of diffusion and natural convection in a naturally fractured model. A two-component single phase fluid and a rectangular two-dimensional fractured oil reservoir with a known temperature profile are used in this study. MATLAB software is exploited to solve governing equations, numerically. According to results, thermal diffusion has the greatest impact on the variation of fluid composition, followed by pressure and molecular diffusions, respectively. Moreover, it is found out that even a small convection would change the fluid composition distribution, considerably. Fluids tend to flow through the fracture due to its high permeability; therefore, a counterclockwise convective cell would flow in the reservoir.