The mobilization of ASP emulsions and the existing of alkaline scale played important effect on fluid flow characteristics through porous media, which exert import effect on the simulation and prediction of ASP flooding process.
The previous studies were carried out to observe alkaline dissolution and precipitation reaction, emulsion rheology, emulsion drop capture, and stable emulsion flowing through capillary tube. However, few studies had been carried out to quantitatively describe emulsion and alkaline scale effect on enhanced oil recovery. This paper aims to improve simulation accuracy by description of physical chemical reaction processes, and enhance simulation speed and stability by improved solution.
The prediction model of permeability and porosity alternation caused by alkaline scale was established, and emulsion flow mechanisms in porous media including emulsifying startup, emulsifying entrainment, emulsion rheology and emulsion droplets capture was mathematically described. On this basis, an improved ASP flooding numerical simulation model incorporating emulsification and alkaline scale was established. In order to better solve the above model, IMPLICIT difference scheme and improved Parallel computing method IBiCRSTAB was proposed. The simulator was validated by comparing the simulation results with the results from linear core floods performed in the laboratory.
The ASP flooding process was simulated on geological model of DaQing Oilfield. The simulation result shows that emulsification role is favor of further improvement of displacement efficiency on middle-high permeability layer, moreover, it could enhance sweep efficiency of low-middle layer. Alkaline scale could decrease inject capability of injection wells and produce capability of oil wells, and bring higher formation damage for low-permeability layer. The proposed IMPLICIT method is more stable and efficient than the traditional methods of IMPES, and the IBiCRSTAB method could significantly improve efficiency 66% for large-scale simulations.