Coupling of a Reservoir Simulator with Geochemistry for Chemical Enhanced Oil Recovery

Abstract

AbstractChemical enhanced oil recovery (CEOR) techniques are some of the most effective and economical tertiary oil extraction processes. As a key tool for the recovery performance evaluation, reservoir simulation plays an instrumental role in the expansion of the field application of CEOR. However, their framework models essentially the physical aspect of the recovery process. The significant influence of geochemical interactions on the recovery performance remains largely unintegrated. In this study, MATLAB Reservoir Simulation Toolbox (MRST) was coupled with PHREEQC for improved modeling and simulation of polymer flooding and low salinity water flooding (LSWF). The MRST’s polymer model was extended for multi-phase chemical transport by the addition of chemical species in wells boundary conditions, and phase relative permeabilities were modified to account for the wettability alteration effect of the flooding process. In validation, the coupled model showed a good match against PHREEQC in a simulation of a single-phase carbonate core low salinity water flooding (LSWF). It also validated well in the case of matching high salinity experimental results. A demonstrative application of the coupled model in the simulation of LSWF showed 27% maximum incremental oil recovery with a 3.3 mean water-oil ratio (WOR). Furthermore, combining LSWF with polymer flooding achieved the same recovery potential but with much lower water production (0.2 WOR) and doubled production period. These results preliminarily indicate that polymer flooding and LSWF could be combined for at least 27% additional original oil in place (OOIP) recovery with no more than 1 WOR in carbonate reservoirs. However, as this recovery performance evaluation was done in 1D, further work on the coupled model includes improving it for multi-dimensional application.