Numerical simulation of mineral precipitation in hydrocarbon reservoirs and wellbores

Abstract

Mineral precipitation or scale formation in reservoirs, injection, and production wells is recognized as an obstacle for hydrocarbon recovery. Significant production drops and injection losses can occur as a result of mineral precipitations during water flooding. Several attempts have been made to better understand the underlying mechanisms of mineral precipitation through experimental and numerical simulation studies. In this study, we have investigated the impact of mineral precipitation on oil recovery and injection performance of a synthetic reservoir through numerical simulations. Additionally, we studied the scaling (scale formation) tendency and precipitation amount of various minerals in wellbore based on water compositions from the Gulf of Mexico. We also studied the impact of mineral precipitation on water flooding efficiency by analyzing saturation profiles of the injected water. Our results indicate that the reservoir experiences severe damage with respect to ultimate recovery, and injectivity loss due to the scale formation. Water saturation profiles reveal that mineral precipitation in reservoirs not only leads to non-ideal displacement of the in-situ hydrocarbon, but also causes earlier water breakthrough. The results of mineral precipitation in wellbore show that while some minerals (e.g., calcite) precipitate in large amounts, other minerals (e.g., gypsum) remain in equilibrium with the flowing brine in wellbore under the same pressure and temperature conditions.