Advanced Ion Management to Improve Oil Recovery in Oil-Wet Carbonate-Sandstone Composite Reservoirs

Alhuraishawy, Ali K. (Missan Oil Company / Reservoir and Fields Development Directorate) | Bai, Baojun (Missouri University of Science and Technology) | Wei, Mingzhen (Missouri University of Science and Technology) | Al-Bazzaz, Waleed H. (Kuwait Institute for Sciencefic Research)

OnePetro 

Abstract

Waterflooding with different inonic composition called advanced ion management which play a role with ionic composition of injected water to enhance the oil production. In the last decate, many studies pointed out that the composition of injected water could changes rock wettability during waterflooding. The main purpose of this study is to evaluate the effects of SO4 and low salinity water on improving oil recovery in oil-wet carbonate reservoirs. Sulfate ion concentration, low salinity water, rock composition, porosity, and permeability were examined using a designed model. Typical seawater, increase SO4, two and three times in the seawater, and low salinity water that had been diluted 10 and 100 times were applied as waterflooding processes with three different average matrix permeability. Oil recovery factor improved as sulfate ion concentration increased and water salinity decreased by changing core wettability with greater water-wet conditions. Morover, the diluted seawater has more effect than sulfate ion concentration when a carbonate core has a few percentage of silica. Sulfate ion concentration performance increased with porosity and temperature, and the dilute seawater showed more effect at high temperature. Increased sulfate ion concentration followed by diluted sea water with present silica in the core composition might be a viable technique to improve oil recovery in the carbonate reservoir. The experimental results validated by field-scale simulation study and provides deep insight into understanding of advanced ion management performance.