Fundamentals of CO2-Hydrocarbon Interactions for CO2 storage with EOR/EGR in offshore reservoirs: modeling, numerical methods and upscaling
2016 – 2019
Storage of carbon dioxide (CO2) in geological formations is a means to reduce atmospheric emissions of this greenhouse gas. CO2 storage combined with enhanced oil recovery (EOR) or enhanced gas recovery (EGR) is perceived as the most cost-effective method of disposing captured CO2 emissions. It has been performed for many decades in the US and Canada, but traditionally with a focus on hydrocarbon recovery. On the Norwegian Continental Shelf, CO2 storage will be emphasized in order to meet ambitious climate targets set in Norway and Europe. Project CHI will carry out basic research on CO2-hydrocarbon interactions for CO2 storage in oil and gas reservoirs that could fundamentally alter the ability to recover trapped hydrocarbons while simultaneously maximizing CO2 storage. The project focuses on two processes, convective mixing and wettability, which were chosen because recent experiments show compelling results that may have a significant, yet still largely unknown, impact on field-scale fluid flow (recovery) and trapping (storage). Convective mixing of CO2 in oil is caused by density variations in CO2-oil mixtures. It increases the mixing of injected CO2 with the oil, and this also modifies the mobility of the oil (recovery). Wettability is the preference of one fluid to be in contact with the rock surface over another. This impacts the capacity of the rock to trap CO2. However, wettability can change over time. New mathematical models for CO2 storage with EOR/EGR in heterogeneous reservoirs will be developed to properly include convective mixing and dynamic wettability effects. The resulting advanced knowledge will be integrated into field-scale simulators and used to investigate expected impacts on CO2-EOR/EGR scenarios. A practical outcome of the project will be assessment of reservoir conditions under which oil and gas recovery can be improved while simultaneously increasing storage potential.