Global energy strategies must reflect climate and societal challenges. Technologies must be developed to reduce emissions and improve energy efficiency. Carbon capture, utilization and storage (CCUS) is a readily available technology for substantial emission cuts for many industries. CCUS can involve capturing CO2 emissions from industrial sources and utilizing the CO2 for simultaneous energy production and CO2 storage in subsurface reservoirs. The aim is to reduce the life-cycle emissions of fossil fuels and provide an economic pathway to decarbonizing our energy system.
A major part of CCUS is CO2 enhanced oil recovery (EOR) and CO2 storage. CO2 EOR can store the gigaton volumes of CO2 needed to mitigate climate change, while generating a revenue for the industry; a crucial criteria for wide-spread implementation of CCUS. However, a major problem during CO2 injection is the low density and viscosity of CO2. These adverse properties can restrict energy production and CO2 storage efficiency. Foam can mitigate unfavorable CO2 properties to improve energy production and increase CO2 storage potential. CO2 foam injection involves injecting a foaming agent with CO2 to reduce its mobility. Surfactants are often used to stabilize foams but they can breakdown in the reservoir due to adsorption, the presence of oil, and elevated temperatures and salinities. Thus, their ability to reduce CO2 mobility can be limited. The addition of nanoparticles to the surfactant-stabilized foam can increase its strength and stability. Therefore, this project includes nanoparticles in the surfactant-based foam for increased foam performance.
To date, the project has utilized state-of-the-art methods and tools including high pressure/high temperature core-scale experiments, including in-situ imaging with PET/CT, and numerical modeling. The project employs, one PhD student and one Researcher who have combined to publish four scientific papers. In addition, five scientific talks have been delivered at international conferences. Within the next year it is expected that advanced in-situ imaging techniques will continue to be utilized to visualize foam flow in porous media. In addition, numerical modeling work will upscale the measurements from the lab studies. It is expected that this will results in a least two additional publications. The overall goal is to develop new knowledge and upscaling strategies to reduce emissions while providing low-carbon energy for a transition to a net-zero society.
Norway has more than 23 mature waterflooded reservoirs with ca. 2 400 million Sm3 residual oil as an EOR target. In gas EOR, the low density and viscosity of injected gas results in viscous fingering, gravity override, and flow in thief zones causing poor reservoir sweep efficiency and low oil recoveries. Foam for mobility control can improve gas EOR performance by mitigating gas injection challenges. Foam injection involves injecting a soap (surfactant solution) with gas, such as carbon dioxide (CO2), where simultaneous CO2 storage assists in reducing GHG emissions. Using nanoparticles in conjunction with surfactants can increase the stability of mobility control foams. However, there is a knowledge need to improve the understanding of size-dependent NP CO2 foam dynamics. Thus, this project proposes to develop new knowledge and upscaling strategies by performing pore- and core-scale experiments and numerical modeling to understand NP CO2 foams at reservoir conditions.
A key innovation of this project is the use of combined positron emission tomography (PET) and computed tomography (CT) to visualize in-situ fluid saturations and characterize NP CO2 foam systems in the laboratory for qualitative and quantitative analysis of foam’s impacts on CO2 mobility, fluid displacement, and nanoparticle retention and concentration. Advanced laboratory techniques coupled with multiscale modeling provides an improved methodology to further the current understanding of foam dynamics at multiple scales, while establishing better tools for predictive modeling of NP CO2 foam processes. The project will utilize expertise developed in two ongoing NFR/CLIMIT projects (249742 and 268216), which include onshore CO2 foam field pilots and investigation of NP foam at harsh reservoir conditions. The overarching goal is to optimize CO2 foam systems to prepare for an onshore field pilot in collaboration with upcoming funding calls from USDOE and NFR.
