CO₂ Foam Using non-ionic Surfactants : For Increased Storage Capacity and Oil Recovery

Large-scale carbon capture and storage is needed to achieve the target set forward by the Paris agreement; to limit global warming to 1.5 °C. The primary obstacle for implementing large-scale carbon capture and storage is the high economical cost. Utilization of CO₂ as a commodity in production processes, commonly called carbon capture and utilization (CCUS), can establish a CO₂ value-chain and provide economic incentives. A promising use of CO₂ is for enhanced oil recovery (EOR). Additional oil can be recovered from oil reservoirs by injecting CO₂; simultaneously, CO₂ is stored in the subsurface. CO₂-EOR is field-proven, however, it has primarily been implemented using non-anthropogenic CO₂. The potential economic revenue by establishing a CO₂ value-chain with CO₂-EOR, using anthropogenic CO₂ have yet been insufficient for the industry. CO₂-EOR has inherent challenges due to the viscosity and density differences between reservoir fluids and the injected CO₂, potentially leading to poor sweep efficiency. Poor sweep efficiency is detrimental to oil recovery and CO₂ storage. Providing technological solutions that tackle the sweep efficiency issues can potentially make CO₂-EOR feasible and catalyze the implementation of large-scale carbon capture and storage. Foam is a technological solution that decreases the mobility of CO₂ and increases sweep efficiency. This thesis presents a multi-scale investigation of foam for CO₂ mobility control stabilized using non-ionic surfactants. The study includes investigations from pore-scale foam dynamics to field-scale implementation of CO₂-foam injection, with an emphasis to produce oil from mature field with a reduced carbon footprint. The thesis consists of five chapters. Chapter 1 provides an introduction and a rationale for the research questions addressed in this thesis, whereas Chapter 2 provides a theoretical background of fundamental concepts of foam in porous media. Chapter 3 summarizes the experimental methods and clarifies how the experiments relate to each other. Chapter 4 presents key findings from the five publications, emphasizing synergetic results from published work, and is organized into individual foam-subjects.