A Novel Enhanced Oil Recovery (EOR) Technique in the Bakken Formation Using Magnesium-Doped Class C Fly Ash Nanoparticles (Mg-FANPs) in Supercritical CO2 Foam

Abstract I present a novel Enhanced Oil Recovery (EOR) process in North Dakota's Bakken Formation by integrating Magnesium-doped Class C fly ash nanoparticles (Mg-FANPs) within a supercritical CO₂ (scCO₂) Foam via huff-and-puff (HnP) injection. Targeting the carbonate dominated Middle Member (limestone, dolomite and Calcite) in the Williston/Three Forks Basin. This method leverages on the pozzolanic, mechanical and geo-mechanical properties of Mg-doped FANPs (<50 nm, >5000 psi crush strength) and scCO₂ foam (0.2 cP, 70% gas fraction) to achieve 22-37% recovery of original oil in place (OOIP), with an optimization potential to 39-50% OOIP, comparatively surpassing the conventional CO₂ HnP benchmark of 7-15%. Analytical models enclosed in this proving include; Einstein Stokes (diffusion-based coefficient), mobility ratio (with relative permeability), capillary number (oil displacement), CaCO₃ precipitation kinetics (fracture stabilization), and foam stability (half-time decay) is evaluated using Bakken-specific data at (5% porosity, <0.05 mD permeability, <0.2-0.4 cP oil viscosity, at 5000 psi, and 240°F). This project highlights a net present value (NPV) of $342 billion over 20 years, recovering an estimated 22-50 billion barrels from the Williston oil reservoir. The Buckley-Leverett model, adapted from Pope's fractional flow theory, confirms Mg-FANPs superiority with a residual oil saturation (Sor) of 0.28 and effective viscosity of 0.2 cP. Further assessments with recent studies in novel nanoparticles and insights on improving foam stability in CO₂ HnP, refracturing methods, and surfactant alternating gas methods (SAG), demonstrate superior performance and cost-effectiveness of the Mg-FANPs ($0.2-$0.7/kg FANPs), utilizing North Dakota's abundant fly ash resource. Recent studies on fly ash Nanoparticles and scCO₂ interactions validate this method's efficacy in enhancing foam stability, mitigating mechanical degradation, controlled precipitation, and reinforcing the novelty of this Bakken-tailored approach for sustainable CCUS-integrated in the EOR process.