Folasade Ayoola

All Publications

• Techno-economic analysis of capture of California oilfield CO2 emissions with produced water Ayoola, F. Stanford University. 2020

  Abstract

  Fossil fuels remain the major source of primary energy globally, making emissions reductions from fuel combustion critical on the path to the decarbonization of energy. More than half of California’s oilfields utilize steam flooding or cyclic steaming for enhanced oil recovery, producing significant quantities of brine. This project explores the techno-economic feasibility of capturing produced CO2 emissions from a California oil production facility in Orcutt Hill, Pacific Coast Energy Company (PCEC), using produced water, given the large available volumes from the site due to high water-oil ratios from oil production. The water capture project is coupled with the injection of resulting carbonated water into oil reservoirs to produce marginal oil recovery benefits. This technology is then compared to the conventional alternative for capture, which utilizes monoethanolamine as solvent in an energy- intensive solvent-regeneration process, with the injection of captured CO2. Costs for both proposed projects at the PCEC facility are estimated by designing the capture systems using the Aspen Plus commercial process simulator, and estimating project costs using cost factors on equipment cost estimates, given simulated equipment sizes and specifications. Benefits are assumed to be obtained from improved oil recovery by either carbonated water injection or CO2-flooding, as well as existing state and federal tax incentives for emissions mitigation. The net present value of net benefits for both projects are negative, with that of the MEA capture system estimated at approximately ($14million) or ($23.50/tonCO2 captured) and that of the water capture system estimated at ($40million) or ($48.50/tonCO2 captured). In the former, capital cost estimates greatly influence investment outcomes, while in the latter, water treatment costs are prohibitively high and limit project viability. However, net benefits estimates are sensitive to changes in prevailing market interest rates, and even more so to the proven marginal enhanced oil recovery improvement, among other factors. Results show the MEA project being more viable, although one advantage of the water capture project over the MEA capture project that is difficult to quantify and yet particularly pertinent, is the CO2 leak risk reduction.