Biswal, Sibani L.Hirasaki, George J.2020-04-272021-05-012020-052020-04-23May 2020Zhang, Leilei. "Foam EOR for Carbonate Reservoirs: from Lab Evaluation to Pilot Field Test." (2020) Diss., Rice University. <a href="https://hdl.handle.net/1911/108418">https://hdl.handle.net/1911/108418</a>.https://hdl.handle.net/1911/108418Enhanced oil recovery (EOR) techniques have changed how we recover oil more efficiently. The injection of surfactant foamed gas can mitigate the poor sweep efficiency caused by reservoir heterogeneity, density differential, and viscous fingering effects. How to tune foam strength, foam rheology, and foam collapse properties depends highly on reservoir conditions. This dissertation provides comprehensive study of foam transport design in porous media including formulation screening, lab scale evaluation, pilot field test, and produced emulsion treatment. These studies provide a full life cycle analysis for EOR foam. Low surfactant adsorption is required to control the cost of successful foam applications. In carbonate reservoirs, cationic surfactants and nonionic surfactants usually have low adsorption compare to more commonly used anionic surfactants. The studied switchable cationic surfactant (TTM) adsorption is low on pure carbonate surface, but relatively high on natural carbonate surface due to the presence of siliceous minerals. The diamine surfactant adsorption is dominated by electrostatic attraction. Lower adsorption can be achieved by modifying the electrostatic interaction by: (a) decreasing the solution pH, (b) adding ions for charge screening (effectiveness: monovalent<divalent<trivalent), and (c) introducing sacrificial polymer. Workflows are proposed for gas mobility control and foam diversion design in carbonate reservoirs. For the gas mobility control design, the target reservoir is under high pressure, high temperature, and ultrahigh salinity, which challenges the foaming surfactant stability and foam strength. The formulation (CTM) is systematically evaluated including solubility, thermal stability, adsorption, phase behavior, and flow experiments to detect oil and wettability effect on foam transport. The importance of residual oil and wettability for foam generation and foam strength is investigated. In a water-wet core, the CTM foam has high apparent viscosity in the presence of residual oil. However, strong foam cannot be generated in a core that is made oil-wet. The minimum pressure gradient (MPG) for weak foam generation is observed. In the foam diversion design, miscible fluids are diverted by a foam “blanket” near the wellbore to avoid re-saturating the region that has been displaced by an earlier pilot. Different from the foam mobility control design, the diversion foam contacts the injected light hydrocarbons rather than the oil and gas in place. A nonionic surfactant (G12) which has good tolerance to light hydrocarbons is studied. Strong foam is generated when the superficial velocity is above 1 ft/D with and without residual oil. The foam shear thinning behavior was observed to be independent of rock permeability and residual oil. Thus, a lab correlation can be used for prediction of foam strength in the field. The foam quality scan data is fitted with STARS model, providing parameters for a reservoir scale simulation. Experience gained from a foam pilot test is also summarized. For a foam project scale-up, the successful surfactant injection, low oxygen level, proper mix of chemicals, and wellhead sample foamability are required for quality control. In the pilot, an injection process involving surfactant alternated CO2 gas injection with the intention of generating foam in situ to improve contacting of the heterogenous reservoir. Finally, many surfactant EOR processes lead to emulsion production problem. The produced emulsion issue is addressed. The emulsions in the oil phase can be destabilized and separated to oil and water by gravity. The oil dispersion on the water phase can be treated with magnetic nanoparticles in a magnetic field. In conclusion, this thesis develops workflows for the successful implementation of foam for EOR. Specially, we examine from the surfactant scale to a field scale foam pilot test, which advances the application for foam EOR.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.SurfactantCO2FoamEOREmulsionNanoparticle.Thesis2020-04-27