EVALUATION OF COc-PHILIC FOA\1 SURFACT ANTS AS \10BILITY CONTROL AGENT

The focus of this thesis is on the evaluation of C02-philic surfactants for
application in foam assisted C02-WAG injection, under immiscible conditions of a
Malaysian reservoir case. The surfactant blending and addition of C02-philic
functionalities in surfactant structure is investigated for this reservoir to enhance C02
mobility control, and to mitigate SAG operational problems in terms of foam-oil
tolerance, limiting water saturation requirement, and sensitivity to reservOir
conditions. The C02/oil system phase behavior analysis in tenns of viscosity
reduction, IFT reduction, and C02 dissolution in immiscible conditions of the
reservoir were experimentally investigated. The structure-property analyses of COr
philic surfactant blends were perfonned in terms of C02 dissolution in aqueous phase,
effect of surfactant on Oil/Water and Gas/Water interfaces, foamability and foam
stability in the presence of oil at reservoir conditions. The theoretical entering,
spreading, and bridging coefficients model was utilized for surfactant screening in
tenns of foam stability in the presence of oil at desired pressure range and temperature
conditions. Foam-induced C02 mobility control for different surfactants was tested in
coreflood system to correlate MRF values and interfacial behavior of surfactants.