Coreflood experiments with surfactant systems for IOR: Computer tomography studies and numerical modelling

Alvestad, J., Gilje, E., Hove, A.O., Langeland, O., Maldal, T. and Schilling, B.E.R., 1992. Coreflood experiment; with surfactant systems for IOR: Computer tomography studies and numerical modelling. In: O. Vikane (Editor), Enhanced Oil Recovery. J. Pet. Sci. Eng., 7: 155-171. This paper addresses the dynamic behaviour of surfactant systems for IOR-applications in terms of phase behavior and coreflood recovery processes. Extensive measurements of phase behaviour have provided a good characterization of the phase diagram of a brine, surfactant and heptane system. The surfactant system does not require any cosurfactant to obtain middle-phase microemulsions. Tertiary recovery surfactant coreflood experiments have been performed and the dynamic process in the core have been studied using computer tomography (CT). Effluent analysis have also been performed. A new phase-behavior-model based on direct interpolation of experimental data combined with correlations has been developed and used for the modelling of the phase behaviour of this overall three-component system (brine,heptane and surfactant). A tertiary coreflood recovery test has been simulated using a compositional chemical flooding simulator with the new phase-behaviour model. The CT-analysis reveals information of the surfactant flooding mechanisms which is important for consistent numerical modelling of the flooding process. The numerical simulations reproduce the main features of the flooding process. Sensitivities illustrate the effect of important and uncertain parameters.