Mobilization of the residual oil by surfactant flooding involves a complex process not fully understood. The injected surfactant slug interacts with formation brine, oil, and the mineral surface. Usually, only the effluent production is available for analysis and history matching of the surfactant core floods. In this paper the analysis is enhanced by measuring the in situ saturation profiles directly during the displacement.
In order to analyse the fluid propagation during a surfactant flood, we have measured the one dimensional saturation distribution along the core as a function of time. The fluid saturation profiles are analysed by a moveable Germanium detector, measuring the radiation from a nuclear tracer added to the brine phase. The dynamics of the saturation profiles are obtanied by scanning the core several times during the displacement. The measured saturation profiles are found to correlate well with the observed effluent production.
We focus on the description of recovery improvement, how the local saturations are developing during the surfactant floods and how well numerical simulations match the results from the experimental displacements.