A Model for Prediction of Recovery and Pressure History for 2-D Displacement of Oil Through Porous Media by Gas/Surfactant Conference Paper uri icon

abstract

  • ABSTRACT The problem of predicting recovery and pressure behavior during gas/surfactant solution flooding is too complex to be treated analytically with the current state of knowledge. In the early stages of such displacements, the gas and surfactants are macroscopically dissociated and segregated, each flowing in separate channels. The in situ generation of foam does not seem to initiate until a certain mass of surfactant has been injected. Frontal advance theories such as the Buckley-Leverett theory or the Dietz model assume the injected fluid to be single phase, homogeneous, and non-reactive. Since these criteria are not met by the flow of gas and surfactant solution, these theories fail to accurately predict the recovery performance of such displacements. Based on the observations made during a series of experiments on a scaled-model, a semi-analytical model is proposed to predict the oil recovery and pressure history from two-dimensional (x,z) systems undergoing gas/surfactant injection. The model is based on the concept of a combination flood, in which gas/foam and surfactant solution flow in separate gravity tongues. The gas/foam displacement is assumed to follow the Buckley Leverett theory, whereas the surfactant displacement follows the Dietz model. The displacements through these tongues are mutually dependent and, therefore, these theories are combined at each stage. The predictions from the model gave a good match with the experimental results for a fairly broad range of operating conditions. The semi-analytical approach adopted in developing the combination drive model has potential for application to certain other types of frontal behaviors.

publication date

  • 1986