Simulation and Assessment of Surfactant Injection in Fractured Reservoirs: A Sensitivity Analysis of some Uncertain Parameters

Abstract

Fracture reservoirs contain most of the oil reserves of the Middle East. Such reservoirs are poorly understood and recovery from fractured reservoirs is typically lower than those from conventional reservoirs. Many efforts have been made to enhance the recovery and production potential of these reservoirs. Fractured reservoirs with high matrix porosity and low matrix permeability need a secondary or EOR technique to achieve the maximum production. One of the effective EOR approaches is surfactant flooding, which reduces interfacial tension and alters wettability. Due to the complexity and uncertainty associated with such reservoirs, implementing a simulation and numerical analysis is primarily necessary to evaluate the effect of key engineering parameters on ultimate reservoir performance. This study assesses and provides a good insight into surfactant injection into fractured reservoirs using ECLIPSE software as a numerical simulator. The influences of fracture-matrix permeability ratio, initial water saturation, and the number of grids on reservoir performance were assessed and a sensitivity analysis was carried out. This study takes surfactant-related phenomena such as adsorption, surface tension reduction, and wettability alteration into account. The simulation results demonstrate that fracture-matrix permeability ratio is an important screening quantity for the selection of surfactant flooding as an EOR agent and that uncertainty in the initial water saturation of matrix has a great influence on the simulation outputs.