Foam injection has been proven to be an efficient technique for EOR applications, stimulation operations and profile control. However, foam is known to have low stability and poor oil tolerance but adding polymer is reported to be an efficient way to improve such foam stability. An extensive study has been undertaken with different surfactants (foaming agents) and polymers to screen out the surfactant/polymer combinations providing the highest foam stability.
We performed a systematic study consisting of static tests (foamability, stability) from which we selected two surfactants (nonionic and anionic) and two polymers (nonionic and associative polymer) expected to highly improve foam performances. Core-flood experiments were performed in high-permeability sandpacks in successive sequences starting with foam propagation, followed by a water flow and then an oil backflow. The Resistance Factor (RF) has been measured for each flow sequence.
Based on our experiments, polymer-enhanced foams is shown to be a promising way for profile control during waterflood and recommendation of use of an associative polymer instead of a classical nonionic polymer is discussed.