Nuclear magnetic resonance experiments on foam flooding and evaluation of foam dynamic stability

Abstract

A visualization experimental method of foam flooding was developed by combining nuclear magnetic resonance (NMR) and traditional core flooding method. On this basis, a new method to evaluate the dynamic stability of foam in the core during displacement process was established. Using this method, the displacement characteristics and dynamic stability of foam of S-2 (the main component is sodium lauryl sulfate) and S-NP-2 (the main components are sodium lauryl sulfate and silica nanoparticles) in two different displacement modes, i.e. direct foam flooding and foam flooding after water flooding, were studied. The results show that the NMR images and the T2 (transverse relaxation time) spectrum reflected the displacement characteristics. The flooding efficiency of S-2 and S-NP-2 after water flooding was increased by 18.05% and 25.68% and reached 63.72% and 67.50% respectively at last, higher than direct foam flooding. The same foam system had better stability in foam flooding after water flooding than in direct foam flooding, and foam S-NP-2 is more stable than foam S-2 under the same displacement mode. Key words: foam flooding, flooding experiment, flooding efficiency, nuclear magnetic resonance (NMR), foam stability, evaluation method