THE ROLE OF OIL-IN-WATER EMULSION COMPONENTS ON SANDSTONES PERMEABILITY

This work studies the stability of oil-in-water emulsions and proposes a new methodology to evaluate the impact of different emulsion's components (sodium chloride, surfactant, and oil) on permeability decline during the injection into natural rocks. Stable emulsions were obtained by varying surfactant and oil concentrations and stirring speed. Emulsions, proven to be stable for more than 24h, were used in coreflooding tests. First, coreflooding experiments were conducted by injecting brine, which provided a permeability reduction of 7% and 20% in rocks measuring approximately 20mD and 120mD, respectively. Then, a surfactant solution was injected, resulting in a decline in permeability from 17 to 23% in the studied scenarios. Finally, emulsions with 0.05 and 0.01wt% oil concentrations were injected, and permeability was reduced to around 65% of its original value in low permeability rocks. Results show that damage due to oil droplets retention was intensive in the scenarios studied.