The CO2 foam which has been used for oil and gas production, suffers from instability in the presence of crude oil. This problem is even more severe in high salinity environments. Designing a system that works in that environment and in the presence of crude oil is very crucial. On the other hand, huge amounts of water are being produced associated to oil and gas production. Handling this water needs considering multiple options including disposal, treatment and re-injection. Produced water disposal is strongly restricted by environmental regulations. The treatment of produced water needs treatment technologies not available in most states. Re-injection of produced water into the reservoir requires finding an optimized system of chemicals which are compatible with the produced brine. The objective of this project is to design a chemical system which can tolerate high salinity produced water and, in the presence of crude oil, make the foam system used for enhanced oil recovery applications environmentally friendly. In this study, we investigate the performance of a foam system with surfactant and addition of polyelectrolyte and polyelectrolyte complex nanoparticles (PECNP) in various produced water salinity. The most optimized solution of nanoparticle is developed in high salinity produced water. The rheological property of the foam, the stability and durability of the foam with and without the presence of crude oil are measured and compared as the water salinity is varied. Furthermore, the effect of nanoparticle on the viscoelasticity of the interface is studied and finally, a set of core flood experiments are conducted to observe the incremental oil production. It is found that foam stability and durability is deteriorated when water salinity is increased. By addition of polyelectrolyte and PECNP in the system, however, the foam stability and durability was improved even in high salinity water with or without crude oil in the system. Also, the effect of nanoparticles on the viscoelasticity of the interface shows improvements due to the addition of polyelectrolyte complex nanoparticles to the surfactant solution. The core flood experiments in the presence of crude oil show promising results for the CO2 foams generated by nanoparticle-surfactant system.

CO2 foam: Stability improving in high salinity produced water

254th National Meeting (2017)

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