Strontium-based low salinity water as an IOR/EOR method: Oil-brine interaction

Abstract

Strontium-based injection water for enhanced oil recovery has been neglected due to the low solubility of the cation in water. However, challenging reservoirs like those in the Brazilian pre-salt region demand non-conventional solutions to improve oil production. This work shows for the first time that the strontium cation in low salinity water solutions shall be henceforth considered as a potential component in the development of enhanced/improved oil recovery (EOR/IOR) studies. Acidic and non-acidic model oils and real crude oils from Brazilian post-salt and pre-salt fields were used for this study. The oil/brine interfacial tension and viscoelastic properties of the interfacial films were measured by an ascendant drop tensiometer. The results showed that strontium presents the highest interfacial activity among the other alkaline-earth metals. Also, the strontium-based low salinity water produced the most elastic interfacial film, which is desired for the improvement of oil volumetric sweeping promoted by water flooding. Nonetheless, it is worth highlighting that further studies including core flooding experiments must be performed to assess the strontium effect on the crude oil outflow through reservoir pores as well as the influence of water/oil/rock interactions upon it.