Functional compounds of crude oil during low salinity water injection

Due to the intrinsic complexity of crude oil, the advanced chemical compositional analysis would be required to detect the crucial interactions that may take place between water and crude oil during low salinity water injection (LSWI). In this study, a series of analytical techniques were combined to discover the functional compounds of crude oil contributing to low salinity water effect (LSE) during LSWI. The Fourier Transform Infrared (FT-IR) analysis and Fourier Transform Ion Cyclotron Resonance Mass Spectroscopy (FT-ICR MS) were deployed to characterise the oil/water interface of a chosen crude oil with a high potency toward formation of water microdispersion. Using the negative and positive electrospray ionisation modes (-ESI and +ESI, respectively), acidic compounds with aliphatic nature and asphaltene molecules were determined to be the most functional compounds at the interface promoting the spontaneous formation of water-in-oil microdispersion. These species are key to designing any waterflood operation in oil reservoirs.

Automated summary

This study identified the functional compounds in crude oil that contribute to the low salinity water effect during water injection. Acidic compounds with aliphatic nature and asphaltene molecules were found to promote the formation of water-in-oil microdispersion at the interface, crucial for designing waterflood operations in oil reservoirs.