BibTeX:

@article{IJIRSTV3I11079,
     title={Critical Role of Wettability Alteration in Improved Oil Recovery by Low-Salinity Water in Sandstone Rock - A Theoretical Approach},
     author={Harsh Anjirwala},
     journal={International Journal for Innovative Research in Science & Technology},
     volume={3},
     number={11},
     pages={134--143},
     year={},
     url={http://www.ijirst.org/articles/IJIRSTV3I11079.pdf},
     publisher={IJIRST (International Journal for Innovative Research in Science & Technology)},
}

Low Salinity Flooding (LSF) is an emerging technology to improve oil recovery for both sandstone and carbonate reservoirs. Low salinity water injections for oil recovery have shown seemingly promising results in the case of clay-bearing sandstones saturated with asphaltic crude oil. Testing over the last 20 years has shown that incremental oil recovery using this method can be potentially significant, with sandstone reservoirs showing an incremental oil recovery range of between 5% and 30% of original oil in place (OOIP).The underlying mechanisms behind this phenomenon is not well understood, but many researchers have suggested that it is related to complex crude oil/brine/rock interactions. In recent years, positive results have been presented regarding the combination of low salinity water and surfactant injection. The answer requires a thorough understanding of oil recovery mechanism of low salinity water injections. Numerous hypotheses have been proposed to explain the increased oil recovery using low salinity water, including migration of detached mixed-wet clay particles with absorbed residual oil drops, wettability alteration toward increased water-wetness, and emulsion formation. The mechanisms of enhanced recovery are considered to be decrease of residual oil saturation and alternation of rock wettability. In addition, the mobility control mechanism due to induced fines migration by low salinity water, and the consequent flux diversion is also a possible mechanism for enhanced recovery in low salinity water flooding. It has been suggested that low saline water flooding has a potential for improved oil recovery in all clayey sandstone formation containing crude oil. The result from different work indicates that the initial wetting condition is a crucial property for the effect of low salinity injection. It is obvious that the dominant mechanisms of low-salinity waterflooding are yet to be discovered. However, wettability is considered a key factor that affects fluid distribution in a porous medium. Therefore, the main objective of this paper is to provide theoretical understanding of the effect of brine salinity on rock-wettability alteration for a better understanding of low-salinity-water mechanisms. This paper also contains different effects, parameters and mechanisms which alters wettability of rock towards more water wet condition, which ultimately helps to enhance recovery from sandstone reservoir.

Low salinity water flooding (LSW), Wettability alteration, Electrical double layer expansion, Zeta potential, improved recovery