Mechanisms behind low salinity water injection in carbonate reservoirs

• History matching of recently published corefloods for low salinity water injection.
• Investigating the best way of history matching low salinity water injection effect on oil recovery.
• Highlighting important parameters that should be considered in modeling low salinity water injection effect in carbonates.
• Wettability alteration is still believed to be the main mechanism underlying the incremental oil recovery by LSWI.
• Oil endpoint relative permeability is more sensitive to the LSWI effect than is water endpoint relative permeability.

The low salinity water injection method (LSWI) has become one of the important research topics in the oil industry because of its enormous possible advantages. The objective of this paper is to investigate the mechanism behind the LSWI effect on oil recovery through data matching. The UTCHEM simulator was used to match the cycles of the injected seawater and different dilutions of the latter for two recently published coreflooding experiments. The result from the history matching revealed that the wettability alteration mechanism is believed to be the main contributor to LSWI. Based on this finding, an analytical model for oil recovery predictions can be developed.