Oil Recovery Mechanism(s) by Low Salinity Brines and Their Interaction with Chalk

Research demonstrates that low salinity brines (LSW) can significantly enhance oil recovery from chalk reservoirs, with the most effective dilution ratio found to be 1:10 seawater (SSW). The study, conducted using Stevns Klint chalk outcrops from Denmark, revealed that higher calcium ion concentrations in effluent and increased pH—particularly at pH 8—correlate with improved oil recovery. Dissolution and ion exchange processes, including the deficiency of magnesium ions, were identified as key mechanisms contributing to these effects. These processes may also impact chalk integrity, potentially leading to fine migration and reduced flow resistance, which further enhances oil displacement efficiency.

Hamouda, A. A., & Maevskiy, E. (2014). Oil Recovery Mechanism(s) by Low Salinity Brines and Their Interaction with Chalk. Energy & Fuels, 28(11), 6860–6868. https://doi.org/10.1021/ef501688u