Model Investigation of Low Salinity Brine Injection on Gas-Condensate Recovery in a Sandstone Reservoir: Effect of Calcium and Sodium Ions

There are many technical challenges associated with the recovery of valuable condensates from gas-condensate reservoirs. While some condensates are immobile far from the production well, others can accumulate close to the producer wellbore area. As a result, such valuable condensates are either not produced or, in some cases, their accumulation might choke the production well, lowering gas productivity. Maintaining reservoir pressure has long been a means of dealing with this problem. This, however, only functions as a temporary solution because the drop-out and immobile condensate production continues unabated. In this study, the effect of injecting brine into a gas-condensate reservoir at various concentrations was examined using a numerical simulation approach. It was found that changing two cations (Ca2+ and Na+ ) concentrations could improve gas-condensate recovery at an injection rate of 490.8 m3 /d (3000 bbl/d). According to this simulation research, the optimised range of sodium ion concentration fell between 0.013 and 0.026 mol/L, with 0.013 mol/L (300 ppm) being the optimum value. Additionally, the low salinity brine injection should have a Ca2+ content greater than 0.0029 mol/L (116 ppm). It was also observed that changes in salinity had a negligible influence on gas recovery. Thus, if recovering lost condensate is of priority, then this recovery strategy is highly recommendable.