Low Salinity Water Injection Modeling by Craig-Geffen-Morse (CGM) Method: A Case Study in a Homogeneous Reservoir

Abstract Low Salinity Water Injection (LSWI) is widely used in the global oil industry for enhanced oil recovery (EOR) due to its operational simplicity, cost benefits, and environmental friendliness compared to other methods. However, the underlying mechanisms of LSWI are still debated, prompting the need for a more realistic model to simulate fluid displacement in reservoirs. This study proposes the Craig-Geffen-Morse (CGM) method as an alternative approach to model low salinity waterflooding and reservoir fluid displacement. The study also investigates the impact of reservoir properties on oil recovery during low salinity water injection, considering factors such as pattern area, reservoir thickness, sand layer permeability, and fluid mobility ratio. Using Visual Basic for Applications (VBA) codes in Microsoft Excel, the CGM method is implemented to calculate equations and correlations. The study conducts a sensitivity analysis to observe the effects of several parameters on reservoir performance. The results show that injecting fresh water may increase oil recovery by 8.2% compared to high salinity water injection. While water salinity data is not directly considered, the study demonstrates a clear relationship between reduced water salinity and improved oil recovery based on certain reservoir property conditions. Additionally, variations in pattern area and thickness have minimal impact on reservoir performance, yielding similar oil recovery factors. Sand layer permeability only affects oil recovery when high salinity water is used, and higher fluid mobility ratios significantly reduce oil production. The findings align with previous research, supporting the applicability and practicality of the Craig-Geffen-Morse method for modeling low salinity water injection. These findings contribute to further development in this field.