# Using Low Salinity Waterflooding to Improve Oil Recovery in Naturally Fractured Reservoirs
## 5 Conclusions  
1. A new proposed approach of calculating the weighting factor in the mixing area has been presented to improve the simulation accuracy of the low salinity waterflooding. The weighting factor determines the salinity of the brine mixture, hence its properties, as well as it controls the fluid mobility through the calculated relative permeability in the mixing region. The impact of the exponential weighting factor might become significant in the small-scale modelling, which can be useful for modelling and simulation the laboratory coreflood experiments. 2. The results of the coreflood experiments have been integrated into the reservoir simulation to assess the improvement in the oil recovery due to the change in wettability to a more water-wet  
Figure 15: Comparison of the pressure support to the Qamchuqa reservoir during high salinity and low salinity waterflooding, where a similar impact was observed for both flooding schemes on the reservoir subsurface pressure and the produced gas-oil ratio. The natural depletion was provided for comparison. state. The current work highlighted the critical role of the laboratory results that should be performed carefully. Furthermore, the uncertainty in the reported coreflood results has been addressed by computing three levels of change to the relative permeability and simulate each level independently to evaluate their recoveries. 3. The remarkable delay in the water breakthrough can enhance the reservoir productivity and extend the production periods of the producers. However, accurate representation of the relative permeability in the mixing region between the high salinity set to the low salinity set is essential to avoid an overestimation of the sweep efficiency. 4. The relative permeability was successfully used as a proxy to simulate the physical and chemical interaction which have not been modelled explicitly in the simulation model during low salinity waterflooding. The relative permeability emulated the observed change in wettability and the reduction in the residual oil saturation, which enables to simulate the impact of the low salinity waterflooding flawlessly. 5. The study illustrated that there is an opportunity to increase oil recovery from the matrix using low salinity waterflooding even with a minor change in the relative permeability. This sensitive role to the generated relative permeability required accurate experimental results, which are essential for simulating the low salinity waterflooding scenario effectively and avoid any modelling or experimental artefact. 6. The accelerated recovery during low salinity waterflooding encourages a switch from the current conventional waterflooding projects to achieve a higher recovery within a reduced time frame. However, for a full field case, a longer time is required to observe the improvements as the low salinity brine required time to flood the reservoir rock and alter its wettability and reduce the residual oil saturation. Moreover, the fine-scale simulation demonstrated a precise estimation of oil recovery, and it should be used as a reference solution to calibrate the outcomes of the dual-porosity model and avoid any misestimation of the reservoir performance. Conceptualisation, F.A.A. and J.H.L. ; methodology, K.A.E. and K.D.S. ; software, F.A.A. and J.H.L. ; validation, F.A.A., J.H.L., K.A.E. and K.D.S. ; formal analysis, F.A.A. ; investigation, F.A.A. and J.H.L. ; permission acquisition of using field data, F.A.A. ; writing--original draft preparation, F.A.A. ; writing--review and editing F.A.A., K.D.S., J.H.L. and K.A.E. ; visualisation, K.A.E. and K.D.S. ; supervision, J.H.L., K.A.E. and K.D.S. ; APC funding acquisition, J.H.L. All authors have read and agreed to the published version of the manuscript. The APC was funded by Universiti Teknologi PETRONAS, YUTP grant (015 LC0-109). The authors would like to express their deepest gratitude to Universiti Teknologi PETRONAS for providing the required software license and creating the necessary working environment.