Perpustakaan Digital ITB

Low salinity water injection (LSWI) is a technique that uses injection water whose ion composition has been modified to have a lower salinity compared to the brine in the reservoir, which aims to improve oil displacement efficiency. Success story of LSWI experiments in enhancing oil recovery for the past two decades have led to numerous evolving ideas regarding the combination of LSWI with other Enhanced Oil Recovery (EOR) methods, such as polymer injection. LSWI and polymer injection are two different but potentially complementary EOR techniques. LSWI improves pore-scale displacement efficiency by changing the wettability of the reservoir rocks toward more water-wet. Polymer injection improves fractional flow and sweep efficiency by improving the mobility ratio for the displacement. This study discusses the primary mechanism plus potential benefit of adding polymer substances into LSWI on the suspended well, along with the sensitivity analysis on several key parameters that would affect the simulation result that will be carried out at the structure "B" of the "S" Field in Indonesia. In order to accomplish these main objectives, evaluation of the field characteristic and more literature studies on how low salinity water and polymer injection work jointly together must be taken into account. A simulation study is performed using the CMG GEMTM and CMG STARSTM software with a compositional fluid model. The analysis then is carried out based on oil production and the distribution of oil saturation results obtained. The simulation result proves that there is certainly more increase in cumulative oil production by the end of the project, which has been determined for as long as 15 years, using a combined low salinity water-polymer injection than that uses only high or low salinity water injection. This increase is partly due to the improved oil sweep efficiency, as the addition of polymers can mobilize part of the oil detached by the low-salinity brine, which otherwise would have been trapped. Design of optimized operational parameters results in the best scenario of 13.18% additional gain of oil recovery by injecting the solution with: 1800 ppm of water salinity, polymer concentration of 10 wt%, and 600 bbl/day of injection rate. The combination of LSWI and polymer injection is suggested as a promising recovery method for further research and implementation.