Enhancing the Effectiveness of Vertical Water Injection Wells With Inflow Control Devices (ICDs): Design, Simulation and Economics

Water injector completion techniques used traditionally, such as frac packs or openhole standalone screens, were judged to be incapable of meeting all completion objectives and have been reported to loose injectivity over time coupled with the issue of long term injection conformance due to plugging. Another major challenge is to achieve even distribution of the injected water into all zones along the wellbore. Permeability contrasts, formation damage, creation of thief fractures, and changes in wellbore injectivity need to be managed to avoid early breakthrough in adjacent production wells. This study presents the application of inflow control devices (ICDs), fined tuned by reservoir simulations for balancing the water injection profile into various sand formation zones in an open–hole completed injector well in Flo-Z6, a stratified Niger Delta reservoir with communicating layers.The solution targeted at developing a screening tool for deciding candidate layers in Flo-Z6 reservoir and installing special flow control devices, tailor-made for injection wells and with correct nozzle sizes for this particular case.The results from this study show that, the installation of ICDs with different nozzle configuration in the injector wells tailored to equalize the water outflow (for better sweep efficiency), improved the field oil recovery by 11.9% (6.6MMstb). Economic indicators used to validate the profitability of the investment further showed that completing the injectors with different ICD nozzle configuration was more profitable, with an NPV@10% of $192.5million, profit per dollar invested of$6.6, DCF-ROR of 81% and a pay-out period of 1.2 year which is relatively short

Low Salinity Waterflooding; A Promising Prospect to Improve Oil Recovery in the Niger Delta Oil Fields

Low salinity waterflooding is considered one of the most promising and cost–effective methods in oil recovery as a result of wettability change from oil-wet to water-wet. This work considered reducing the residual oil saturation by injection of low salt concentration in order to improve oil recovery. The objective of the study is to reduce the residual oil saturation. In this study, Simulation has been carried out on a synthetic model by using (ECLIPSE 100) as the simulator. Different Salinities of 500ppm,1000ppm, 1500ppm, 2000ppm, 5000ppm, 7000ppm, 10000ppm,30000ppm and 40000ppm were evaluated. Low salinity water was injected at the first year of production and continues to the end of the production life.Effect of salinity on oil recovery was also evaluated. The results obtained showed that low salinity waterflooding improved oil recovery at different salinity as compared to fresh water waterflooding. In conclusion, based on the results of this work, it is possible to choose the best salinity ratio that gives the lowest residual oil saturation