Comparison of Available Water Resources in terms of Formation of Mineral Deposition for Injection into a Petroleum Reservoir

Recently, water injection has been widely studied as one of the most popular enhanced/improved oil recovery methods. Most of the studies focus on low salinity and seawater injection, emphasizing the quality of the injection fluid. In addition, receiving the required quantity of injection water and high-quality injection fluid is crucial. Produced water with oil and urban wastewater can be regarded as appropriate resources for water injection projects to mitigate the environmental concerns and the cost of water treatment. This study examines several water resources suggested for injection into an oil reservoir near the Persian Gulf to find the optimal choice. The studied resources are low-salinity water, seawater (from the Persian Gulf), produced water, and urban wastewater. Injection fluid quality, compatibility with formation brine, scale formation, and usability were the primary factors considered when selecting the optimal water resource. Accordingly, geo-chemical software OLI Scale Chem was used for compatibility check and estimation of scale type and amount. As a result, the least amount of scale formed after urban wastewater injection, whereas seawater was the most incompatible water source. It should be emphasized that various non-technical factors, such as the climate of the region, the water transmission route and associated costs, economic conditions of the country, environmental concerns, and the priority of wastewater usage may significantly impact resource selection.