Sustainable Water Sourcing and Treatment Methods for Water Injection Projects Using Shallow Aquifer

Abstract

Abstract Reservoir supporting by water injection is a mandatory aspect in aged depleted fields; however, securing a sustainable water source with low treatment expenditures is still a challenge for the operating companies. Gulf of Suez Petroleum Company (GUPCO) firstly had implemented water injection by seawater in the study oil-producing field. Then field requirements and conditions changed: which led to utilizing a shallow water aquifer in supporting the depleted reservoir blocks. GUPCO has been producing this aquifer water for 26 years securing the field water injection needs, till the field cumulative production has already surpassed one Billion Barrel Oil. Before field implementation, several compatibility tests, field studies, and scale tendency calculations had been performed to confirm the benefit of using the aquifer water over GoS (Gulf of Suez) seawater. The Aquifer formation water has less tendency to form sulfate hard scales due to its low content of sulfate ions compared with seawater. De-sulfonation of injection water was omitted due to its higher Capex and Opex expenditures. The application of seawater injection had been already implemented and it dedicated higher costs to meet the required injection criteria. Therefore, the aquifer water was extracted via offshore production wells. These offshore Water Source Wells (WSWs) were completed with Electric Submersible Pumps (ESPs); additionally, screens with gravel pack completions were implemented for sand control. Studies figured out that produced water may not receive any surface treatment or filtration and it can be directly distributed to injector wells. However, the aquifer water contains high concentrations of dissolved carbon dioxide; therefore, the deposition of carbonate scales was predicted in the study phase and confirmed in the operation phase. The great advantage of the ground water aquifer is that there is no need to lay down a subsea pipeline from any onshore facility and all the pipelines between offshore platforms are short with an affordable cost. Generally, this aquifer water can be generalized and used as a good alternative of seawater for water injection projects in Gulf of Suez area. This paper will address the successful application of GUPCO for this unique water injection system and the encountered challenges and drawbacks to achieve maximum field efficiency. The paper will also compare the actual case studies and field applications of implementing seawater and aquifer water in water injection fields. The comparison will include reservoir souring, scale deposition, operational efficiency, and implementation challenges.