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PRODUCED WATER TREATMENT AND DISPOSAL IN OIL WELLS: CASE STUDY OF GIALO FILED 59, EASTERN SIRTE BASIN, LIBYA
Volume (2), Issue (1) , June 2026
Published: 06/30/2026
Abstract: Produced water management has become a critical challenge in mature oil fields due to the increasing water cut and stringent environmental regulations. This study evaluates the treatment and disposal system of produced water in the Gialo Field (Block 59), located in the Eastern Sirte Basin, Libya. The main objective is to assess the efficiency and operational performance of the integrated treatment facilities implemented at Gialo-1 and Gialo-2 stations. The adopted treatment process consists of sequential stages including primary separation in settling and skimming tanks, chemical injection (scale inhibitors, demulsifiers, H₂S scavengers, and oxygen scavengers), and secondary treatment using Induced Gas Flotation (IGF) units. The treated water is subsequently pressurized and reinjected into disposal wells to ensure safe environmental management and reservoir pressure maintenance. Field data indicate that the system handles produced water volumes exceeding 240,000 barrels per day, with oil-in-water concentration reduced from approximately 400 ppm at the inlet to about 150 ppm after primary treatment, followed by further polishing in IGF units to meet reinjection specifications. The integration of a Vapor Recovery Unit (VRU) and emergency handling systems enhances environmental protection and operational reliability. The results demonstrate that the implemented system provides an effective and technically reliable solution for large-scale produced water management. However, continuous monitoring, optimization of chemical dosing, and process control are essential to maintain performance under variable field conditions. This study highlights the applicability of integrated treatment systems as a practical model for managing produced water in similar mature oil fields.
Keywords: Oil, water, crude oil-water separator, water treatment.
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