Serbian oil company NIS has received environmental clearance to start testing an enhanced oil recovery (EOR) method at the Velebit production field. The approval covers the environmental impact assessment prepared for the project, for which NIS issued a tender in August.
The pilot project involves constructing a system to assess the performance of injecting a surfactant–polymer (SP) mixture into three newly drilled injection wells, with the goal of increasing production from seven nearby wells. The SP method is an advanced EOR technique widely used in mature oil fields to mobilize crude that conventional water flooding cannot recover.
The technology works by using surfactants to reduce the interfacial tension between oil and water, allowing previously trapped oil to flow more easily through rock formations. Polymers are added to increase the viscosity of the injected fluid, improving the sweep efficiency of the reservoir and reducing premature water breakthrough. Together, these components are designed to boost the volume of oil that can be extracted from aging deposits.
According to the documentation NIS submitted in April, the Velebit field currently produces around 592 tons of oil per day, with a water cut of 85%, and about 15,500 cubic meters of dissolved gas per day.
The project includes installing SP-mixing equipment, water preparation and filtration units, surfactant storage tanks, loading platforms, and a network of pipelines connecting the central system to the injection wells. Development will be carried out in two phases. The first phase, expected to be completed by December 2026, focuses on determining optimal injection parameters. The second phase, scheduled to run through 2041, aims to increase the recovery rate by 7.5% and raise overall oil output.
The Velebit field in the municipality of Kanjiza is Serbia’s largest oil deposit. Discovered in 1968 and in operation since 1985, the field has been approaching depletion after years of intensified extraction following the privatization of NIS.
