Abstract: The production water treatment system of an offshore oilfield is equipped with 15 units each of Type A and B dual-media filters,which have significant different internal structures. However,the Type B dual-media filters exhibited poor filtration performance.As the volume of water processed continued to increase,the bottleneck issues in the wastewater treatment system became increasingly prominent. To address this problem,there was an urgent need to restore the efficiency of the Type B dual-media filters. By optimizing the air-blowing process and replacing the screen tube structure,the best solution was determined. Seven units of Type B dual-media filters were technically renovated. The implementation effect was remarkable,completely resolving the bottleneck issue of the sewage treatment system and providing an important guarantee for the oilfield's increased reserves and production.

Key words: dual-media filter, production water, water quality, technical renovation