Treatment of offshore oily produced water: Research and application of a novel fibrous coalescence technique

Rapidly removing oil from emulsified produced water has become one of the most common problems that needs to be urgently resolved as gas-field exploitation enters its later stages, and an effective technique has not yet been established thus far. This paper introduces experimental research and further industrial application of a novel combined fibrous coalescer in the treatment of produced water in an offshore gas-field. Metal and oleophilic polymer fibers were combined at a certain proportion and woven into a fibrous bed with specific structural and geometric properties, which was used as the core separation component of the coalescer. The industrial operation results showed that the oil pollutant concentration of the produced water treated with the novel coalescer was reduced from 1200 to 25 mg/L, well below the 45 mg/L national discharge standard, under a residence time of 180 s and pressure drop of 30 psi. This is the first successful and significant industrial application of the technique in an offshore gas-field, providing a promising alternative for resolving the difficulty of produced water treatment in similar gas-fields, promoting further applications of the technique, and contributing to cleaner production and marine conservation.