Falling oil prices and increased environmental concern lead oil and gas companies to reinject produced water(PW) to reduce both their water management costs and environmental footprint. Membrane processes are an attractive opportunity because they generate a higher quality effluent than conventional PW treatment technologies at a competitive cost.
The objective of the study was to compare the performances of ten membranes to treat PW and identify which of the structural and operational characteristics of the membranes are the success factors to ensure cost-effective, long-term and reliable operation. In oil and gas applications, ceramic filtration media is often preferred owing to its high structural robustness. Nevertheless, polymeric membranes offer the benefits of being less expensive and result in a lower footprint and weight.
Tests using real oilfield PW were run to assess and compare ten membranes according to their oil rejection rate, permeability, resistance to fouling, life expectancy and resistance to ageing.
All membranes tested achieved more than 99% removal of insoluble oil versus 80–85% for conventional technologies. The permeability over time and resistance to fouling were used to identify the most reliable and cost-effective membranes. The robustness of polymeric membranes was confirmed based on good resistance to ageing.