Pilot study on hydrophilized PVDF membrane treating produced water from polymer flooding for reuse

To meet the oilfield reinjection water quality for low and ultra-low permeability reservoirs in China, a hydrophilized polyvinylidene fluoride (PVDF) membrane (approximate 110 m2) manufactured by our laboratory was used for treating produced water from polymer flooding for reuse in Daqing Oilfield. The results showed that a temperature of 37 °C, volume reduction factor (VRF) of 4, transmembrane pressure (TMP) of 0.20 MPa and crossflow velocity of 4.5 m/s were the feasible operation conditions for the membrane, and the average flux could reach 75 L/(m2 h) (LMH). In the permeate, the total suspended solids (TSS) was consistently below detection limits (2.5 mg/L) and the medium grain size was undetectable. The content of hydrolyzed polyacrylamide (HPAM), crude oil and turbidity were respectively lower than 50 mg/L, 1 mg/L and 1 NTU, respectively. The parameters of treated water all met the highest oilfield reinjection water quality in China and the results demonstrated the hydrophilized PVDF membrane had good anti-fouling characteristics in treating produced water from polymer flooding for reuse.