采出水处理回用高通量膜法技术

Treatment and reinjection technique of oilfield produced water with high-flux membrane

针对某低渗透油田企业采出水,开展了现场膜处理小试实验,考察了采用膨化聚四氟乙烯(ePTFE)微滤膜工艺处理采出水达到回注标准的技术可行性,确定了膜前过滤介质及其最佳浓度,并就实际应用进行了工艺设计。采用膜前过滤介质,避免了采出水中的石油类物质对膜产生污堵等负面影响。膜前过滤介质为吸附性介质硅藻土与刚性颗粒介质碳酸钙复配,最佳复配质量浓度为二者各30 mg/L。在采用膜前过滤介质的最佳工艺条件下,膜通量可达6430 L/(m2·h),为企业目标通量的20余倍,且膜通量衰减显著延缓。采出水经过滤处理后,出水水质稳定达到《碎屑岩油藏注水水质指标及分析方法》(SY/T 5329—2012)中的回注1级标准。

A pilot experiment of on-site membrane treatment was launched for the oilfield produced water of one low-permeability oilfield enterprise.The technical feasibility of using the expanded polytetrafluoroethylene(ePTFE)microfiltration membrane process to treat the produced water to reach the reinjection standard was studied.The filter medium before membrane and its best concentration were investigated,and the process design for practical application was developed.The application of filter medium before membrane can avoid the negative effect such as fouling on the membrane brought by the petroleum substances in oilfield produced water.The filter medium before membrane is compounded by absorbent medium diatomaceous earth and rigid granular medium calcium carbonate,and their best concentrations are both 30 mg/L.Under the optimal conditions with filter medium before membrane,the limit flux can reach 6430 L/(m2·h)with low attenuation,and it is 20 times that of the target for industrial application.After filtered,the quality of the produced water is stable and reaches the reinjection level 1 standard in the“Water Quality Standard and Analysis Method of Oilfield Injecting Waters in Clastic Reservoirs”(SY/T 5329-2012).