Study and application on high effective treatment technology of operation wastewater in oilfield

In oilfields, there are many kinds of operation wastewater from different places, with complex components, which are commonly collected, mixed and stored in a special station, and treated exclusively and then injected into the formation. The pollutant content of mixed operation wastewater is high, the emulsification degree of it is high, and the flocculation sedimentation of it is difficult. The effect of commonly used "flocculation-sedimentation-filtration" process of water injection treatment is very poor, then resulting in the main index of water injection "suspended matter content" seriously exceeding the standard. It can not be re-injected, even if mixed with ordinary sewage then come into the conventional water injection treatment station, will also have a serious impact on the system. In this study, a new type of solid-phase catalytic air oxidation technology is used to treat the wastewater with aeration oxidation processing at first, then the flocculation properties are improved combining with an enhanced gel breaking coagulant. Then an usual cationic polyacrylamide flocculant is added for flocculation prior to following sedimentation. After treatment mentioned above, the removal rates of oil and suspended matter reached 94.1% and 97.9% respectively, and the water quality is up to oilfield injected water quality standard. This technology has the advantages of simple process and low cost, and is suitable for application in most oil fields.