Chemical Treatment Scenario of Produced Fluid by ASP Flooding Using NaOH, Alkylbenze Sulfonate and HPAM at Daqing Fields

ASP flooding using NaOH, alkylbenze sulfonate and HPAM has been put into industrial application at Daqing Fields. While significantly increasing oil recovery, it has also brought in new challenges for the handling of produced fluid such as precipitation of new mineral particles in the aqueous phase, scale deposition, foam, stable reverse emulsion in both produced fluid and produced water, and expanded rag layers in electrostatic treaters. To facilitate handling of the produced fluid and produced water by ASP flooding, numerous chemicals have been developed and applied, such as antifoams, demulsifiers, dual functional demulsifiers and reverse demulsifiers, sulfide scavengers, chelatants, and alkalines. A comprehensive scenario for the application of the above mentioned chemicals has been developed and applied in the handling of ASP flooding produced fluid at Daqing Fields. The scenario consists of continuous injection of dual functional demulsifier and reverse demulsifiers, antifoams at the inlet of production separators or into the produced water heated, recycled back to wellsites and blended into wellhead produced fluid to facilitate its flow to oil gathering stations, continuous injection of chelatant and alkaline into the produced water recycled back to be the wellheads, temporary injection of demulsifier and alkaline into the feed of bath heaters upstream of electrostatic treaters on an as-needed basis, batch injection of sulfide scavenger into the produced water recycled back to the wellheads, as well as batch injection of sulfide scavenger and alkaline into the feed or backwashing water of media filters treating produced water. The chemical treatment scenario has been successfully applied in 4 ASP projects using NaOH, alkylbenze sulfonate and HPAM at Daqing fields, significantly improving the performances of surface production facilities handling ASP flooding produced fluid.