Composite Demulsifier for Oil Treatment at a Late Stage of Field Operation

Currently, most oil fields in the Russian Federation are at a late stage of operation. The oil in such fields is mainly highly viscous, and water cut of many oil wells is up to 90 %. Heavy high-viscosity water-oil emulsions are formed during production. The presence of water and salts in crude oil deteriorates its quality, reduces the service life of oil production and refining equipment, complicates oil transportation and processing. The development of methods for produced oil properties improving is an important task in oil production and refining. One of the modern methods to solve this problem is the development and use of complex action chemicals (CAC). These chemicals, when used, exhibit both demulsifying properties and properties of asphalt-resin-paraffin deposits (ARPD) inhibitors. This approach allows to improve the quality of oil, simplify and, consequently, reduce the cost of oil production, transportation and refining. Also, in the context of economic and political instability in the world, import substitution – the use of domestically produced components – is becoming increasingly relevant in the development of CAC.The purpose of this work was to develop a demulsifier for breaking heavy water-oil emulsions, which also exhibits the properties of an ARPD inhibitor, and to evaluate the efficiency of using this demulsifier in the oil fields of the Russian Federation.A block copolymer of ethylene oxide and propylene oxide (Laprol 6003-2B-18) was used as a nonionic surfactant in the composition. To improve the properties of the main substance, the auxiliary substances were used: an active base of DeKemix demulsifiers (manufactured by JSC «OZNH») and a salt of alkyl benzene sulfonic acid (ABSA). The demulsifying efficiency of the composite demulsifier was evaluated based on water-oil emulsion with 50 % water cut.The amount of residual water in the water-oil emulsion was determined according to State Standard 2477-2014. The structural fragments of the initial Laprol and the composite demulsifier were studied by IR spectroscopy in the range of 4000–650 cm-1.In the course of this work, several demulsifiers were obtained, exclusively composed of domestically produced components. Their physical and chemical properties were determined, demulsifying ability was assessed, and parameters to determine compliance with the basic requirements of potential customers were identified.