The Study Of Structure-activity Relationship Of Oilfield Chemicals And Demulsifier

When oilfield chemicals enhance oil recovery,decrease oil sediment concentration and promote oil liquidity,they also affect demulsification and dehydration of heavy oil.The fluorescence spectroscopy,interfacial tension,interfacial dilational rheology and atomic force microscope were used to investigate the micellization behavior of oil and water,the interfacial properties and aggregation behavior of all kinds of oilfield chemicals in the absence or presence of demulsification SD-1.The effect of oilfield chemicals on the crude emulsion breaking has also been studied from the perspective of oil-water interfacial film.By comparing the simulation of aviation kerosene oil system,oil system and asphaltene system,this article explores the mechanism of influence that various oilfield chemical agents used in the process of heavy oil recovery,have on demulsification effect of heavy oil produced liquid in Binnan part of Shengli Oilfield,thus providing basis for the development and rational utilization of oilfield chemical agents.First,SD-1,the most effective demulsifier is selected out as a research object,from five commonly-used demulsifiers in Shengli Oilfield.Viscosity reducer OP-10 and frother QP-1 help SD-1 demulsification and dehydration,but viscosity reducer AES,frother APG and clay stabilizers(NT-1,NT-2)do not.Second,the influence of three types of oilfield chemical agent on the demulsification of Binnan heavy oil was investigated by steady-state fluorescence,interfacial tension,rheological property and atomic-force microscope.The results show that,by the respective effects of electrostatic repulsion and steric hindrance,OP-10 and QP-1 increased I1/I3 value of emulsion breaking system,loosen the micelle structure and surfactant molecule permutation at oil-water interface,and can inhibit the aggregation of asphaltene molecules on the interface.The asphaltene molecules changed from the zonal distribution into a punctuate distribution,which weaken the intensity of interfacial film,reduced the dilational modulus,and increased dehydration rate.By the strong hydrophobic effects,AES,QP-1,NT-1 and NT-2,with demulsifier molecule,formed mixed micelles where molecules gather closer,the intensity of interfacial film strengthen,dilational modulus increased and dehydration rate decreased.The four oilfield chemicals(AES,APG,NT-1,NT-2)promoted the formation of cross-linked aggregates of asphaltene molecules by electrostatic and hydrophobic interactions,and lead to the molecules aligned closer.The intensity of asphaltene interfacial film enhanced and the dilational modulus increased.Due to its electrostatic interaction,I1/I3 value of demulsification system containing cationic NT-2 was greater than that of anionic NT-2.In contrast to demulsification system containing NT-2,the system containing NT-1 formed micelles which structure and molecule permutation at the interface were more looser,the intensity of interfacial film were weaker,dilational modulus decreased.The stability of emulsion was closely related to the interfacial tension and dilational modulus,the emulsion was more stable with the increase of both of them.