Synergistic effect between surfactants and polyacrylates-maleicanhydride copolymers to improve the flow properties of waxy crude oil

Four copolymers were prepared by copolymerization of octadecyl acrylate with maleic anhydride abbreviated as ODM], the resulted copolymer was reacted with octadecylalcohol ODMSA], hexadecylamine ODMCA], benzyl alcohol ODMBA] and aniline ODMAn]. Three oil-soluble surfactants were also prepared by esterification of mono, di and tri ethanolamine with oleic acid, abbreviated as MEAO, DEAO and TEAO]. These compounds were purified and characterized by FTIR, ¹H-NMR and GPC. The prepared copolymers were evaluated individually and mixed with the oil-soluble surfactants and evaluated as flow improvers and pour point depressants for waxy crude oil. It was found that, the polymer with aromatic side chain ODMBA] exhibited the maximum pour point depression ΔPP?=?24°C at concentration 1000?ppm, while the minimum pour point depression was obtained by ODMCA] which pronounced ΔPP?=?15°C at 1000?ppm. Furthermore, the blend B4] between ODMBA] and oil-soluble surfactant TEAO] achieved extra depression of pour point (ΔPP?=?30°C). The rheological properties of the treated and untreated crude oil with the polymeric additives were also investigated and it was found that Bingham yield value (τ_B) was decreased from 1.63?Pa at 32°C to 0.3?Pa at the same temperature and 500?ppm concentration of ODMBA].