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

Abstract

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 (τB) was decreased from 1.63 Pa at 32°C to 0.3 Pa at the same temperature and 500 ppm concentration of [ODMBA].