Investigating the synergistic effect between oil soluble surfactants and styrene-maleic anhydride copolymers to enhance the flow properties of waxy crude oil

Styrene-maleic anhydride (SMA) copolymer is prepared and then reacted with octadecyl alcohol SMASA, hexadecylamine SMACA, benzyl alcohol SMABA, and aniline SMAAn to obtain four copolymers. Three oil soluble surfactants are prepared by esterification of mono-, di-, and triethanolamine with oleic acid MEAO, DEAO, and TEAO. The structure of the prepared copolymers is characterized using spectroscopic techniques such as infra-red (FTIR), H-1 nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The prepared copolymers are evaluated individually as flow improvers then mixed with surfactants. From the results, it is found that the copolymer with aliphatic side chain SMACA exhibited the maximum pour point depression (PP = 21 degrees C at 1,500ppm), whereas the rest copolymers SMASA, SMABA, and SMAAn exhibited the same pour point depression PP = 18 degrees C at 1,500ppm. Moreover, the blend (B4) between SMACA and TEAO exhibited the maximum pour point depression PP = 27 degrees C.