Styrene-maleic anhydride copolymer esters as flow improvers of waxy crude oil

Four comb-like copolymers derived from styrene-maleic anhydride copolymer were prepared and characterized by FTIR, 1H-NMR and elemental analysis. The molecular weight was determined using GPC and their intrinsic viscosity was measured. The prepared polymers were investigated as pour point depressants and flow improvers for waxy crude oil and it was found that, the maximum depression was obtained by the sample that has long branch chain (PPD4) from 27 °C to − 3 °C (ΔPP = 30 °C, at 10,000 ppm), while the minimum depression was exhibited by short branch chain, PPD1 (ΔPP = 21 °C) at the same conditions.The effect of these polymers on the rheology and flow properties of Qarun waxy crude oil was investigated. It was found that the Bingham yield value (τβ) decreased from 6.0 Pa s to 0.5 Pa s for PPD4 at 27 °C and 10,000 ppm. The dynamic viscosity also decreased from 110 mPa s to 24 mPa s for the same sample and the same conditions.