Abstract: Suitable pour point depressant (PPD) for improving the rheological property of waxy crude from Alashanko port of Sino-Kazakhstan oil pipeline was screened. The changes in viscosity-temperature curves prior and post to adding PPD, the influence of heating repetitively, high-speed shearing on the viscosity and setting point of crude oil, as well as standing stability were investigated. Results showed that using the grafted copolymer of ethylene vinyl acetate/acrylic acid as PPD with an adding dosage of 50 μg/g and adding at 60 ℃, the setting points of crude oil samples were lowered 10-20 ℃，furthermore, the viscosity, abnormal point and yield value were decreased significantly as well. Heating repetitively below 60 ℃ could cause degradation of the effect of PPD, and the degradation became worse with the lowering of heating temperature. The influence of high-speed shearing on the effect of PPD depended on the shearing temperature, serious negative effect was observed at temperature near the maximum wax precipitation zone. However, the standing stability of crude with PPD was good.

Key words: Alataw Port Crude Oil, Pour-point Depressant, Viscosity-Temperature Curve, yield value