The Variation of the Gel Point of Daqing Crude Oil with Pipelining History

Abstract

Daqing crude oil is a typical waxy crude oil with a wax content of 26.6 wt% and a gel point of 32°C. In order to conduct the safety analysis of pipeline operation, the variation of gel point of Daqing crude oil with thermal and shear history was studied through pipelining simulation experiments. The experiments were performed under different annual throughputs and shear rates of pipeline flow. The results suggest that the change of shear action has little effect on the gel point of crude oil. As the final dynamic cooling temperature is increased, the change of gel point experiences two stages, staying constant at first and then decreasing. Through 13 groups of pipelining simulation experiments, the effects of heating temperature ranging from 45°C to 65°C on gel point of Daqing crude oil were studied. It has been indicated that the gel point increases as the heating temperature is increased under the same final dynamic cooling temperature. The relation equation was constructed to be used to predict the gel point under certain heating temperatures and final dynamic cooling temperature. The average absolute deviation of 52 predicted values of gel point is 0.58°C.