Experimental Simulation of the Effect of Shear on Rheological Properties of Beneficiated Waxy Crude Oils: Theoretical Basis and Application

摘要

Flow properties such as viscosity and gel point of waxy crude oils, particularly the beneficiated waxy crude oils, are sensitive to shear history that the crude oil experienced, called the shear history effect. To understand quantitatively this shear history effect are necessary to oil pipeline design and operation. For experimental simulation of the shear process during pipelining, shear rates of turbulent pipe flow, and flow through centrifugal pumps and throttle valves are necessary. Stirred vessels are usually used for shear simulation in laboratory, therefore shear rate in the stirred vessels has to be known before shear simulation. Based on relationship between energy dissipation rate and the shear rate, approaches are developed and presented for calculation of shear rates in the above-mentioned specific flows. Combined with the entropy generation due to viscous flow in the shear process, which has been proved to be a proper parameter for simulation of the shear history effect, the shear history effect on viscosity and gel point of the beneficiated waxy crude oils has been experimentally simulated accurately.