Core-Annular Flow of Heavy Oil and Herschel-Bulkley Fluids in Straight and Slowly-Varying Tubes
The recovery and transportation of heavy and highly viscous oils involves energy consuming flow processes, from the reservoir, through the production wells, to the pretreatment station and the pipelines. Drag reduction in heavy oil transportation can be obtained by partially up-grading, oil-water emulsification, dilution with light oils and condensates and core-annular flow. Drag reduction using core annular flow consists in co-injecting crude oil and a low viscosity fluid such that the oil forms a core and the low viscosity fluid forms an annulus. Conventionally, Newtonian fluids, such as water, have been used extensively as the drag- reducing fluids. In this paper, we investigate the potential of drag reduction using a Herschel-Bulkley fluid, i. e. a fluid characterized by a yield stress and, above the yield stress, by a shear-thinning character. The yield character makes such fluids suitable for core- annular flow with a self-centralized heavy oil core. We examine theoretically the perfect core-annular flow in straight and slowly varying-diameter tubes. The influence of the main parameters (viscosity ratio, power law exponent, etc.) is discussed based on calculations for realistic cases.
P. L. J. ZITHA
Delft University of Technology, The Netherlands
国际会议
首届世界重油大会(The Technical Sessions of the First World Heavy Oil Conference)
北京
英文
707-712
2006-11-12（万方平台首次上网日期，不代表论文的发表时间）