Qualitative Analysis Of Dynamic Effects In Oil Pipelines
Free (open access)
D. Guaycochea-Guglielmi & G. Soto-Cortés
Pipelines are used in Mexico to transport different types of crude oil from the production areas to refineries and harbours. Pipeline systems have diameters of 20, 24, 30 or 36 inches and variable length, reaching several hundreds of kilometres in some cases. The distance between pumping stations is variable (from 10 to almost 200 km), depending mainly on topography. In some cases it is necessary to raise the fluid to the central plateau (more than 2,200 m above sea level); sectors of the conduits have to go across very rough terrains and need many changes of directions, particularly vertical. High discharge pressures are necessary in some pumping stations and pressure reduction valves are used in selected sections. As a result, in certain sectors of the pipeline system, head losses cannot be predicted with reasonable accuracy by conventional formulas, even considering corrections due to pipe aging or inlay deposits. An analysis, based on field measurements and supported on experimental and numerical concepts, shows that the friction factor is significantly influenced by dynamic effects, originated mainly in the curvature of the lines, which affects the velocity profile. The purpose of this paper is to show and describe these results, comparing different pipeline sectors with distinctive characteristics. The friction factor calculated with conventional equations (Swamee Jain) is compared with the one obtained from the Darcy Weisbach formula. An attempt is made to correlate the pipeline curvature with the friction factor in terms of a qualitative analysis. Further research should lead to the definition of adimensional parameters to be included in new algorithms, as was already proposed in other cases, particularly for aqueducts. Keywords: oil pipelines, head losses, dynamic effects.
oil pipelines, head losses, dynamic effects.