Pressure loss in core-annular flow: Modeling, experimental investigation and full-scale experiments

• Published in: Journal of petroleum science & engineering Vol. 65; no. 1; pp. 67 - 75
• Main Authors: Rodriguez, O.M.H., Bannwart, A.C., de Carvalho, C.H.M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.03.2009; Elsevier
• Subjects: Applied sciences; core-annular flow; Crude oil, natural gas and petroleum products; Energy; Exact sciences and technology; experimental investigation; Fuels; heavy oil; Oil–water flow; pressure loss; reduction factors; two-phase flow; South America; Brazil; America; Oil–water flow; experimental investigation; reduction factors; heavy oil; core-annular flow; pressure loss; two-phase flow; Correlation; Tube; Deep water; Water flow; Oil-water flow; Modeling; Pressure; Pipeline; Production rate; Crude oil; Pressure measurement; Produced water; Pressure loss; Heavy oil
• ISSN: 0920-4105; 1873-4715
• DOI: 10.1016/j.petrol.2008.12.026

The use of core-annular flow pattern, where a thin fluid surrounds a very viscous one, has been suggested as an attractive artificial lifting method for heavy oils in the current Brazilian ultra-deep water production scenario. This paper proposes a more refined pressure-loss prediction model for core-annular flow which includes a slip ratio term that implicitly accounts for the buoyancy of the oil core. Frictional pressure-gradient measurements in upward-vertical and horizontal core-annular flows in a 28.4-mm-i.d. 2.5-m-length glass tube (tap water and crude oil of 500 mPa s and 925 kg/m 3 at 20 °C) and 77-mm-i.d. 274-m-length steel pipeline conveying an ultra-viscous crude oil (36,950 mPa s and 972.1 kg/m 3 at 20 °C), respectively, are reported. The model shows very good agreement with the present data and data from the literature, improving some correlations previously developed. Regarding the onshore-field experiments, two pressure-gradient reduction factors are proposed. The observed improvement of oil production rates and pressure-loss reductions are remarkable.