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

Author(s)

Rodriguez, O. M. H. ^[1] ; Bannwart, A. C. ^[2] ; de Carvalho, C. H. M.

Affiliation

^[1] USP, SEM EESC, Engn Sch Sao Carlos, Dept Mech Engn, BR-13566970 Sao Carlos, SP - Brazil

^[2] Univ Estadual Campinas, Fac Mech Engn, Dept Petr Engn, Campinas - Brazil

• Document type: Journal article
• Source: JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING; v. 65, n. 1-2, p. 67-75, MAR 2009.
• Web of Science Citations: 35

Abstract

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 degrees 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 degrees 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. (c) 2009 Elsevier B.V. All rights reserved. (AU)