Title: Investigation of the Complex Flow Behavior of Surfactant-Based Fluids in Straight Tubing
Author(s): A. H. Ahmed Kamel, and Subhash N. Shah, Well Construction Technology Center, The University of Oklahoma
Presentation: Canadian International Petroleum Conference/SPE Gas Technology Symposium 2008 Joint Conference (the Petroleum Society’s 59th Annual Technical Meeting), Calgary, Alberta, Canada
Date: June 17-19, 2008
Abstract:
In spite of their wide use in hydraulic fracturing and gravel-pack operations, the complex flow behavior of surfactant-based fluids in straight tubing is least investigated. Accurate prediction of friction-pressure is essential for proper treatment design. Previous correlations from small tubings data and using simple power-law fluid model parameters alone do not scale-up to large tubing sizes for field application.
The properties of one of the most popular surfactants, Aromox APA-T, are thoroughly investigated. It is a highly-active surfactant used as gelling agent in aqueous and brine solutions. Commonly used surfactant concentrations (1.5, 2, 3, and 4% by vol.) are studied. Rheological and viscoelastic measurements are conducted using Bohlin rheometer. Flow tests are conducted using ˝-, 1˝-, 2 3/8-, and 2 7/8-in. tubings.
The results show SB fluid exhibiting a non-Newtonian pseudo-plastic behavior. Fluid concentration and pipe shear have a significant effect on fluid elasticity. The conventional Fanning friction factor versus Reynolds number correlation is improved by including a new dimensionless group that accounts for both fluid elasticity and pipe diameter. A new definition of Deborah number is introduced. Thus, a new correlation for predicting friction factors of SB fluid in straight tubing is developed. The scale-up problem is thus alleviated with the present analysis and it provides more accurate friction-pressure estimates.
