Summary
Brine viscosities are an important property in sand-control and coil-tubing
operations. Viscosities are used to calculate sand settling rates for
gravel- packing and frictional pressure losses. Because of limited
brine-viscosity data, viscosites were determined for conventional completion
fluids using an Oswald viscometer. Then, 3D equations were determined as a
function of density and temperature for calcium chloride; calcium bromide;
calcium chloride and calcium bromide; calcium bromide and zinc bromide;
three-salt mixture of calcium chloride, calcium bromide, and zinc bromide; and
sodium bromide solutions. All equations had an absolute average deviation
from the measured values of less than 10%.
Introduction
Brine viscosities are an important property required for many fluid-dynamic
situations. When displacing the drilling fluid to brine, the brine
viscosity is needed to determine pump horsepower requirement. Once the well is
filled with completion fluid and perforated, Darcy’s law, which requires the
viscosity, can be used to estimate brine losses to the formation in an
overbalanced situation. During gravel-pack operations, the viscosity is
needed in Forchheimer’s equation to predict sand height (Penberthy and
Shaughnessy 1992). The brine viscosity is also needed to predict flowing-well
surface temperatures and is used for other predictive correlations (Vollmer et
al. 2004; Beall et al. 2004).
Viscosities for water and low-density brines are readily available, even at
elevated pressures (Kestin et al. 1977; Ershaghi et al. 1983). However,
very little work has been done on brines greater than 10.0 ppg. One source
provided brine viscosities in chart form at densities up to 16.5 ppg and at
temperatures ranging from 40 to 500°F (Foxenberg 1996). However,
interpolating within these brine densities is difficult, but these were the
best data the industry had available. Because these viscosities were
established using an Oswald capillary viscometer, measuring these brine
viscosities above 250°F is impossible because of the boiling of these
brines. Obviously, the brine viscosities above the boiling point were
extrapolated from the measured data. Because no experimental data were
provided, the accuracy of these brine viscosities is questionable, and brine
viscosities above 16.5 ppg are needed.
The purpose of this work is to provide brine viscosities in equation form
and to report the accuracy of these equations from the experimental data.
© 2006. Society of Petroleum Engineers
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History
- Original manuscript received:
10 May 2004
- Revised manuscript received:
29 November 2005
- Manuscript approved:
8 February 2006
- Version of record:
20 June 2006
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