STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

830 Drilling and Well Completions
Bingham plastic fluid
z = 2, ...(-E)"
(4-86)
Power law fluid
z = IC(-$)"
(4-87)
Herschel and Buckley fluid
z = 2, +I+$)"
(4-88)
where T = shear stress
v = the velocity of flow
dv/dr = shear rate (velocity gradient in the direction perpendicular to the
flow direction)
p = dynamic viscosity
zy = yield point stress
kp = plastic viscosity
K = consistency index
n = flow behavior index
The k, zY, pp, K and n are usually determined with the Fann rotational
viscosimeter. The Herschel and Buckley model is not considered in this manual.
Flow Regimes
The flow regime, Le., whether laminar or turbulent, can be determined using
the concept of the Reynolds number. The Reynolds number, Re, is calculated
in consistent units from
Re = - dvp
P
(4-89)
where d = diameter of the fluid conduit
v = velocity of the fluid
p = density of fluid
p = viscosity
In oilfield engineering units
Re = 928- d,vV
P