Page 432 - Air and Gas Drilling Manual

9-36 Air and Gas Drilling Manual
conditions in the cased annulus section along H 1. This is accomplished by
determining the Reynolds number at the exit end of this annulus section and
assuming this Reynolds number approximates the flow conditions throughout the
annulus section.
Using Equation 4-11, the approximate specific weight of the gas as it exits this
cased annulus section and starts into the Tee is determined from P Tee. This is
9 114 3 1 0)
(, . ) ( .
ga1
.
.
( 53 36) ( 504 41)
0 339 lb/ft 3
.
ga1
Using Equation 1-2, the density of the gas as it exits this annulus section, ga1 , is
0 339
.
ga1
32 2
.
lb sec 2
0 0110
.
ga1 4
ft
From Equation 9-7, the kinematic viscosity of the gas at this location, ga1 , is
0 000000251
.
ga1
.
0 0110
ft 2
.
0 0000238
ga1
sec
The kinematic viscosity of the aerated drilling fluid mixture can be
approximated with an average kinematic viscosity term. This average kinematic
viscosity term can be defined by weight averaging the separate viscosities with the
weight rates of flow of the separate fluids. Therefore, the kinematic viscosity term
can be modified to determine the average kinematic viscosity, , of the mixture
ava1
as it exits this annulus section. This is
w ˙ g ga1 w ˙ m m
ava1
w ˙ g w ˙ m
The average kinematic viscosity of the mixture as it exits this annulus section,
, is
ava1