文档介绍：PRESSURE LOSSES
The pressure losses within a well
are reflect ed i n th e st and pi pe
pressure
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Pressure Losses
Pressure losses
are the sum of all
pressure losses in
the system
Ps = Psurf + Pdp + Pdc + Pbit + Pdpa + Pdca
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Pressure Losses
The majjyority of the pressure
losses in the circulating system
are in turbulent flow
Surface connections, drill pipe,
drill coll ars and bit
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Pressure Losses
The velocity
vectors are not
ordered and the
velocity profile is
very flat with the
average velocity
approximately
equal to the
maximum velocity
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Pressure Losses
This is the classic
Fanning Friction
Factor Diagram
The friction factor
is a function of the
roughness of the
pppipe and the
Reynold’s number
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Pressure Losses
The Reynold’s number can be
determined from the following
equation
Dvρ
R = m
e μ
In turbulent flow the viscosity is
PV
μ=
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Pressure Losses
e/es from the
Moody Diagram Riveted Steel
¾1. Cast Iron
Concrete
1
¾2. Galvanized Iron e=
2
¾3. Asphalted Cast 3
4 e=
Iron e/D
¾4. Commercial e=
Steel or Wrought Iron
e=
e=
¾5. Drawn Tubing e=
e=
5
e=
e=
110100
Pipe diameter, inches
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Pressure Losses
The frictional pressure loss is
related to the friction factor by
the following equation
ρ v 2lf
P = m
(104 )D
e/D is if you assume 4” ID
steel and the friction factor
would be
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Pressure Losses
f =