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Chapter 5 Pressure Drop Across Drill Bit

PCB 4223 DRILLING HYDRAULICS SEPTEMBER 2015

BASED ON ASIF ZAMIR

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Learning Outcome:

Understand factors that influence pressure drop across

a nozzle

Understand and able to describe equations involved in

the calculation of pressure drop across a nozzle or

nozzle discharge velocity.

Able to apply equations for calculation of pressure drop

across brill bit or nozzle discharge velocity.

PCB 4223 DRILLING HYDRAULICS SEPTEMBER 2015

BASED ON ASIF ZAMIR

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Reference:

Chapter 4 Applied Drilling Engineering by

Adam T. Bourgoyne Jr.

PCB 4223 DRILLING HYDRAULICS SEPTEMBER 2015

BASED ON ASIF ZAMIR

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Drilling Hydraulics happens in Drilling Circulation System

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An important drilling hydraulics phenomena in the Drill Bit Nozzle:Fluid Pressure Energy is transformed into Kinetic Energy

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+ . + .

= + + + .

Usually neglect for they are relatively small:

Frictional pressure loss

Gravitational

Inlet and out let pressure loss

Simplified energy equation:

= + .

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Let = be the pressure drop across bit nozzle

Nozzle discharge velocity (approximate):

=

.

=

.

Corrected by a discharge coefficient = 0.95 ~0.98:

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The End of Presentation