BAKER HUGHES - Drilling Fluids Reference Manual

PRESSURE PREDICTION AND CONTROL
fluid is pumped into the well. See Figure 12-9. This is further explained in the Wait and
Weight Method of well control.
Equivalent Circulating Density
Figure 12 - 9 Kill Fluid Weight
It has been mentioned previously, that when the mud pump is running, the bottom-hole
pressure is increased by the annulus friction loss. When the fluid is moving up the hole, the
friction of the fluid against the drillpipe, the wellbore sides, and the fluid viscosity all combine
to create a friction pressure that resists flow. The annular pressure loss is that part of the pump
pressure that it takes to pump the fluid in the annulus. This pressure value reacts against the
bottom of the hole and increases bottom-hole pressure. The actual fluid weight, plus the
increase in bottom-hole pressure due to the annulus friction loss, can be expressed as an
equivalent fluid weight and is referred to as Equivalent Circulating Density (ECD).
ECD,
lb
m
/ gal = Fluid Weight +
Annular frictionloss
TVD × 0.052
( psi)
ADVANTAGE engineering software contains a field proven ECD simulator. This simulator
can be run in the HPHT mode where it uses Fann 70 / 75 data for downhole rheological
properties and retort and PVT data to calculate downhole densities. This results in an extremely
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 12-24