©2015Weatherford.Allrightsreserved.
nConstantBottomholePressure(CBHP)–PressurizedMudCapDrilling
(PMCD)forThangLongJOCWellHSD-BM-6P
nBaoTaQuoc
nMPDProjectEngineer
ManagedpressureDrilling
©2015Weatherford.Allrightsreserved.
©2015Weatherford.Allrightsreserved
ManagedpressureDrilling
IntroductiontoMPD
ConventionalDrilling:
BHP=MW+ECD
Onlyadjustmentsavailablewith
mudintheholearepumpson,
pumpsoff,andpumpspeed.
ManagedPressureDrilling(MPD):
BHP=MW+ECD+
Backpressure
EffectiveBHPcanbechanged
significantlyandquicklywith
fewerinterruptionsindrilling
ahead.
©2015Weatherford.Allrightsreserved.
©2015Weatherford.Allrightsreserved
ManagedpressureDrilling
MPDVSUBD
•MPDrequiresaccuratepressurecontrol
toavoidinfluxandatthesametimestay
withinthepressurewindow
•MPD is designed to maintain the
wellbore pressure slightly above the
formation pressure or walking the line
method making it possible through the
useofachokemanifold
•Underbalance Drilling (UBD), on the
other hand, is basically intentionally
drillingbelowtheporepressure,thereby
allowingthewelltoproducewhiledrilling
•When drilling underbalanced the
hydrostatic head is lower than the
formation pressure and the drilling fluid
doesnotactasawellbarrier,therefore,
formation fluids are allowed to flow
continuously into the wellbore during
operations
©2015Weatherford.Allrightsreserved.
©2015Weatherford.Allrightsreserved
ManagedpressureDrilling
MPDVariants
The goal of Managed
Pressure Drilling
(MPD) is to control
the pressure profile
in a way that
eliminates many of
the drilling and
wellbore stability
issues that are
inherent to
conventional drilling
Pressurized Mud-Cap (PMCD) MPD enables
high ROP, less flat time and lower-cost drilling
in extreme-loss situations
Constant Bottom Hole Pressure (CBHP) MPD
reduces NPT and enables fewer and deeper
casing strings when “drilling windows” are
narrow or relatively unknown
Dual Gradient (DG) MPD enables total well
depth in the right hole size in deep-well and
deepwater drilling. Hydraulically speaking,
tricks the well into thinking the rig is closer
Returns-Flow-Control (HSE) MPD reduces risk
to personnel and the environment from drilling
fluids and well control incidents
©2015Weatherford.Allrightsreserved.
©2015Weatherford.Allrightsreserved
ManagedpressureDrilling
PressurizedMudCapDrilling(PMCD)
PressurizedMudCapDrillingwillallowdrilling
aheadwithoutdelayifmassivelossesare
encountered:
nTheannulusisclosedatsurfacewiththerotating
controlhead(RCD)
nDrillstringinjectionisswitchedtoseawater
nSeawaterispumpeddowntheannulusto
maintainholefillandpreventgasmigrationupthe
annulus
nFluidandcuttingsarelosttotheformation.
nBack-pressureontheannulusmonitoringonRCD
ensuresthatthewellisfull
nAllowsmonitoringofgasmigrationfromchanges
inannulusbackpressure
nAlighterdrillingfluidmeansincreasedROP,
savedrigtime,lesscostlymudlosses,avoidance
ofdifferentialsticking,lessformationdamageand
overallreducedwellcosts