Challenges Drill Fluids

DRILLING FLUID CHALLENGES FOR DRILLING FLUID CHALLENGES FOR OIL-WELL DEEP DRILLING

Vassilios C. KELESSIDISsk l1@h tm il mvaskel1@hotmail.com

Technical University of CreteMineral Resources Engineering

SGEM 2009SGEM 2009Albena, June 14-19, 2009

Research aim

Develop smart drilling fluidsAdaptable to harsh conditionsH il bl t h i s f ti l Have available techniques for optimal measurements of fluid properties, particularly rheologyDevelop hydraulics models for pressure drop Develop hydraulics models for pressure drop prediction along the wellboreBetter understanding efficient cuttings transport in a multiphase environmenttransport in a multiphase environment

22

The problemDrilling depths, total (>7000 m) and water (~ 3000m) depths are ever increasing3000m) depths, are ever increasingHigh pressures (>2000 bar) and high temperatures (>3000C) are encounteredtemperatures (>3000C) are encounteredNarrow pressure tolerancesHarder rock is encountered, lower drilling ratesDemand for better drilling fluids, avoid problems -understand behavior in such hostile p menvironmentsHydraulic programs for complex rheologyHydraulic programs for complex rheology

33

Deep drilling challenges

44hard rock - wellbore stability - high P, T

MPD vs Conventional

55

Drilling fluid challengesROLE

Hydrostatic pressureHydrostatic pressureCuttings transportCooling the bitWellbore stabilityWellbore stab l ty

CHALLENGESHigh T P stable density and rheologyHigh T,P stable density and rheologyMeasurements at downhole conditionsPredictions of downhole conditionsStability of additivesy fAppropriate rheological models

66

Rheology, effect of pressure and temperaturetemperature

Low T

High T

77

Lignite additive for T control

88

‘Flat’ rheology fluids

99

Barite sag – solution ?Rheograms for micron sized barite

*116.085.4

=

=

sPaKPa

bariteAPI

yτ

*076092.0

=

=

sPaKPa

baritesizedmicron

yτ

841.0116.0

=nsPaK

854.0076.0

==

nsPaK

1010

Conclusions

Demand for more energy challenge to oil industry, deeper waters and deeper wellsExtreme environments better drilling Extreme env ronments better dr ll ng fluidsImproved drilling techniques Managed Improved drilling techniques, Managed Pressure Drilling, narrow pressure marginsGood and representative rheological models for the complex fluidspModel of choice – Herschel-Bulkley, hydraulics modeling is neededhydraulics modeling is needed

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ConclusionsTake into account effects of temperature and pressurepressureModeling for predicting temperature and pressure downholeRheological measurements at downhole Rheological measurements at downhole conditionsDevelopment of additives that withstand extreme conditionsLeading to ‘smart’ drilling fluids, adopting to

ti l i tparticular environment1212

Need to meet the challenge

1313