Drill Bit Parameters

MONITORING DRILLING BIT

PARAMETERS PARAMETERS

ALLOWS

OPTIMIZATION OF DRILLING RATES

V.C. KELESSIDIS - P. DALAMARINISsk l1@h tm il mvaskel1@hotmail.com

Technical University of CreteMineral Resources Engineering

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

Research aim

Optimization of drilling ratesLess expensive and safer drilling practicesH d b th l i i t ll Hydrocarbon, geothermal, mining, water well drillingMultitude of parameters affecting drilling performanceperformanceAvailability of data and proper modeling softwareOptimum combination better drilling ratesOptimum combination better drilling rates

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The problemDrilling allows for access to subsurface target areastarget areasPythagoras saying ‘whoever digs, finds, he who never digs will never find’never digs, will never findDrilling is expensiveOptimum drilling practice arrive to target in the most economical way, but with safetyy yMain monitoring parameter – Penetration Rate (m/h)(m/ )Depends on two main groups

FormationFormationDrilling parameters 33

Main parametersFORMATION

Local stressesLocal stressesRock compactionMineralogical contentFluid pore pressureFlu d pore pressure

DRILLINGDRILLINGWeight on bit and torqueRpmHydraulic parametersy p mBit condition

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Modeling drilling process - TealeRock-bit interactionEnergy to the bitEfficiency of energy transferff y f gy f

( )( )( )AWOBDRPMWOBSE bitt

/8 μ+=ENERGY PER

ROPASE

bitt +

UCS

UNIT VOLUME

ROCK-BIT MODEL tSEeff

UCS=

( ) ( )( )WOBUCS

AbitWOBDRPMROP =/)(8 μ

55AbitWOB

effUCS

−

Payzone simulatorDeveloped by G. Cooper, UCBSimilar to Teale’s model predictionsAdjustable parametersj p mUse of historical data for tuning

SPE 30213 36660

))()()()()(( GlengthtoothRPMtyaggressiviCfactorflowROP =

SPE 30213, 36660

))(_)()()()(_( GlengthtoothRPMtyaggressiviCfactorflowROP =

⎤⎡ ⎞⎛⎞⎛curv

( ) ⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛⎟⎠⎞

⎜⎝⎛−−=

lengthtoothDUCSWOBG

curv

*4.012exp1 5.2

66

( ) ⎥⎦⎢⎣ ⎠⎝⎠⎝ g_

Comparison of models with lab data

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Use of historical data

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Data neededLithologyBit records and bit typesCasing scheduleCasing scheduleDrilling parameters

WOB, RPM, FLOW RATE, PRESSUREPRESSUREROP

Drilling fluid

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Adequate simulation

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Case study analysisDrilling in Norwegian Continental ShelfReconstruct drill time logReconstruct drill time log1917 – 2414 mFour main lithologies, 18 formation intervals

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Base case and two scenarios

1.Normal drilling curve1.Normal drilling curve 2.Drilling curve with

RPM+50 rpmRPM+50 rpm3.Drilling curve with

WOB+45 kNWOB+45 kN

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Full scenarios

1 B d illi ti l t1.Base drilling time plot2.Simulated drilling time

l t b h i t 4 5plot by having extra 4.5 tons, extra 50 RPM and

t 200 lextra 200 lpm

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Increase in UCS by 50%

Increase may range between 58y gand 96%, giving an overall increase in total drilling time for

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gthe sections chosen for the simulation of 82%

ConclusionsPenetration rate – the most sought after

t f d i f ll d illiparameter for design of well drillingAttempts to simulate the process – none very successfulRecent advances, flexible simulators that , fcould be used on sitePayzone is one of them (G Cooper)Payzone, is one of them (G. Cooper)Drilling advance model, few adjustable parametersparametersCan be tuned via use of prior historical data f th i d th fi ldfrom the region and the field

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ConclusionsData: WOB, RPM, Flow, well geometry, drill bit record, ROP, LithologygyNormally monitored – need to monitor in non-critical wells alsocritical wells alsoCan be used to effectively model and describe the drilling processthe drilling processRe-engineering and re-drilling possible, no reat difficultiesgreat difficulties

Increase in WOB, RPM, Flow -> beneficial ff d b bi effect, need to worry about bit wear

Increase (error) of UCS by 50% decrease yin ROP by 82%

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