SonicScopeThe Next Generation ofSonic While Drilling

Meretta Qleibo

LWD Petrophysics Domain Champion

2

Agenda

─Quadrupole: Why? and How?

─Introduction to Sonic Scope

─Local Example

─Summary

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Why Multipole? Why SonicScope?

─GoalProvide high data quality in real time

Deliver a robust compressional and shear measurement for allformations, irrespective of mud type

─Obtaining reliable compressional and shear providesPore pressure trends

Borehole stability analysis

Gas detection/saturation

Advanced drilling optimization/fracture gradient

Advanced formation evaluation

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From Monopole to Multipole

SonicScope• Multipole tool

• Vp & Vs in all formations

• Enhanced real-time delivery

• Stoneley

sonicVISION• Monopole tool

• Enhanced real-time delivery

• Vp & Vs in “fast” formations

iSONIC• First LWD sonic tool

• Monopole tool

• Vp only

1996

2004-2008

2008onwards

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DipoleMonopole Quadrupole

Review of Borehole Acoustic Modes

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Dispersive Waves, Flexural and Quadrupole Modes

─ Slowness of the wave varies with frequency

Stoneley wave

Dipole flexuralwave

Quadrupole wave

Dipole flexuralDipole flexural QuadrupoleQuadrupole

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Why Quadrupole and Not Dipoles for LWD?

Wireline tool Drill Collar

Frequency

Wirelinetool flexural

Borehole flexural

Formation shear

No interference

Wireline dipole

Slo

wn

ess

Collarflexural

StrongCoupling

LWD dipole

Slo

wn

ess

Frequency

Fast collarflexural mode

Boreholeflexural mode

Boreholequadrupole

Collar quadrupole

Slo

wn

ess

LWD quadrupole

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SonicScope 825 – Key Technologies

• 12 levels spaced at 90 degrees, 48 receivers total• Industry best 4” inter-receiver spacing, aliasing completely eliminated• Signal digitized at the receiver enables faster downhole processing• 4 bulkheads vs. 28 for QBAT = stronger collar, simpler acoustic modeling

• High power to excite Quadrupole in slow formations• Situated close to the receiver section to overcome attenuation

• Monopole collar arrival suppressed as low as possible• I.D. optimized to separate QP propagation modes• Enables Automatic Labeling, STC threshold

Dual Layer Quadrupole Transmitter “G42” Receiver Belts

Screw on Centralizers Optimized Attenuation Section

• Ensure mode purity• Wellsite Changeable• Hard Faced

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Quadrupole Shear Inversion

─ Model-Based Inversion

Dispersive approach

Account for tool presence effect

─ Tool Presence

Tool equivalent model

Includes all tool details

─ Quadrupole Inversion Methodology

Homogeneous Isotropic model

Tool equivalent model

Maximizing the semblance

Boreholequadrupole mode

Mode Search RZX Modeling

Note: Size of the dots indicate energy

Frequency (kHz)

Slo

wn

ess

(us/

ft)

Shear value

Modeled Quadrupole Mode

Real Quadrupole Data

Slo

wn

ess

(us/

ft)

Frequency (kHz)

Shear value

Model HI

Measured Data

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Local Data Review – SonicScope825

North West Shelf well

12 ¼” hole section, near vertical

Fast and slow formations

Wireline logging suite included Sonic Scanner

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Compressional delivered in real time

Coherency plot and pumps off transmitted toenable QC of the data

Pumps off test performed every stand

Real time applications include seismic tie ins,pore pressure modeling and geomechanics

Real Time Operations

40 us/ft 240

PS

P

(RT)DTCO, DTSM

(RT)

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Data analysis of high-frequency monopole

PS

Stoneley

SlowFormation

P St

P S St

P

S

St

P

St

FastFormation

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Data analysis of high-frequency monopole

FastFormation

SlowFormation

P St

P S St

P

S

P

St

St

P

S

St

P

St

S

P

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Shear from Quadrupole Inversion

Shear slowness

Homogeneous IsotropicQuadrupole dispersion curve

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LWD(RT)

LWD(REC)

WL

• Comparison between SonicScope Realtime, memory data, and Sonic Scannerlog (Monopole only)

• Memory data from SonicScope and SonicScanner show excellent agreement

• Real Time data quality is as good asmemory mode data

• Shear data is available in Real Time fromMonopole only (fast formations)

Sonic Scanner ComparisonFast Formation, Monopole

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• Comparison between SonicScope 825Real time, memory data, and SonicScanner log (Monopole only)

• Monopole data in slow formation will not giveshear if Shear DT > Mud DT

• Compressional from Monopole approachingmud DT requires Leaky-P processing

LWD(RT)

LWD(REC)

WLSonic Scanner ComparisonSlow Formation, Monopole

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• SonicScope Quadrupole shear shows anexcellent match to Sonic Scanner Dipoleshear

• Shear DT acquired up to 540 us/ft

LWDQuadrupole

WL DipoleSonic Scanner ComparisonSlow Formation, Quadrupole

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• Sonic Scope service is now available in 4.75” and8.25” collars

• Robust compressional delivered to client in real time

• High quality waveforms enable data analysis and QC

• Excellent Agreement between SonicScope andWireline Sonic Scanner

Summary

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SonicScope

─ Latest Schlumberger Generation of Real-Time LWD Sonic

─ High Quality Monopole Data

─ Multipole Capability

─ Available in 4.75” and 8.25” collars