04_geophys logging-TRB rev3 (Diavik added).pdf

7/27/2019 04_geophys logging-TRB rev3 (Diavik added).pdf

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Optical and Acoustic Televiewer Borehole Logging Improved Oriented Core Logging Techniques

Tom Eliassen, VTrans; Dorothy Richter, Hager-Richter Geoscience;Heather Crow, Peter Ingraham & Trevor Carter, Golder Associates


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MYTHBUSTERS


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THE PROBLEM:

Highly fractured zones and soil filled joints four

e isodes of foldin and faultin

Folded rock fabric within cut


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THE PROBLEM:

Maintaining core orientation

difficult in highly fractured

rock soil seams up to 4 to6 thick, significant core loss

Local drillers not

accustomed to double-ortriple-tube coring methods

15-foot rockfall boulder in Route 9 ditch


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LIMITED BEDROCK EXPOSURES:


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PROJECT APPROACH:

Collect joint and discontinuity data

and coring program

Geophysical borehole logging using

optical or acoustic methods

Measurement and assessment of

joint planes and laboratory testing

o core samp es.


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OPTICAL AND ACOUSTIC LOGGING:

Early logging developed in the 1960s in

processing and field equipment haveyielded highly mobile and practical

.

Good core drillin and sam lin is still

vital for verification, lab samples and to

assess joint planes


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BOREHOLE TELEVIEWERS:

Can replace Oriented Coring with

wall

Enhance geotechnical data with

high-resolution in situ images

Can be a cost effective

investigation technique


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The Logging System

Small, Portable

Laptop controlleddata collection -

QC on site

Operates

independently of


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e ev ewers: pt ca an coust c

O tical:

High-resolutiondigital image of

borehole wall

Acoustic:

Sonar ima e of

borehole wall


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Plane Slice

Through a ProducesSinusoid in the

N E S W N

Cy in er

Image


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Optical Images in Fault Zones: Collecting Data in Poor Rock

230 m

Bro

18.0 mMi

230.5 m

kenCo

re

singC

ore

231 m

19.0 m

231.5 m

Granite Shale


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INTEGRATION WITH GEOTECHNICAL DATA


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Geotechnical Data and Televiewer Images: One Log Sheet


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Route 9 Improvements, Vermont:

All Terrain Vehicle w/ Gen-Set & Tools Winch, Data Processor and La to

Caliper Tool Optical Televiewer Tool Acoustic Televiewer Tool


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I-93 Improvements, New Hampshire:


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I-93 Improvements, New Hampshire:


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I-93 Improvements, New Hampshire


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Optical Televiewer Log


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Acoustic Televiewer Log


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Televiewer Logging in New York City:

Getting there is half the battle.


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Freedom Tower, World Trade Center Site:


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Televiewer Logging New York City:

NYC Televiewer Log


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Diavik Diamond Mine


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Diavik Diamond Mine

Geotechnical drilling for pit slope

stability investigation

Televiewers introduced oriented


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Diavik Diamond Mine

Advantages: Structural data where its most needed

Zone of Broken Core

Televiewer

interprets data

reliably in

Core Photograph

fracture zone


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Diavik Diamond Mine

Primary Benefits:

Costs reducedfewerstaff, fewer hours on site,

logging

greater confidence in

structural orientations,

,

comprehensive log

sheets


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Tuen Mun Road - Hong Kong

Acoustic and impression packer

core orientation foam coring

Six ma or sheet oints in

micro fractured granite

9000 vehicles/hr Six Lanes


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WellCad Televiewer Tools:

Virtual cores can be

developed from televiewer

mages an v ewe rom a

angles

Virtual Acoustic Core - NYCVirtual Optical Core - VT


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Example Virtual Core plots from OPTICAL Televiewer

Fractures

with

Calcite Veins

in Fault Zone

Soft Clay Interval

Within a Fault Zone

terat on

Valuable for:

DesignCalcite Veins in

DataInterpretation

Contractor

Fault Zone

bidding


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Televiewer Project Considerations:

OPTICAL TELEVIEWER

Borehole diameter 3 12 inches

Clean borehole clear fluid or air filled

good results in air rotary boreholes

ACCOUSTIC TELEVIEWER

borehole diameter 3 12 inches

Logging has produced excellent results in diamond drill andgood - fair results in air rotary boreholes


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Borehole Televiewers: What can be gained?

Accurate structural orientations of

boreholes

improved geotechnical information

traditional oriented core methods


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Challenges Ahead

Televiewer Information; and

Joint Set Data Synthesis.


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Questions?

The best part about trees in Vermont .

04_geophys logging-TRB rev3 (Diavik added).pdf

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