Measurement While Drilling (MWD)Geohazards Forum 2016

Knoxville, TN

Benjamin S. Rivers, PE

Geotechnical Engineer

FHWA – Resource Center

August 8, 2016

Topics

BackgroundOverview of several studies and case example:• Gui, Soga, Bolton, and Hamelin – 2002

“Instrumented Borehole Drilling for Subsurface Investigation”• Laudanski, Reiffsteck, and Benoit, – 2013

“Experimental Study of Drilling Parameters Using a Test Embankment”

• US 281 – FM 1604 Interchange, San Antonio, TX• Florida DOT and UF: David Horhota (PM), Mike McVay (PI) – 2016

“Drilled Shaft Resistance Based on Diameter, Torque and Crowd”Take-AwaysThoughts on Future Work

Special Thanks

Elizabeth Smith, Senior Principal, Terracon“Multi-Faceted Site Investigation in Karst Terrain for Foundation Design” – TRB 2015

Measurement While Drilling (MWD) - Background

AKA – Diagraphy Drilling, Instrumented Drilling, Use of Drilling Parameters

Predominantly used with rotary-percussive, air-rotary and rotary-wash drilling

ACIP Piles - Use many of the same drilling measurements

Often used in conjunction with LWD – Logging While Drilling (down-hole geophysics) in the Oil/Gas/Mining Industries.

Background - Measurements

Measured and Recorded while Drilling:• Fluid Pressure• Torque• Rotation Speed• Thrust-on-bit (i.e. Down-thrust, Down-

Pressure, Crowd)• Hold-Back• Penetration Depth• Time• Drilling-Speed (reciprocal of time)

Approximate Timeline of MWD

Oil & Gas Industry

Deep, Off-Shore Drilling

Mining Industry

Tunneling and Grouting Operations

Directional Drilling, Trenchless Technology

Geotechnical (Emerging)

Literature50s to 80s

Late 90s

Early 2000s

Mid 2000s

Early 2010s

Gui et al. 2002

Evaluated MWD using ENPASOL system

Kennington Park, London, UK

From Gui et al. 2002

From Gui et al. 2002

v = Vd/(dD)

f = W’/(Tq/D)

easy = -v/f

hard = 1/easy

E = logv/logf

From Laudanski et al. 2013Looked at…• Multiple bit types & CFA• Rotary and

Rotopercussion• Test Embankment with

multiple materials• Compound Parameters• Comparison with some

insitu tests

From Laudanski et al. 2013Comparison of normalized energy En with different tools.

From Laudanski et al. 2013 (Cont’d)Comparison of normalized energy En with different tools.

US 281 – FM 1604 Interchange

Project in San Antonio, TX

Geology – Edwards Limestone

Known karst habitat within ½ mile radius of the interchange

From Smith 2015

From McVay et al. – 2016

Related Drillability Strength, Ds, (Karasawa 2002) and Specific Energy (Teale 1965) to Unconfined Compressive Strength –Note: Plot Shown is controlled lab tests with Synthetic Limestone

Ds = 64NT2/Fud3

N, Rotation SpeedT, TorqueF, Crowdu, Penetration Rated, bit diameter

From McVay et al. –2016

Estimated strengths from field MWD “Monitoring Strengths” and unconfined compressive strengths from core specimens.

Take-Aways

Standardized in Europe - ISO/DIS 22476-15.2 – (Balloting Process)

Most Basically, MWD provides…• Continuous quantitative drilling record• Means to assess site variability• QA value

Take-Aways (Cont’d)

Immediate Applications• Karst Features• Detecting Boulders, Lenses, Bedrock Interfaces• Characterization of Piedmont Residuum and PWR• Stratification and material identification

Potential Future Work

Understanding interdependencies while maintaining production:• Between drilling parameters• Bit types and size• Drilling methods

Correlations to engineering index parameters

Thanks!

Questions?