Tuesday, April 1, 2008 : 2:40 p.m.

Characterization of Fractured Bedrock Using Advanced Oilfield-Developed Borehole Electrical Resistivity Imaging and Full Waveform Sonic Technology

Edward A. Clayton and Timothy K. Parker, PG, CEG, CHG, Schlumberger Water Services

The estimation of hydraulic properties of fractured rock formations presents unique challenges. Key fracture system parameters such as dip, azimuth, intensity, and aperture are dependent upon complex interactions between rock characteristics and applied stresses. Developing an understanding and representation of fractured formations for use in assessing and managing groundwater resources is a challenging multi-disciplinary activity requiring state of the art techniques including field sampling, data integration, geologic modeling, hydrologic test analysis, and predictive flow modeling. High resolution electrical resistivity imaging tools can be run in uncased boreholes filled with water or mud for to provide a fully oriented formation electrical property image (“virtual core”) surrounding the borehole. This quantitative imaging data can also be used for geomechanical analysis of aquifers and identification of drilling-induced features such as breakouts. Primary applications of high resolution electrical resistivity imaging data in fractured bedrock are the identification of: (1) structural dips and strikes of fractures/faults and bedding, (2) fracture apertures, (3) lithologic boundaries, (3) paleocurrent directions, (4) stratigraphic anisotropy, (6) grain-size, (7) carbonate texture, and (8) secondary porosity. Full waveform monopole and dipole sonic logging tools can be run in uncased, or cased and cemented, boreholes filled with water or mud to provide comprehensive characterization of the acoustic properties in the formation that are related to rock mechanical properties, existence and type of fractures, rock heterogeneity and anisotropy. These tools emit and measure multi-frequency sonic waveforms (compressional, shear and Stoneley), traveling through the formation surrounding the borehole. Processed outputs obtained are the velocities and the amplitude or energy of each waveform, which can be used to determine a variety of formation parameters including matrix porosity and dynamic elastic moduli (i.e., Poisson ratio, Young’s modulus) in open or cased boreholes. Application and integration of these methods into a few case studies will also be described.

Edward A. Clayton, Schlumberger Water Services Mr. Clayton provides technical consultation on groundwater and water resource management issues, offering expertise in hydrogeologic characterization, groundwater and integrated systems modeling, geophysics, and project management. Mr. Clayton’s qualifications and experience include: Master of Applied Science degree in Hydrogeological Engineering from University of British Columbia, Vancouver, Canada; Master’s thesis research centered around accounting for uncertainty in hydrogeologic characterization and decision making; BS in Geological Engineering from Princeton University, New Jersey; lead technical analyst and project manager for hydrogeologic characterization programs using advanced geophysics and subsurface modeling software at Los Alamos National Laboratory, New Mexico, California, southern Florida, and Brazil.

Timothy K. Parker, PG, CEG, CHG, Schlumberger Water Services Mr. Parker is a Principal Hydrogeologist with Schlumberger Water Services in Sacramento where he is working to assist adapting Schlumberger’s advanced oilfield subsurface characterization tools and technologies to the groundwater industry . Mr. Parker is currently a Director, Legislative Committee Chair, and Past President of the Groundwater Resources Association of California (GRA); Director of the American Ground Water Trust; and serves as a Director on the AGWSE Division, NGWA. He is a California Professional Geologist, Certified Engineering Geologist, and Certified Hydrogeologist. Mr. Parker co-authored the book “California Groundwater Management’, second edition published by GRA in 2005.


2008 Ground Water Summit