This advanced logging technology can provide detailed, depth-continuous, pseudo-core measurements of aquifer properties such as: hydraulic conductivity, total porosity, effective porosity, storativity, matrix geochemistry, pore pressure, total dissolved solids concentrations, water saturation, and clay content. These advanced tools can also be used to identify and quantify orientations of bedding and fractures, along with changes in lithology. The resulting hydrogeologic parameters can then be incorporated into conceptual hydrogeologic models to meet modeling needs.

This paper introduces the physical principles of several advanced logging technologies and their respective applications to the groundwater industry.

• Magnetic Resonance – A measure the magnetic resonance response of the free hydrogen in a formation’s pore space and is used to evaluate specific yield, effective porosity, total porosity, and hydraulic conductivity.
• Dipole Shear Array Sonic – These tools use high-quality, monopole and dipole sources and measure compressional, shear and Stoneley slowness, which are used to calibrate surface seismic data and determine stress anisotropies, geomechanical properties, porosity, permeability, and fracture permeability.
• High-Resolution Imaging – Imaging tools create fully-oriented images in 3-D space of the electrical resistivity or acoustic properties of the formation around the borehole and are used to determine strikes and dips of bedding and fractures, and to evaluate rock/sediment texture.
• Gamma-ray Spectroscopy – Measures gamma ray activity, which is used to determine elemental weight fractions of a number of key rock-forming elements and define lithology constituent percentages (e.g. sand, clay, carbonate)