Water-Resources Investigations Report 98-4184
Version 1.1
November 2008

Table 3. Types, properties measured, and application of geophysical logs used in Oasis Valley, Nevada (modified from Keys, 1990)

Type of log

Properties measured


Caliper Borehole diameter Provides borehole corrections for other logs, lithology, fractures, and hole volume
Natural gamma Gamma radiation from natural sources in formation Assists in the identification of lithology and stratigraphic correlation; may be related to clay content
Dual induction, multi-electrode, resistivity (conductivity, resistivity, short- and long-normal resistivity, and lateral resistivity) Apparent resistivities of formation at different distances from borehole Assists in the identification of lithology and stratigraphic correlation of units; provides qualitative or relative data on water quality
Single-point resistance Resistance of formation and fluids in borehole and adjacent formations Assists in the identification of lithology
Spontaneous potential Electric potential between fluids in borehole and adjacent formations Defines lithology, clay and shale content, and formation water quality
Acoustic velocity Compressional-wave velocity through fluids and formations Helps determine saturated zones, water levels, and lithology; indicator of fractures; used to estimate primary porosity
Fluid (temperature, fluid resistivity, and specific conductance) Temperature, resistivity, and specific conductance of borehole fluids Quality of borehole fluid, flow in borehole, and geothermal gradients
Acoustic televiewer Acoustic reflectivity of borehole wall Lithology determination; fracture location, width, orientation and character, strike and dip of beds. Additional processing provides deviation from the vertical of the borehole
Heat-pulse flowmeter Vertical flow within the borehole In-hole flow from fractures; apparent hydraulic conductivity of permeable zones