Geotechnology’s Geophysics Group has recently purchased new borehole natural gamma, spontaneous potential (SP), and resistivity tools, in addition to an acoustic televiewer (ATV). With these borehole geophysical tools we provide valuable data for advanced geologic projects requiring evaluations such as stratigraphic profiling, joint/fault analysis, water resource/water production evaluations, contaminant migration mapping, and rock strength assessment.
The ATV (QL40-ABI) allows us to image detailed features on the inside wall of bedrock core holes. Now we can ascertain in situ widths of solution features and the presence of void-space or in-filling material. In addition, we can accurately determine the attitudes of planar features that intersect the corehole. Now we can plot and analyze the orientation of fractures between different borings or at different levels within borings. (The areas depicted in blue on the adjacent figure represent clay filled partings and the red lines depict bedding planes and joints).
SP and resistivity logs are collected using a QL40-ELOG tool. The ELOG records four resistivity measurements (at electrode spacings of 8”, 16”, 32” and 64”), SP and single point resistance (SPR) in a single pass. This data is useful in groundwater studies to determine water production depths, aquifer thickness, water quality and permeability.
We use another tool, the QL40-GR, to record the natural gamma radiation emitted from geologic formations. This is a great tool for detecting clay and shale layers.
Geotechnology has a long history of providing valuable borehole geophysical data for our clients and we continue to develop our capabilities by acquiring new equipment. These new borehole geophysical tools allow for even better borehole correlation with our surface geophysical data.