Geophysical drillhole logging

Geophysical borehole logging enables surveying of physical properties at greater depths of the subsurface and higher resolutions than ground surveys. Logging can therefore be used to define the depth to geological interfaces that have a distinctive geophysical signature; Provide means for correlating geological information between boreholes and obtain information on the in situ properties on or in the vicinity at the borehole wall. Logging can also assist in interpretation or constrain modelling of ground based measurements. Borehole logging is therefore an important complement to ground surveys since it increases the knowledge of mineralisations and rock mechanical properties deep down in the bedrock.

GeoVista possess a borehole logging equipment from Advanced Logic Technology (ALT) with probes to measure magnetic susceptibility (e.g. estimation of the Fe % in sections), 3-component magnetometry for localisation of magnetic bodies (e.g. iron ore). The probes for electrical resistivity and induced polarisation (IP) are suitable for detection of sulphide mineralization and rock mechanical properties.
The density probe can be used to estimate the density of the formation/mineralization. The natural gamma probe is used for lithological classification as well as detection of radon in fracture zones, but is also used for length adjustment between different probes and tools. We can also offer TEM-surveys in boreholes using our VECTEM V-probe. Our winch has a maximum depth of 1400 m. The logging equipment can easily be complemented with other probes, e.g. TV-monitoring, acoustic televiewer (structures), temperature, deviation surveying, water resistivity etc.

Reference projects:

– Estimating Iron (Fe) concentrations in boreholes in Kiruna and Malmberget (LKAB) from magnetic susceptibility and density data.