Geotek Core Logger

Our Geotechnical Laboratory is centered around a GEOTEK Multi-Sensor Core Logger (MSCL) which is used to determine sediment properties (sonic velocity, bulk density, porosity, void ratios, and water content). The sediment properties measured by the MSCL may be used to assess sediment stability and utilized to optimize the location of drilling rigs, production platforms, pipelines and sub-sea structures.

A conveyor system moves the sensor array, which scans the core as it passes. The conveyor is driven by a stepper motor which can position a core to an accuracy of better than 0.5-mm. The computer controlling the conveyor also controls the sensors, so that all data are automatically correlated. The computer also measures the length of each core section and can automatically subtract the thickness of the end caps, allowing the sections to follow sequentially, producing an unbroken stream of data. The MSCL can handle core sections up to 1.5-m long and 15-cm in diameter, and can sample at 1-mm intervals.

The logger is equipped with a 137-Cs gamma source in a lead shield for determining bulk density, with a resolution of better than 1%. The logger is also equipped with 250-500 kHz piezo-electric ceramic transducers for measuring P-wave velocity, which are spring-loaded against the sample and accurate to about 0.2%. Core diameter measurements are taken using rectilinear displacement transducers, with a resolution of 0.05-mm (sleeved core).