A canadian geophysical logging system for scientific drilling

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In attempting to understand many geological phenomena, engineers and scientists first employ a number of surface tools such as mapping and geophysical imaging to infer geological structure and lithology. However, surface techniques cannot always provide the information desired; and workers must then attack the problem by drilling and coring. One good example of where coring is necessary is in the recovery of quality lake sediments that are then studied by sedimentologists, palynologists, and paleomagneticists to reveal clues to the variations of earth's climate through the Quaternary. A different, but important, example is to obtain information on the true in situ physical conditions of tectonic stress, temperature, and fluid saturation. As such, earth scientists have increasingly turned to scientific drilling to address issues that cannot be resolved any other way. Much of this work is promoted internationally through organizations such as the Integrated Ocean Drilling Program and the International Continental Drilling Program, both of which have relied on Canadian expertise. Geophysical logging, a key component of any scientific drilling, refers to the measurement of the in situ physical properties such as electrical conductivity or of conditions (e.g. temperature) with depth along the borehole. Technically, this is done by lowering instruments into the borehole using a long steel cable called a wireline. Such information is critical in order to assist in the interpretation of the core. In cases where core cannot be recovered logging is absolutely essential. The equipment requested here will bring a substantial geophysical logging capability to the Canadian academic geoscience community for use in scientific drilling programs. In addition to many standard instruments to measure electrical resistivity and seismic wave velocities, the more specialized downhole 'tools' (i.e. instruments) requested here include the capacity to finely resolve magnetic susceptibility (for use in lake paleoclimate studies) and a fluid sampler (to obtain water from depth for hydrological and geochemical studies), and an ultrasonic borehole televiewer to image the borehole shape, to orient fractures, and to assist in orienting core.