Borehole penetration of rock strata in the shallow subsurface is designed to recover representative samples for chemical and physical tests, to provide an access conduit for sophisticated indirect testing with geophysical sondes, or to provide a conduit to a specific subsurface horizon for extraction purposes. Variations and combinations of these drilling logics may be dependent on drilling depths. Shallow subsurface borehole drilling is usually considered within 300 m of the surface. It is usually directed toward exploration and production in sedimentary terrains within the disciplines of groundwater hydrology, Pleistocene geology, coal and oil shale exploration and delineation of industrial mineral deposits, and corresponding delineation of metallic ore bodies in igneous and metamorphic regions.
The major categories of subsurface drilling techniques are normal rotary, rotary coring, and reverse circulation. Each methodology is designed to provide optimum benefits within several...
- Hildebrant, A. B., Bridwell, H. C. and Kellner, J. M. 1957, Development and field testing of a core barrel for recovering unconsolidated oil sands, in W. C. Goins et al., eds., Drilling. AIME Petrol. Trans. (Rept. Ser. No. 6), 271–273.Google Scholar
- Irvine, J. A., Whitaker S. H., P. L. Broughton, and T. E. Broughton, 1974, Analysis of borehole sampling methods in lignite seam evaluation, in G. R. Parslow, ed., Fuels: A Geological Appraisal. Saskatchewan Geological Society (Spec. Publ. No. 2), 203–228.Google Scholar