Developments in elemental concentration logging and applications

It is noted that the past decade has seen a dramatic growth of gamma-ray spectroscopy logging as a tool for solving geophysical problems. Developments have provided absolute elemental concentrations for a larger set of elements, using elemental analysis (including tracers) for solving many specific oil-field problems and providing a basis, through geochemical research, for developing a wide range of applications of borehole elemental analyses, such as chemically described mineralogy. Physical properties have been related to the mineral structure of the formation rock, such as cation exchange capacity, grain density, permeability, and source rock evaluation. Some areas of further development, both in the techniques of elemental logging and in the applications of the data, are discussed