Future applications of elemental concentrations from geophysical logging

Measurements of elemental concentrations currently play a very small role in subsurface formation evaluation in the petroleum industry. However, new advances in data interpretation combined with new measurement capabilities indicate that the interest in elemental concentration measurements will expand rapidly in the future. In the case of fluids, the major applications are the direct detection of hydrocarbons and of soluble impurities in subsurface water. New applications have been developed for the use of inorganic chemical data in evaluating subsurface solids. These include a new normative analysis which permits a quantitative estimation of the minerals which make up the rock. In addition, the new techniques have applications in such areas as the interpretation of depositional environment and diagenesis, and the estimation of such parameters as cation exchange capacity, grain size, and even permeability. Elements are listed in order of value to the petroleum industry according to these potential applications in order to speed the necessary nuclear measurements to ensure high quality nuclear geochemical data. (author)