Method for the determination of clay and mica concentrations in subsurface sandstone formations through radioactive logging

摘要

A subsurface sandstone formation is logged to provide a record of the natural gamma radiation of the thorium, uranium, and potassium trace elements in the formation. Both the clay and mica contents of an interval of interest are determined from the natural gamma- ray activities in the interval of interest, in a clean sandstone interval and in a mica-free shale interval.