method of determining a borehole surrounding erdformationen with the help of the gammastrahlenspektroskopie

摘要

In a well logging system, gamma ray energy spectra provided by a radioactivity logging tool are each compared with a composite standard spectrum, derived by combining standard weighted spectra, at a number of energy levels at least equal to the number of constituents postulated, the comparison being repeated with successive variations in an energy-to-intensity characteristic of the composite spectrum until the best match is obtd. between the latter and the spectrum from the logging tool. Comparison pref. proceeds by application of a least-squares technique.