Method for determining depth of penetration of radioactive tracersin formation fractures

Abstract From the Canadian patent

A method for determining the mean depth of penetration of one or more radioactive tracers injected by a hydraulic fracturing process into a fractured formation disposed about a well bore as an indication of the extent of radial fractures including the steps of measuring with a radioactivity detector in the well bore at the depth of the formation fracture, the degradation of the gamma ray energy spectra of the radioactive tracer in the fractured formations resulting from the traverse of radiation through the formations and borehole to the detector; obtaining a ratio , the count rates CA and CB in two energy ranges where the range for obtaining CA is sensitive to primary radiation reaching …