METHOD FOR ASCERTAINING OPTIMUM LOCATION FOR WELL STIMULATION AND/OR PERFORATION

摘要

METHOD FOR ASCERTAINING OPTIMUM LOCATIONFOR WELL STIMULATION AND/OR PERFORATIONAbstract of the DisclosureA method is disclosed for the in situ examinationof earth formations penetrated by a borehole to ascertainthe optimum location along the length thereof for institutingwell stimulation operations or, where the well is cased, theoptimum location for perforating the casing. The methodutilizes natural gamma ray logging to determine the optimumlocations with the natural gamma ray radiation of the earthformation surrounding the borehole measured and the totalmeasurement then separated into potassium-40, uranium, andthorium energy-band signals. A differential value isderived by subtracting the energy-band signal for eitherpotassium or thorium from the energy-band signal for uranium,with the differential thereafter compared to a energy-levelstandard having a preselected magnitude. The optimumlocations for perforating and/or instituting well stimulationoperations will be those zones in which the differentialexceeds the preselected energy level standard.