Patent ID: 6619395
Filing Date: 2003-09-16
Classification: E21B

Abstract:
A method of determining at least one characteristic of an earth formation surrounding a borehole using a rotating logging tool, the logging tool having at least one emitter for emitting energy into the earth formation and at least one detector for detecting energy reflected from the earth formation, the method comprising:detecting energy during a plurality of sample periods with the detector to produce a plurality of samples corresponding to the sample periods, wherein the duration of each sample period is shorter than one half of the time required for the tool to complete a rotation; measuring the azimuthal angle of the detector in at least one sample period; measuring the standoff of the detector from the wall of the borehole in at least one sample period; sorting the samples into groups, each group representative of the azimuthal sector of the borehole from which the sample was detected; within a group, mathematically weighting each of the samples according to standoff; within a group, mathematically summing the weighted samples to achieve a weighted sample total for a sector; within a group, dividing the weighted sample total by the total duration of sample periods in the group to determine a detection rate for the sector; and transforming the detection rate for at least one sector into a representation of at least one formation characteristic.