Geological structures from televiewer logs of GT-2, Fenton Hill, New Mexico: Part 3, Quality control

Abstract

A procedure has been developed for extracting geological structures from paper prints of intensity-mode televiewer logs. It was applied to old logs of drill hole GT-2 at the Fenton Hill, New Mexico, Hot Dry Rock Site. A series of tests have also been developed for measuring the resultant data quality, and this report describes these tests and applies them to evaluate the procedure. A test for measurement accuracy shows that locations were measured to better than 0.1 ft and orientations to within 1/sup 0/. The root-mean-square error in fitting a trace rarely exceeded 0.2 ft. The second set of tests, for reproducibility, measures the amount of association between two different runs of the same length of hole, in this case a distance of 275 ft. Two new measures of association are defined, termed coplanarity and collinearity. The lack of any recurrences requires explanation and leads to a third set of tests, for repetition rate. The low repetition rate is explained by random errors in location and orientation, which are different on each run. A fourth set of tests consists of fitting a model of the feature-extraction process to the data and estimating data reliability from quality parameters of the model.more » A perception model yielded an estimate of data quality at 91.5%.« less