Applying multiwell normalization in open hole log analysis

Abstract

A major problem when analyzing open hole well logging data in large fields is the fact that the logs were run using different logging service companies, using different logging tools over a long time span. To obtain correct log interpretations, the logging data must be depth shifted, borehole corrected, then normalized. The normalized data can then be analyzed using modem interpretation methods to obtain consistent results from well to well. Well logs provide the data that allow geologists and engineers to characterize layered reservoirs. To integrate log analysis with core, well test and production data, the logging data must be consistent. To correct calibration errors and develop consistent data, the logging data must be normalized. Significant improvements in well log analysis methods, improved stratigraphic interpretation and reservoir delineation are possible when consistent logging data are available to the analysts and geologists. Practice in using well log analysis as part of integrated reservoir studies has shown that a process called multiwell normalization is necessary to ensure that results are accurate, consistent and comparative well-to-well. The objectives of this research were to explain the need for correcting and normalizing log data, illustrate how log normalization should be accomplished, and illustrate the use of log normalization using a field case history.