The last few years have brought on the inclusion of natural gamma ray spectral logging devices as an integral part of optimized wireline logging programs. Recorded in both open hole and cased hole environments, such logs have proven invaluable in solving the complex interpretation problems encountered in many wells. Interpretive concepts have advanced both at the wellsite and for detailed digital analyses at central processing centers.

Current wellsite evaluation techniques, as well as several recently developed digital interpretive methods for shaly sands and complex and fractured reservoir rocks, will be discussed. Inherent environmental constraints of natural gamma ray spectral logging devices are also highlighted.

Keywords:
spectral, ray spectral, mineral, feldspar, uranium, reservoir, potassium, application, ray spectral data, shale
Subjects:
Formation Evaluation & Management, Open hole/cased hole log analysis
Copyright 1982, Society of Petroleum Engineers of AIME
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