Electromagnetic Propagation Logging: Advances in Technique and Interpretation

Abstract

ABSTRACT The Electromagnetic Propagation Tool (EPT*) is a downhole microwave instrumentation device which channels 1.1 GHz energy into the formation and measures the travel time and attenuation of the microwave signal as it propagates through the invaded zone. The relevant electromagnetic field theory, the basic measurement technique, and the tool block diagram are reviewed. The present interpretation techniques are then discussed, followed by several log examples which show the utility of the EPT. Specifically, the EPT-derived porosity, when compared with neutron/density porosity, allows one to distinguish between hydrocarbon-bearing and water-bearing zones in formations having varying lithologies and water salinities.