The operation of hostile environment logging tools at temperatures up to 250° C stresses not only the tools, it also places severe demands upon the wireline telemetry due to the wide variations in the logging cable transmission characteristics. A robust adaptive wireline telemetry system for use in hostile environments has been developed that combines sophisticated digital communication methods with modern Digital-Signal-Processing (DSP) techniques. The downhole telemetry transmitter outputs a multilevel signal. The uphole receiver includes an adaptive transversal-filter equalizer (TFE) that is continually optimized to correct for changing signal distortion. The system was designed to operate robustly at high data rates over the temperature range of 0 to 250° C.

Keywords:
receiver, equalizer, well logging, coefficient, telemetry signal, telemetry system, frequency band, upstream oil & gas, cable, distortion
Subjects:
Formation Evaluation & Management, Information Management and Systems, Open hole/cased hole log analysis
Copyright 1992, Society of Petroleum Engineers
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