Development of Wireless Downhole Pressure and Temperature Telemetry Tool. AnnualReport, April 1, 1991-March 31, 1992

摘要

The development of a wireless telemetry system for use during stimulation of gaswells is a 30 month project. The report covers the first year of the development. A laboratory prototype electromagnetic downhole transmitter and uphole receiving antenna have been assembled and tested in a test well. Modulated signals have been detected and decoded to depths of 3,000 ft in a cased well. Signal attenuation rates as a function of depth have been determined and were within expected values in cased hole. Openhole attenuation rates have been determined and are greater than anticipated. However, the signal amplitudes at 6,000 ft in openhole are approximately the same as those at 3,000 ft in cased hole. Determination of the dependence on the frequency of the electromagnetic telemetry link has not been totally determined. At 3 Hz and 6 Hz the attenuation rates in cased hole are nearly the same. Open hold rates have not been determined for 6 Hz operation. Experimental results and subsequent analysis indicate that an electromagnetic system can be developed.