Experimental choice of signal-code sequence for measure while drilling under real noise conditions

Horizontal drilling is impossible without measure while drilling and logging while drilling (MWD-LWD) systems. Telemetric systems differs by transmission medium that can be wired, hydraulic, acoustical, electromagnetic, or combined of them telecommunication channel with its own merits and demerits. The main demerit of electromagnetic channel is low noise immunity that leads to problem of bit rate enhancement, and large variety of disturbers with their parameters, limiting important factors such drilling depth, accuracy and rate of drilling. This work presents results of development and realization of error-correcting coding signal for MWD-LWD systems. The tests were produced for both urban area and real drill site. In addition, comparison results for offered and conventional device manufactured by LLC "TechGeoBur". During the experiment following units "noise immune coder" of transmitter and "demodulator - decoder" of receiver were modified. Correct test requires comparison of reading been coded by different codes under the noises with the same probability parameters and the same channel distortions. Therefore, a new format of data frame was designed to solve this problem. Conclusive comparison results are represented in table where various reliable values of telemetric parameter "Gravity Toolface" are shown.