A Downhole Multi-parameter Monitoring System

In order to obtain the downhole information involving ESP equipment to guide oil production, a downhole multi-parameter monitoring system based on current loop data transmission method was developed. Compared with other transmission methods in harsh environment, the current loop data transmission method possesses obvious advantage in reliability and accuracy. By ESP motor's three-phase winding and three-phase symmetrical reactance on the ground, the loop could be realized. Meanwhile, the downhole circuit could be powered by means of the loop. After conditioned by electronics in downhole circuit, the current in the loop reflected the amplitude of sampled signal and thus the signal could be extracted when the current flowed through the uphole sampling resistance. In the uphole, the circuit based on ARM7 processor supplied power for downhole circuit and filtered the received signal; while the circuit based on ARM9 processor rectified and displayed data, and its abundant human-computer interaction function make operations more convenient.