Optimization of PRBS Coded Transmitting current Parameters for Electric Source and Array receiving TEM

According to Archie's formulas, the bulk resistivity of a reservoir rock depends on its porosity, pore fluid resistivity, and saturation. We use electric source TEM measurement to monitor the hydrocarbon reservoir. For the reason of improving the signal-noise-ratio we use a PRBS coded as transmitting waveform. In order to estimate the after transmitting response, we superpose the Step responses, which individually takes place at the time when the direction of transmitting current is reversed corresponding with the PRBS sequence and extend till the end of measurement. And then we distinguish the monitoring field into several zones and for each zone we select adapted transmitting parameters, namely clock frequency, the end run length and sequence order.