Development Of High Precision Dynamic Monitor Of Fluid Between Oil Wells

In petroleum exploration and development, the DC current is usually put into oil well and detect the weak voltage in surface which can deduce earth resistivity .In this way, the direction of dynamic fluid can be indicated, which contain electrolytes and is put into oil well. It can also indicate the distribution of remaining oil.The voltage acquisition system should detect the surface voltage at the background of strong noise. Here we use the pseudo-random code which is based on spread spectrum theory to modulate the DC current putting into oil well, and then use the relevance principle to suppress noise and improve detection precision. The constant-current source apply the MSP430 microprocessor as the core of variable parameters fuzzy PID controller to keep the current constant when load is changing.The circuit of the acquisition system includes amplification circuit, filter circuit, A/D conversion circuit; the software assumes responsibility for controlling the equipment, processing the digital signal, de-spreading with relevant algorithm. Constant current power supply includes the thyristor rectifier circuit, monitor and control circuits based on MSP430 microprocessor. The software achieves the variable parameters fuzzy PID controller in order to control the trigger angle of thyristor. Finally, we verified the performance of devices under the laboratory conditions and analyze the result.