Design Of Multi-parameter Formation Water Resistivity Logging Tool Receiver

For the oil and gas reservoir evaluation of shaly sand exploration well and the residualoil saturation evaluation of high water content oil field, the formation water resistivity andcation exchange capacity are extremely important parameters. The electrochemicalcharacteristic parameters polarizability curve and the spontaneous potential curve could begot from the logging data. Based on the model of polarizability and spontaneous potential,formation water resistivity and cation exchange capacity could be calculated. With the abovemethod as a foundation, a multi-parameter formation water resistivity logging tool receiversystem was designed on the basis of the Induced Polarization principle. It can be used tomeasure Polarizabilty, spontaneous potential and formation resistivity through one-time welllogging. Then, effective evaluation could be made for residual oil saturation and residual oilreserves.In this receiver system, the master and slave structure between DSP and FPGA wastaken as the core; the multi-channel structure design with different gains was used forformation potential measurement; parameter control was adopted in the Logging flow; themethod of CAN communication was applied in Interactive communication. Besides, thespontaneous potential compensation technology was adopted to eliminate the offset of themeasured potential.In this thesis, firstly, based on the induced polarization effect and spontaneous potentialcauses, specific logging implementation method of the receiver system was introduced.Secondly, the overall function architecture of the logging tool receiver system was designed.Particularly, the architecture design of each function module was described in detail, fromthe aspects of data acquisition, FPGA logic control and DSP interaction control. Systemcalibration and spontaneous potential compensation method was also analyzed. Thirdly,according to the differences and similarities of the two logging modes, the integrated loggingcontrol flow with parameter control was proposed and analyzed. And the software work flowwas analyzed respectively in the respect of FPGA and DSP. Finally, the system experimentwas carried out from the following three aspects: the overall system joint debuggingexperiment, high temperature accuracy experiment and spontaneous potential compensation experiment. According to the results, the following conclusion can be achieved: the receiversystem realized high-precision measurement of wide dynamic range; the logging mode andtiming sequence are flexible and adjustable; the receiver and host system can complete thereal-time bidirectional communication.