Experiment Research And Theoretical Analysis On Rock Induced Polarization Phenomenon

At the moment, associated with SP logging, induced polarization log (IP) is mostly used to evaluate water flooded zone as both the key parameters: formation water salinity and cation exchange capacity are the results of the electrochemical reaction. So they must be related to IP and SP. Formation water salinity and cation exchange capacity can be find out point by point used IP and SP, also the shaly impaction on calculating saturability is removed, so IP and SP are used widely in fluvioterrestrial oil field. Accordingly it is necessary to study the characteristic of Induced polarization to extend the application of IP in exploration activity.On the basis of the experiments of on rock induced polarization, affecting factors about rock induced polarization were analyzed in this paper. Through the comparison of sirt and Levenberg-Marquardt algorithm, at last Levenberg-Marquardt is used to invert polarization spectrum owing to the inversion result is better and polarization spectrum is obtained which is similar to T₂ spectrum. The polarization spectrum characteristic was analyzed under the conditions of different salinity,water saturation,spotting numbers and current supply orientation. Also experiments of on rock NMR were carried out and T₂ spectrum was gained using the Levenberg-Marquardt algorism .The results were compared to the T₂ spectrum from measurement for the sake of verifying whether the program is right. Levenberg-Marquardt program was used to invert pulsed neutron spectrum and l-m program's application was extended. The rock polarization spectrum and T₂ spectrum were compared and the result shows that both the polarization spectrum and T₂ spectrum can characterize pore throat distribution of the rock, but there is some different character .At last, the rock polarization spectrum and distribution of pore throat from mercury penetration in order to lay a foundation for the application of polarization spectrum.By means of upper research, the polarization spectrum with more log information is recognized clearly, then more technical support will be provided for induced polarization log.