Equivalent Source Method In The Time Domain Induced Polarization Method Application Study

In field theory, field and field source has a unique relationship. But in reality, theobserved field is just a portion of the field. Coupled with the observation error andrandom interference, the interpretation of observation value inevitably has ambiguity..In other words, there are many possible distribution of the field source correspondwith the observation field within a certain error range. Ambiguity leads to difficultiesin interpretation and the inaccurate of final results. If the field source whichcorresponded with the observation field is not the true source of field, we called it theequivalent source. In general data interpretation, the ambiguity has brought manytroubles, So we use equivalent source to transform the potential field, in order tohighlight the useful information, increase explanatory means, and it is very importantin the interpretation of complex anomalies.So far, the equivalent source used in the gravity and magnetic potential fieldtransformation has achieved a very good result. But the studies and the applicationsare not found in the electrical data processing. The electric field is much morecomplex than magnetic and gravity field, so the research exists a certain degree ofdifficulty. Considering electrical prospecting observation in IP method using centralgradient array, when the current electrodes are far enough, and the measuringelectrode is in the center area of two current electrodes, the electric field can beregarded as uniform field. It content the premise that using equivalent source toprocess and research.The paper mainly study results:(1) It derived spherical polarizable body of ladder IP volume formula ofhorizontal and vertical derivative of first order, two order derivative in theory. Used a single sphere model theoretical calculation and different potential field conversionresults, to show the effect of the equivalent source method. And described theequivalent source method in the field of application and effectiveness.(2)The equivalent source method applied to the electric field can extract theuseful information from the low signal abnormalities of complex superimposedmultibodies. That means we separated multitarget from complex anomalies for twogroups of different model test, and compared the results and the theoretical calculation,proved the correctness of the method.(3)Finally, through a series of calculations and tests, it proved that the equivalentsource method using in electric field is feasible and effective, and it proved that themethod has high precision and the advantages that can distinguish the complexanomaly.