The Elastic Impedance Log Estimation Puzzle

There is always some confusion when a clear physical<br>meaning must be established for the Elastic Impedance<br>(EI) as a real rock point property since it is, in fact,<br>only an approximation of reality. This is specially<br>striking for EI logs generation and very different approaches<br>can be found in the literature for this purpose.<br>In fact, the accuracy of the EI log generation may be<br>critical for a well based far–offset inversion process<br>since it must be applied for: a) feasibility analysis, b)<br>wavelet extraction c) low frequency constraint.<br>In this context, the main goal of this work has been to<br>carefully analyze some fundamental aspects related to<br>the EI log generation process, focusing the main three<br>applications described above. The discussion involves<br>both theoretical arguments, as practical examples obtained<br>from synthetic data, and real well log data sets.