Multi-Scale Analysis of Gamma Ray and Resistivity Logs as a New Approach for Early Flow Units Identification

Abstract

After drilling a well, early flow unit characterization might be very useful for further reservoir developments. Up to now, most of the methods suggested for flow unit identification are based on using core data. In the proposed approach in this study, core data are again considered as the basis but extending the flow units to other wells are done using gamma ray and resistivity logs that are interpreted in a new way. Using core data, normalized cumulative flow zone index (NCFZI) is calculated for each data point. Studying this parameter in the time-scale space of wavelet reveals exact numbers of the flow units along the depth. Wavelet transformation and reconstruction of gamma ray signal shows that this log type exhibits the locations of flow units changes very well, therefore can be used in uncored wells for early characterization. To determine the quality of each flow unit, wavelet transform of resistivity logs that are found capable of indicating high-permeability zones are utilized separately for each flow unit. High-frequency signals of resistivity logs correspond to each unit are an indication of high potential of that unit to fluid flow.