Multi-scale analysis of well-logging data in petrophysical and stratigraphic correlation

摘要

Establishment of sequence limits in a stratigraphic column (i.e., related to depositional environments) represents in particular a great contribution to the analysis and characterization of oil reservoirs. In this context, we applied the continuous as well as the discrete wavelet transforms, to data from geophysical well logs from an oil producing area in the Gulf of Mexico, in order to bring about periodicities or cycles and correlate them with lithologic and stratigraphic characteristics of the associated environments.rnA multiscale analysis of geophysical well loggings (gamma ray, resistivity, and spontaneous potential) was done based in the wavelet transform. In particular the wavelet coefficients were determined. Analysis of the obtained spectrograms-scalograms enabled to establish characteristic pseudowavelengths for each scale (frequencies). Pseudo wavelengths were associated with possible periodicities in deposition (Milankovitch's climatic cycles) of the study area.rnThis case history shows that the wavelet analysis is a helpful complementary technique for reservoir characterization, specifically in the location of stratigraphic sequences and associated facies.