High resolution sequence cyclostratigraphic modeling of Albian – Cenomanian succession based on statistical, time series and palynofacies analyses in Meleiha Basin in the Western Desert, Egypt

The Albian-Cenomanian succession in the Western Desert of Egypt represents important source/reservoir rocks. This succession comprises the Kharita and Bahariya formations in addition to the G Member of the Abu Roash Formation. These rock units were studied here using extensive sequence stratigraphic modeling. This model was based on high resolution statistical and time series analyses of electric logs from three well sections in the Meleiha Basin. This is a novel approach in this type of studies in this region. These well sections are the Safir N-2X, Hayat-4X, and Tut-1X arranged from south to the north direction in the study area. The statistical investigation included constrained single linkage and principal component analyses of characteristic lithological electric logs. The time series analysis was conducted using continuous wavelet transform (CWT), Morlet wave transform, and evaluative short-wave Fourier transform. Sixteen (16) short term sequences and 4 long term sequences were identified in the studied well sections and they were correlated with the global sea level curve. This is the highest resolution model identified in this area to the date. The time series analysis provided a cyclicity ratio that was used in the astronomical tuning of the identified sequences to the orbital time scale. Additional Fisher plots and palynofacies analyses were carried out to explore the paleoenvironmental settings. The Fisher plots revealed changes in the accommodation size that is in accordance with long term stratigraphic changes. The accommodation space increased significantly up-section in the Bahariya Formation and Abu Roash G Member. The application of statistical classification of palynofacies by cluster and correspondence analyses led to the identification of three palynofacies types (palynofacies type A, B and C) and proximal-distal trend that was determined by the correspondence values. The depth stacking of palynofacies and proximal –distal trend were attributed to long term stratigraphic changes and correlate well to the accommodation calculated from the Fisher plots. The integrated sequence stratigraphic modeling accomplished in the present study increases our understanding of the source/reservoir distribution in the Albian Cenomanian succession and will be of great benefit for current and future exploration plans in the Meleiha basin. In addition, the approach used in this study provides sequence boundaries and maximum flooding surfaces that could be