New insights on interpretation of seismic attributes in Nile-Delta basins for analyzing Pliocene geological characteristics

Abstract

Northern parts of Nile Delta is largely unexplored because of variety of constraints and other exploration priorities. Exploration and production (E & D) in these areas are challenging tasks,where water depth reaches 1000 m sec on the seismic scale. This complicates application of seismic reflection technology, even affecting the assessment of economic value of assets, if any existing at these depths. Several DHI anomalies that have been reported in the seismic data are neither earlier documented nor interpreted systematically in corroboration with the existing exploration data in the Nile Delta region. The exploration activity in the offshore and onshore Nile Delta is largely based on adaptation of conventional bright-spot DHI technique and analysis of DHI anomalies. Number of seismic vintages and drilled well data are considered in the current research and integration analysis. Existing wells, drilled at Pliocene level areanalyzed to understand the structural and reservoir characteristics of the successful cases, based on DHI anomalies. The outline of the analysis is based on similarity and dissimilarity of properties of the DHI anomalies. These properties are interpreted in alignment with geologically and seismically connected disparities, more specifically based on sedimentological and geophysical characteristics of the sand bodies. The dissimilarities interpreted, are carefully analyzed corroborating with drillable successful cases. These corroborations validate the prevailing successful wells as well.The interpretation and analysis are based on the DHI anomalies and their associated properties that varying laterally and vertically on the seismic data. These anomalies are validated from the known subsurface drilled well data. Relationships and connectivity among DHI anomalies from known and unknown are recognized. These wells are primarily distributed between western and eastern sub-basins of the Nile Delta. In spite of the limitations of the existing technique and other exploration constraints, risk of big accumulations is lowered and success rates are enhanced by DHI techniques. In addition, a distinct variation is distinguished between expected and current producing reservoirs in the Nile Delta Basin. This study can facilitate the explorers prioritize their areas for investment.