Integrated petrophysical and geological characterization for the Sidi Salem-Wakar sandstones, off-shore Nile Delta, Egypt

The present work provides a preliminary study to clarify the geological setting and petrophysical potential of the offshore Temsah gas field, which is located as a NW-SE trending anticlinal structure. In the Temsah gas field, the main target is the Serravallian Sidi Salem sandstones while the second target is the Tortonian Wakar Formation. The Sidi Salem Formation produces gas and condensates from three main sand lobes, while Wakar Formation produces from some sand interbeds. The seismic velocity in Temsah gas field was a major problem due to the complexity of the structural and stratigraphic setting, and the existence of a strong pattern of multiples generated by the Rosetta evaporites at the top of the Miocene sequence. In the present study, an integrated interpretation was applied for the available well logs and the subsurface geological data as well as some available seismic sections. The highest hydrocarbon potential in the Sidi Salem sand lobes has been assigned for sand lobe III, which has the largest net pay thickness and the best petrophysical properties, particularly in the southern to the northern central wells across the crest of the structure. The basin depocenter extends along the central parts through Temsah-1, -2, -3 and -8 wells. The maximum average effective porosity values of the Sidi Salem reservoir were recorded in Temsah-5 and Temsah-1 wells (27% and 30%, respectively), to the northwestern and southeastern parts of the field at the crest of Temsah anticlinal structure, while the considerable porosity values of the Wakar reservoir were measured in the southern wells. Permeability of the Wakar reservoir increases with increasing porosity and decreases with increasing the water saturation, whereas for the Sidi Salem reservoir, permeability is dependent on porosity rather than the water saturation. The minimum average water saturation values for Sidi Salem and Wakar reservoirs were recorded in the central parts of the field (25% and 30%). The shale volume in both reservoirs is not effective (smaller than 13%). In general, the net oil column of Sidi Salem reservoir wells indicates a better reservoir quality for Temsah-1, Temsah-3, and Temsah-7 wells (the net pay varies in thickness from 48 to 69 m) at the crest of Temsah anticlinal structure to the north and central west of the field; while for Wakar reservoir it indicates a better quality in Temsah-3 well (9.0 m) to the north of the field. (C) 2015 Elsevier Ltd. All rights reserved.