A Sedimentlogical & Integrated Case Study Towards More Understanding Of The Depositional Regimes In Complex Structures

Abstract

Abstract This study discusses the depositional setting of the Upper Cretaceous clastic dominated Abu Roash G reservoirs of Cenomanian age which deposited during in an overall transgressive setting continued into the Turonian and reached culmination in the deposition of the overlying Abu Roash F limestone as a clear regional marker. Abu Roash G is divided into two main units, Upper & Lower Abu Roash G separated by the transgressive surface represented by the Intra Abu Roash G limestone which is easily to be tracked allover Abu Gharadig basin. Each of the Upper or the Lower Abu Roash G units has more than one sand reservoir unit. This study tries to construct a paleogeographic model for each of the sand units of Abu Roash G in Alam El Shawish area. The interpretation was derived from wireline logs, Image, seismic attributes, depositional regimes & the experience absorbed from the nearby areas in Abu Gharadig basin using calibrated correlation / sequence stratigraphic framework through detailed core based facies. The sea level oscillation had a profound influence on sedimentation of Abu Roash"G" Member in Alam El Shawish area. Abu Roash "G" Sandstone reservoir provide a good case history for coastal setting & believed to be exhibit both regressive and transgressive trends. This is related in lateral changes in distribution of sandstone from tidal channel, tidal flat, and barrier bar to tidal bar cross Alam El Shawish fields & vertical change through the time. According to the integrated vision of the geological & seismic data that always add value to any prospect, field, or basin, seismic attributes computed from the 3D seismic data set proved useful in relating different reservoir characteristics interpreted from well data. These attributes were merged into the geological models & provided a description of the porosity distribution in Bahga field.