Geological and Petrophysical Studies of the Bahariya Formation, Heba -100 Oil Field, Western Desert, Egypt.

Abstract

The present study deals with the Cenomanian Bahariya Formation in the Western Desert, characterizing Upper Member of Bahariya Formation as it is one of the most important reservoirs in Egypt. The study area located at the north Western Desert, East Abu Gharadig basin, between Latitude 29⁰ 35ʼ 2.4ʼʼ N and 29⁰ 33ʼ 36ʼʼ N and between Longitude 29⁰ 48ʼ 28.8ʼʼ E and 29⁰ 50ʼ 52.8ʼʼ E. The main objective of this study is to investigate subsurface and reservoir characteristics to evaluate hydrocarbon potentialities of Upper Member of Bahariya Formation. Subsurface stratigraphic column of Heba-100 oilfield ranges in age from Upper Creataceous Bahariya Formation to Eocene Apollonia Formation. The study area shows a NE trend asymmetrical fold dissected by NE normal fault and structural highs and lows anomalies, separated by fault polygons. In the present study, a correlation is constructed between the studied four wells of Heba-100 oilfield to represent the lateral facies change and thickness variation. The Upper Member of Bahariya Formation is classified into seven zones named from top to bottom: (UB 1, UB 2, UB 3, UB 4, UB 5, UB 6 and UB 7). From the constructed correlation chart and isopach maps of Upper part of Bahariya Formation, there is no big difference in thickness between wells which indicate that Upper Member of Bahariya Formation has been deposited at stable tectonic environment so, the sedimentation is approximately equal along the wells, based on stratigraphic interpretation. According to ditch cutting lithology description, it is concluded that the depositional environment of the study area is shallow marine environment, where the percentage of sandstone ranges from 44.80 % to 55.37%, Siltstone ranges from 23.14% to 41.10%, Shale ranges from 5.85% to 19.92%, and Limestone ranges from 1.98% to 8.18%.