Discovering and Developing a Deep Jurassic Play in the Mature Western Desert, Abu Gharadig Basin, Egypt

摘要

The Abu Gharadig Basin in the Western Desert (NW Egypt) is a mature hydrocarbon province with over 95% of the oil and gas fields in the Upper Cretaceous Abu Roash, Bahariyah and Kharita sandstone reservoirs. Many wells had penetrated the thick Lower Cretaceous Alam el Bueib sandstone reservoir but no significant discoveries were made. This led most operators to believe that there was very little prospectivity at deeper levels, in particular in the Jurassic Safa sandstones overlying the Palaeozoic basement. Shell acquired the North-East Abu Gharadig (NEAG) Basin Exploration License of almost 10,000 km km2 in 1996 with parts covering a proven structural trend with several Upper Cretaceous opportunities. Information of existing wells in the concession also indicated the presence of Jurassic reservoir/seal pairs underpinned by oil shows. After a disappointing initial exploration campaign focusing on Cretaceous targets, Shell shifted focus to the Jurassic play. In 2002, the JG-1 exploration well found 6 m of light oil pay in Lower Safa sands at 3,200 m depth and proved commercial flow rates. Five additional appraisal/development wells and 3D seismic have outlined an oil-rim field in a fault-bounded, compartmentalised, dip-closure with significant lateral variation in reservoir quality/distribution. The field is currently producing at rates of 30 MMscf/d and 5,000 bbl/d under primary gas cap expansion drive. Based on the commercial success of the JG discovery further exploration activity in the Abu Gharadig Basin continues to focus on the Jurassic play which has larger volume potential than the traditional Upper Cretaceous plays. The presentation will cover the exploration strategy, the discovery and early development of the JG field and the JG field development plan. The story of the NEAG concession demonstrates that lucrative opportunities in mature basins remain if comprehensive data analysis is combined with creative thinking and perseverance.