From Neoproterozoic to Early Cenozoic: exploring the potential of older and deeper hydrocarbon plays across North Africa and the Middle East

Abstract

AbstractAs the traditional exploration plays in the main productive basins of North Africa and the Middle East become more ‘mature’, attention is increasingly focusing on more challenging, older and deeper plays in the main producing basins and on high-risk, but more conventional, plays in under-explored frontier areas. This shift brings with it a range of technical and commercial challenges that must be addressed, if exploration in the region is to remain an attractive proposition. Exploration in North Africa and the Middle East has traditionally focused on the prolific Mesozoic- and Cenozoic-sourced petroleum systems of the Nile Delta, the Sirte Basin, the Pelagian Shelf, and the Arabian Plate and on the Palaeozoic-sourced petroleum systems of the Berkine, Ghadames, Illizi, Ahnet and Murzuq basins, the Central Arabian Basin, the Qatar Arch and the Rub Al Khali Basin. Together these form one of the most prolific petroleum provinces in the world and, as a consequence, there has been little commercial incentive to invest in exploring more challenging and riskier plays in these areas. However, as the need to find new reserves becomes imperative, attempts are increasingly being made to test new play concepts and to extend already proven plays into new areas. Key recent developments in this regard include the recognition of the hydrocarbon potential of the Neoproterozoic to Early Cambrian (‘Infracambrian’) sedimentary section lying below the traditionally explored Palaeozoic succession in many basins in North Africa. In some areas, particularly the Berkine Basin in Algeria, the Nile Delta in Egypt and the Rub Al Khali Basin in Saudi Arabia, attention is also increasingly being focused on developing deeper gas plays, both in new areas and beneath existing producing fields. The technical challenges associated with these deeper gas plays are immense and include difficult seismic imaging of deep prospects, low porosity and permeability, high temperature and pressure and a critical need to identify ‘sweet spots’ where either locally preserved primary reservoir characteristics or secondary enhancement of reservoir quality through palaeo-weathering and/or fracturing allow commercial rates of gas production to be achieved. Despite these challenges, it is clear that the future for exploration in many of the more mature basins of North Africa and the Middle East will increasingly lie in evaluating such older and more deeply-buried plays.