Abstract
Bahrain Island is surface expression of a large anticline at depth - the Awali Field. It is one of the oldest producing fields, since 1932, in Middle East. Known producing reservoirs are in Cretaceous and Jurassic. In 1980s, E & P companies in Middle East started looking further below known reservoirs and there was regional success in Paleozoic Unayzah and Khuff Formations, which opened up new exploration frontiers in deeper gas. By late 1980s recognition of Paleozoic petroleum system started in Middle East. Discoveries made in Devonian reservoirs in Bahrain, Saudi Arabia & Turkey; Ordovician reservoirs in Jordan, Carboniferous reservoirs in Syria, and Silurian & Ordovician reservoirs in Iraq.
Authors attempted examining and assessing 325 Sq Km of 3D seismic and 400 line km of 2D seismic data, with six deep wells. Considerable Paleozoic section is deposited at Awali field and the anticlinal structure continues well into it, thus forming a basis for exploring an entrapment potential as deep gas play. Horizons interpreted below, producing Khuff and Unayzah, have numerous potential structures and their associated reservoirs in Jubah, Jauf, Tawil, Ra'an, Hanadir and Saq formations. The potential source rocks, such as Qusaiba Shales, also lie within Paleozoic section. Jauf reservoir of Devonian age is found to be gas bearing, and it needs appraisal and development. Fault Trap play anticipated for Jauf and below reservoirs. Its analogue has proven successful on the flanks of Ghawar structure in Saudi Arabia. Seismic data interpretation suggests some stratigraphic truncations, in lower parts of Paleozoic section and on the flanks of its structure, which in turn create a stratigraphic play. Considering high potential of hydrocarbon accumulation in Paleozoic, further exploration efforts are needed and authors initially propose new seismic acquisition campaign specially designed for imaging deeper plays in Awali.
