Old Idea with New Application in Oman

László Csontos¹, Ágoston Sasvári², Tamás Pocsai³, Gizella Árgyelán¹, István Dunkl⁴, and László Fodor^5
1MOL PLC, Hungary, Budapest, Hungary
²MOl PLC, Hungary, Budapest, Hungary
³MOL PLC, Budapest, Budapest, Hungary
⁴Göttingen University, Göttingen, Germany
⁵Hungarian Geological Survey, Budapest, Hungary

Conventional plays in Oman are based on Infracambrian and Cretaceous source rocks, Cretaceous platform limestone reservoirs and Late Cretaceous marls of the Arabian platform as seals. Hawasina-MOL PLC acreage in Oman Mts contains oceanic sediments (Hawasina) and obducted ophiolites (Semail) above this platform. The Arabian platform with potential reservoirs is exposed in two antiformal windows. We hope to find these reservoirs in a third antiformal window covered by Hawasina nappes.
Inaugurating field work helped to revise the earlier map. The lowest nappe (Sumeini) is exposed in three antiforms. One antiform is prolonged in Hamrat Duru oceanic sediments. These structures might be underlain by positive structures of the Arabian platform.
Structural history begins with a first phase related to Cenomanian obduction. Formation of the original nappe stack was soon followed by a secondary nappe formation along particular detachments. This phase was followed by syn-cleavage folding and thrusting towards NE. A third phase transported part of the window northwards and a fourth event created SW-vergent shears, which might be synchronous with folding and SW-vergent thrusting during Miocene. Ongoing investigation on the metamorphic grade of the Hawasina units shows amphibolite soles adjacent to ophiolite contacts and widespread anchimetamorphism in oceanic sediments. This does not necessarily downgrade our prospects for two reasons: 1, metamorphism might be allochthonous above the less metamorphic Arabian platform; 2, Miocene displacements might have been important enough to bring non-metamorphosed sediments beneath the window.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece