Sandstone-Body Geometry, Facies Architecture and Depositional Model of Ordovician Barik Sandstone, Oman

Iftikhar A. Abbasi and Abdulrahman Al-Harthy*
Sultan Qaboos University, Oman
*[email protected]

The Lower Paleozoic siliciclastics sediments of the Haima Supergroup in the Al-Haushi-Huqf area of central Oman are subdivided into a number of formations and members based on lithological characteristics of various rock sequences. One of the distinct sandstone sequences, the Barik Sandstone (Late Cambrian-Early Ordovician) of the Andam Formation is a major deep gas reservoir in central Oman. The sandstone bodies are the prospective reservoir rocks, whereas thick shale and clay inter-beds act as effective seals. Parts of the Barik Sandstone, especially the lower and middle parts, are exposed in isolated outcrops in the Al-Haushi-Huqf area as inter-bedded, multi-storied sandstone, and green and red shale. The sandstone bodies are generally up to 2.0 m thick and can be traced laterally for a few hundred metres to a few kilometres. Most of the sandstone bodies show both lateral and vertical amalgamation. Two types of sandstone facies are identified on the basis of field relationship: (1) a white sandstone facies usually capping thick red and green shale beds; and (2) a brown cross-bedded sandstone facies overlying the white sandstone facies. An attempt was made to study the relationship of fluvial, fluvio-deltaic and tidal processes on the basis of lithofacies characteristics. This presentation summarizes the results of a preliminary study carried out in the Al-Haushi-Huqf area to analyze the characteristics of the sandstone-body geometry, internal architecture, provenance and diagenetic changes in the lower and middle parts of the member.

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain