Sedimentology, Biostratigraphy, and High Resolution Sequence Stratigraphy of the Middle Jurassic - Shams Field, Western Desert, Egypt

By

Marty R Smithey¹, Tarek Saad¹, John Youle¹, Guy Oliver², Carl Watkins², Marguerite Fleming², Jim Fenton²

(1) Apache Egypt Corporation, New Maadi - Cairo, Egypt (2) Robertson Research International, North Wales, United Kingdom

 The Middle Jurassic section along the Khalda Ridge is complex and discontinuous consisting of eight to ten multi-story stacked reservoir units totaling more than 2000' in thickness. At present, the sand bodies are difficult to correlate and predict away from the borehole. A detailed high resolution sequence stratigraphic reservoir study of the Shams Field has been conducted to enhance our understanding of sand body connectivity, architecture and, geometry away from the borehole.

The Shams Field has calculated proven Jurassic reserves of more than 450BCF and is one of the largest gas and condensate fields in the Western Desert. Since successfully deepening Shams 1 to the Jurassic in 1990, 8 wells have penetrated the Jurassic section. 6 of these wells are currently producing almost 100mmcf/d and 1500 bcpd from the Jurassic reservoirs.

A total of 562 feet of core has been described at a 1:200 scale focusing on the identification of candidate stratal surfaces and facies analysis necessary for sequence stratigraphic framework construction and complex depositional modeling. Targeted biostratigraphic sampling, incorporating palynology and micropaleontology was undertaken to help categorize and confirm candidate stratal surfaces and depositional systems.

All results have been integrated in order to develop a "new" Jurassic high resolution sequence stratigraphic framework. Identification and prediction of major sequence stratigraphic stratal packages within this framework is important because sand body orientation, distribution and reservoir architecture will be unique within each, thus allowing for more valid reservoir characterization, realistic volumetric calculations and, accurate future well planning.