--> Abstract: Stochastic Modeling of the Wafra Maastrichtian Reservoir, Partitioned Neutral Zone (Saudi Arabia and Kuwait); #90063 (2007)

Datapages, Inc.Print this page

Stochastic Modeling of the Wafra Maastrichtian Reservoir, Partitioned Neutral Zone (Saudi Arabia and Kuwait)

 

Meddaugh, W. Scott1, Raymond A. Garber1, Stewart Griest2, Dennis W. Dull1, Rebecca Latimer3, Arturo Contreras1 (1) Chevron Energy Technology Company, Houston, TX (2) Chevron Energy Technology Company, Houston (3) Chevron, Houston, TX

 

The Maastrichtian reservoir is one of five prolific oil reservoirs in the giant Wafra oil field. Maastrichtian oil production is from subtidal dolomites that average 15% porosity and 30 md permeability though porosity values up to 40% and permeability values over 1000 md are common. Discovered in 1959, the Maastrichtian reservoir has produced less than 1% of its 1.5 billion barrels of low API, high sulfur oil in large part due to reservoir heterogeneity.

 

The carbonates were deposited on a very gently dipping, shallow, and restricted ramp setting that transitioned between normal marine conditions and restricted lagoonal environments. The Maastrichtian interval is part of the Aruma Group (Tayarat Formation) and is divided into an upper and lower portion by the Second Maestrichtian shale. The lower interval consists largely of peloidal mud-lean dolopackstones and minor grainstones were deposited under humid conditions during a transgressive phase that evolved into a high stand. The upper portion consists of dolorudstones and dolofloatstones alternating with peloid-rich, fine-grained dolostones that grade upward into argillaceous dolowackstones and dolopackstones deposited during a relative high-stand under arid conditions. Ten high frequency sequences have been correlated across the field.

 

A detailed geostatistical model of the reservoir constrained by the sequence stratigraphic interpretation and stochastic seismic inversion shows the layered and compartmentalized nature of the reservoir and demonstrates that paleotopography had a critical influence on depositional facies and subsequent dolomitization. Analysis of FMI and production data enabled a fracture characterization to be incorporated in the dynamic model of the reservoir.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California