--> 3D Structural Restoration Approach for Fracture Prediction — A Case Study from Kingdom of Saudi Arabia, Shokair, Khalid M.; Plesch, Andreas; Shaw, John, #90100 (2009)

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3D Structural Restoration Approach for Fracture Prediction — A Case Study from Kingdom of Saudi Arabia

Shokair, Khalid M.1
 Plesch, Andreas1
 Shaw, John1

1Exploration Resource Assessment, Saudi Aramco, Dhahran, Saudi Arabia.

The Tuwaiq-Mountain Formation represents one of the richest source rocks of Jurassic petroleum system in the
Kingdom of Saudi Arabia. Lithostratigraphycally, the section comprises relatively deep marine fine-grained, organic-rich limestones. Recently, a vertical exploration well programmed to test a deep Permian-Carboniferous gas target in downthrown fault block of the western forelimb of a gas field south of Ghawar field. Unexpectedly, a strong oil flow was encountered from the Tuwaiq-Mountain Formation which was unanticipated for the south Ghawar Area. Vertical cores and borehole images revealed poor, tight reservoir properties and the interpreted fractures were attributed to drilling induced fractures. In contrast, an openhole drillstem test indicated an excellent reservoir behavior in terms of permeabilities and recharge. Subsequently, the well location was investigated by full geomechanical 3D restoration approach relative to its structural position in the field. The new restoration technique indicated that large, dilatational strains had accumulated in the west flank of the structure where the well was drilled. This new strain information was integrated with seismic coherency to map the fracture zones in this region and their contribution to the oil flow from the tight reservoir. Also, the new understanding of the fracture system and its relation to the fold allowed sweet spots prediction for future exploration and delineation programs in the west of study area. This new unconventional play is opening potential oil exploration opportunities in the flanks of asymmetrical major folds in the Kingdom of Saudi Arabia.

AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil