Sequence Stratigraphy Applied to a Continental Clastic Reservoir in a Low Aggradation Setting: The TAGI of Algeria & Tunisia

By

Chris G. Howells¹, Neil Mountford², Alan J. Scott³, Nick Lee²

(1) Anadarko Algeria Company LLC, Uxbridge, United Kingdom (2) Anadarko Algeria Company LLC, (3) Alan J. Scott and Associates, Boulder, CO

 The Trias Argileux Greseux Inferieur (TAGI) of Algeria & Tunisia has proven to be a highly successful hydrocarbon play in North Africa in the last couple of decades of the 20th Century. The reservoirs are clastic and predominantly continental in origin. However, the geographical extent of the reservoir system is truly continental in terms of scale and variations are observed.

Several workers have applied sequence stratigraphic principles to the Triassic interval of Algeria & Tunisia. Much of this work has been based on a sparse regional dataset and at various scales, varying temporally from the Triassic as a whole to just the reservoir interval, and varying spatially from the sub-regional exploration-scale to field development-scale.

Anadarko, in association with Sonatrach and various foreign partners in the region, has acquired a significant basin-scale database. The database includes over 8 km of core (mostly continuous over the reservoir interval), more than 80 wells with image logs, access to more than 200 wireline datasets in the region and production history/test data of several sizeable fields.

This presentation aims to demonstrate the applicability of sequence stratigraphic principles (the relative roles of eustacy, climate and tectonics) at various scales (temporal and spatial) to key business issues (exploration and development) in this important North African reservoir system.