Abstract: Exploring in the Shadow of a Super Giant, Hassi Messaoud, Algeria
BOND, VICTOR O,
DAVID
P JAMES, PAUL D JACKSON, and SAID CHELBI,
The Cambrian Ri, Ra and R2 sandstones of Central Algeria are represented by a thick sequence of transgressive marine and fluvial deposits. These sandstones are significant oil producers with large reserves at Rhourde el Baguel, Mesdar the El Gassi Field trend and the Super Giant Hassi Messaoud Pool. Proximal to Wascana's Block 427, which is located in the shadow of Hassi Messaoud, the coarse grained sandstones of the Ra are composed of numerous fining-upwards successions of braided stream origins. The medium to coarse grained sandstones of the overlying Ri are characterized by flat-beds, less abundant cross-bedding and heavy bioturbation by skolithos, features indicating a marine depositional setting.
While the Ri and Ra sandstones are the main producing intervals, most Cambrian pools differ in structural history. Oil Staining is obvious in cores from Hassi Messaoud, whereas in the other Cambrian fields, oil staining is very light or absent. This observation and other data suggest two stages of oil migration into the area, with the first accumulation being biodegraded. Vastly improved seismic resolution at the Cambrian level has resulted in better imaging of subtle pre-Hercynian aged structures. This observation and the recent exploration activity in the area suggest that additional pools analogous to Hassi Messaoud are likely to be discovered.
AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria