The Hydrocarbon Potential of Deep-Water Offshore Algeria

Cope, Michael J., WesternGeco, Gatwick, United Kingdom

The deep-water margin of Algeria is an unexplored frontier. Previous drilling has been limited to a single deep exploration well and one DSDP site. Understanding and further exploration of the area has previously been hindered by the lack of seismic resolution beneath a thick Messinian salt layer.

A newly available seismic survey has revealed the presence of significant areas of pre-Messinian rift basins below the regional salt layer. The development of critical elements for active petroleum systems can be recognized at various stratigraphic levels:

1. Pliocene cover sequence – secondary reservoir and biogenic source potential.

2. Messinian Salt – regional seal.

3. Miocene rift basin fill – primary reservoir and source potential.

4. Basal complex (Tellian allochthon and/or Hercynian Basement) – secondary reservoir and source potential.

Potential trapping geometries include tilted fault blocks within the basal complex, drape anticlines and stratigraphic pinch-outs within the Miocene and salt-supported anticlines in the Pliocene.

A pattern of seismic amplitude anomalies associated with many of these potential traps points to the presence of effective petroleum systems and hydrocarbon charge mechanisms to be operative along the Algerian deep-water margin.