Albertine Graben Blocks

Location

The Albertine Graben, with an area of approximately 22,000 km² in the Congolese part of the Basin (~14,000 km2 for the Lake Albert Basin and ~8,000 km² for the Lake Edward Basin), is part of the West Branch Basins of the East African Rift and is located between 1°26' and 2°30' South latitude and between 29°00' and 31°31' East longitude, east of the Democratic Republic of Congo.

Geological & Structural Context

In the Albertine Graben, sediment fill was from the Mesozoic (Jurassic or Cretaceous) to the Quaternary. The formations, probably of continental origin, consist of sands, sandstones, conglomeratic sandstones, bituminous shales with alternating sandstone formations, indurated clays, green clays, breccias, conglomerates and lignites, all resting on the crystalline base.

The thickness of the sediments is ~6000m.

The Lake Albert-Semliki Trough is a graben aligned with a major lineament marked by several structural features, particularly carbonatite and kimberlite intrusions. The alkaline intrusions are dated to the Lower Cretaceous, suggesting the initial phase of Lower Cretaceous rifting.

South of the Lake Albert-Semliki Graben is the Lake Edward Graben. The two grabens are asymmetrical and separated by a large Precambrian basement block, Mount Ruwenzori, which culminates at 5,100 meters above sea level. The latter creates favourable conditions for setting up structural and stratigraphic traps, thus constituting exploration objectives.

Petroleum Systems of the Albertine Graben

The various exploration works carried out on both the Ugandan and Congolese sides further prove that the oil system has worked very well in the Albertine Graben.

Reservoir Rocks and Cap Rocks

• Middle and Upper Miocene sandstone (Kisegi sandstone)

• The fault formation of Garamba covered by the argillites of Waki

Source Rocks

• Bituminous shales: Waki formation

• Bituminous argillites and flubvio-lacustrine sandstone argillites

• Lacustrine sandstone argillites: Kaiso formation

Traps

• Structural traps

• Stratigraphic traps

• Tilted blocks

• Faulted blocks in flower structure

Main Plays

• Middle and Upper Miocene sandstone (Kisegi sandstone)

• The fault formation of Garamba covered by the argillites of Waki

The seismic and drilling work carried out in the blocks adjacent to blocks I and II of the Democratic Republic of Congo, highlighted the structures in flower recalling on a small scale a system of collapse made of Horsts and grabens and which suddenly constitute safe from structural pitfalls.

Since the Albertine Graben is deeper in the Democratic Republic of Congo, it is assumed that trapping structures of large dimensions could contain economically exploitable reserves.