Oil and Gas
Resources of the North African Trias/Ghadames Petroleum Province
Lunn, Bob1, Allan F. Driggs2,
Patrick Thompson2, Philip Farfan1, Patrick Thompson2,
Francois Gauthier3 (1) Anadarko Petroleum Corporation and Anadarko
Algeria Corporation, Houston, TX (2) Anadarko Petroleum Corporation, Houston,
TX (3) Worldwide Business Development Group, Houston, TX
Anadarko and its Joint Venture partners,
ENI and Maersk, have been active for over 15 years in the Ghadames Basin. This evaluation
applied the methodology developed by Arps & Roberts on public domain and
company data. It predicts that the Paleozoic sourced – Triassic reservoir
petroleum system in the Ghadames Basin has less than 1 billion
barrels of oil reserves yet to be discovered. This represents less than
twenty-five percent of the potential identified by the USGS's world assessment
in 2000. It also predicts that all of those reserves will be distributed in
fields with reserves of less than two hundred million barrels. The Paleozoic
sourced – Triassic reservoir petroleum system of the Ghadames Basin of North
Africa, extends from eastern Algeria, (where its SW
extension has been renamed Berkine Basin), southern Tunisia and into western Libya. Oil and gas in
Triassic reservoirs have been correlated through the analyses of geochemical
markers to Silurian and Devonian mudstones. Migration from the Paleozoic
subcrop, uplifted by the Hercynian Orogeny, into overlying Triassic reservoirs
was direct and very efficient but; there is also evidence for migration
vertically up faults and long distances along Devonian and Silurian sandstone
carrier beds. The two source rock intervals had a very similar thermal history,
except that the Silurian section is more thermally mature because it is between
1000-2500 meters deeper. During the Hercynian, there was a major hiatus in
maturation of the Paleozoic interval and any earlier traps are assumed to have
been breached. The next phase of expulsion spanned the Tertiary.