Reservoir Presence in the Albian Carbonates (Madiela Formation) Offshore Gabon

Louzada, Carlos ¹; Braun, Christian ¹
(1) Addax Petroleum, Geneva, Switzerland.

The Albian carbonates offshore Gabon (Madiela Formation), which are an equivalent to the highly productive Pinda formation in the Lower Congo Basin in Angola, have been targeted for hydrocarbon exploration in offshore Gabon for many years with little success. In the South Gabon basin, several exploration wells drilled in the late Albian carbonate formations have encountered good quality reservoirs. This poster presents a case study with the objective of understanding the reservoir distribution in these carbonates based on well and seismic data.

From well logs and lithology descriptions three main environments of deposition were identified showing distinctive geologic trends: lagoon, restricted to open shallow marine and slope.

From cross plot observations, there appears to be a relationship between well log acoustic impedance and the environments of deposition, which are thought to be a direct response of lithology and porosity. Ongoing seismic attribute studies may help to define trends that could then be matched to the geologic depositional environments.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.