Abstract
Oil Fields in the offshore Zaire (D. R. Congo) area are located in the Congo basin. This basin was developed as a result of South Atlantic rift that was initiated towards the end of the Jurassic period. The sedimentary section in this area is divided by the Aptian salt into a presalt nonmarine sequence and a postsalt marine sequence.
The structural style of the Pinda formation (postsalt) is characterized by salt movement and associated with growth faults. Salt movement at the early stage of the Pinda deposition developed many down-to-basin normal faults. While significant salt diapirs raised and Lower Pinda formation slipped toward the basin and leaned eastward Upper Pinda carbonate deposited. The salt movement and stratigraphic expansion were terminated during the deposition of Kinkashi formation (Early Cenomanian). As a result of this salt tectonics, the Lower Pinda formation was separated into several fault blocks by down-to-basin listric faults. Those fault blocks are similar to “rafts” that were recognized in the Cuanza Basin (Duval and Cramez, 1992; Jackson and Talbot, 1991; Jackson, 1997). The stratigraphic expansion is calculated approximately as 1 to 1.3km/million years. However, at the early stage of the Upper Pinda carbonate deposition, significant salt deformation occurred, which is calculated to be on the order of approximately 3km per million years.
Carbonate and sandstone rocks of the Pinda formation serve as the main reservoir. The salt diapirs controlled the distribution of sandstone and the reservoir quality of carbonates.
