Petroleum System Modeling of the Rovuma Delta Basin, Mozambique

Keith Mahon, Van Mount, Carol Law, Tom Fletcher, and Thad Dunbar
Anadarko Petroleum, The Woodlands, TX

The Rovuma basin of northern Mozambique is one of the few largely unexplored Tertiary deltas that exist in the world. The delta’s potential for substantial hydrocarbon accumulations is based on the existence of numerous independent play types.

The Rovuma delta is a classic example of a linked extensional-contractional system. Late Miocene-to-present day deformation is interpreted to be in response to updip sediment loading and regional tilting, above a master detachment in Early Oligocene/Paleocene age strata. A 240km transect across the entire linked system was constructed and restored for petroleum system modeling.

Restored sections from late Miocene-to-present provide input geometries for PetroMod 2D. The model includes source horizons from Triassic to Paleocene, reservoir horizons within the Oligocene and Miocene, and sealing shales within the Neogene section. Sensitivity runs are made using variations in heat flow and source rock richness. In addition, results of hybrid petroleum migration (Darcy flow + flowpath) and invasion percolation (capillary flow) are compared.

The results suggest that mixed oil and gas accumulations are likely in the deepwater compressional blocks. Additional potential is seen for multiple stacked pays in the Oligo-Miocene section of the extensional regime. Results also illustrate the onset of late Miocene deformation may be coupled with the initial hydrocarbon generation in Paleocene sources. Increased pore pressure resulting from hydrocarbon generation may have contributed to the formation of the master detachment. An aggressive exploration program has been designed to test the petroleum system of the Rovuma basin.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas