Angola:
A SPOT satellite interpretation of the Kwanza and Kabinda Basins.
Client:
Non-exclusive
study purchased by various major oil companies.
Location:
Angola
- Kabinda and Kwanza Basins
Terrain and Climate:
Coastal:
undulating and cultivated
Inland: Mountainous (Precambrian Basement)
High rainfall, frequent and continuing cloud cover, especially northwards
becoming equatorial.
Area - km2:
Kwanza:
69,000 km2 , Kabinda: 25,200 km2
Objectives:
Regional:
Better understanding of basin structure and evolution.
Identification of transfer zones and their relationship
to basin compartmentalisation.
Identify reactivated basement structures
Detailed:
Assess the effect of ‘Raft tectonism’ in the
development of the basin.
Identification of salt diapirs and salt walls.
Geology and Prospectivity:
Kwanza:
Extreme extension (Raft tectonics) of Upper Cretaceous
and Tertiary units along Aptian evaporites. Hydrocarbons
occur in all of the post-salt units, major deposit in Oligocene-Miocene
troughs - eg. Quenguela.
Kabinda:
Prospects mainly in pre-salt section - salt acts as an
effective seal.
Data available for integration:
NPA’s Tectosat Africa and W.Africa offshore studies.
Kwanza only, at 1:500,000 scale.
Regional mosaics of SPOT scenes (19 Kwanza, 7 Kabinda)
enabled identification of major controlling transfer zones.
Integration of gravity and magnetic data to identify subsurface
volcanic features and to assess their affect on the overlying
extending section.
Kabinda - combination of P + XS scenes at 1:100,000 scale.
Kwanza - 19 SPOT XS scenes at 1:100,000 scale.
Overlays to individual images at 1:100,000.
Composite maps at 1:200,000 and 1:500,000 scales.
True scale schematic cross-sections.
Benefits and Results:
Provides an excellent introduction to the complex geology
of the region (combined with NPA’s West Africa report).
Identified structural zonation of the Kwanza basin, thus
aiding in the understanding of the structural evolution of
the basin.
Assessed the hydrocarbon potential of the basin in relation
to hydrocarbon migration and possible traps.
Located major structural closures and assessed these in
relation to those previously drilled. 50% more identified
features than previously explored
Onshore structural pattern and understanding can be extrapolated
into the offshore to help with seismic interpretation.
Innovation:
This
area, particularly the Kabinda enclave, is out of range of
Landsat receiving stations so no suitable cloud-free TM imagery
exists. The SPOT satellite was programmed, with advice from
NPA, enabling the acquisition of virtually cloud free images.
Cost:
Imagery
and interpretation $1.8 per sq.km.
Future Developments:
A
new project is now underway to map regional palaeo-drainage
patterns and onshore sediment sources as a means of predicting
offshore sedimentary provenance, which will be further investigated
using special processing of satellite gravity. The results
will be related to offshore seepage mapped with satellite radar.
