Seismic data highlights: Mozambique

Added: 21st April 2020 by CGG

In collaboration with the Instituto Nacional de Petroleo (INP), CGG has recently delivered 15,400 km² of 3D final depth imaged seismic data over the Beira High in the Zambezi Delta, offshore Mozambique. The ultramodern survey is the first following the agreement CGG signed with INP to acquire up to 40,000 km² of 3D data.

CGG’s advanced imaging workflow, including Full Waveform Inversion (FWI), has revealed a high level of detail in this complex geological setting, such as the deep marine turbiditic system present in the area and the faulting pattern and internal architecture of the Beira High.

The data has allowed accurate identification of key stratigraphic intervals for a better understanding of the petroleum system and, in conjunction with high-resolution gravity and magnetic (gravmag) data, has brought new information on the basin morphology and its evolution.

The Zambezi Delta Basin is one of the oldest offshore basins in the East African margin, formed as a consequence of the breakup of eastern Gondwana. The image shows the present day complexity of the western Indian Ocean (red to blue represents oceanic crust of increasing age and purple continental sediments) and its modelled configuration 145 & 160 million years ago with the location of the survey area shown by the black star.

The survey area’s crustal nature and the distribution of sediments across the basin was inferred from analysis of the gravmag data in conjunction with the seismic image. The Bouguer gravity map in the image below (4a) shows a gravity low over the Beira High, a north-east to south-west elongated structural feature located offshore that extends for more than 150 km.

The magnetic anomaly map (4c) differentiates a northern domain, which is relatively quiet magnetically, from a southern domain characterised by two distinct magnetic anomaly orientations associated with the Beira High. One is observed over its northern flank, and the other, a set of north-west to south-east anomalies, within its internal architecture. The interpretation of the seismic data and how it links with both maps is shown in 4b. Note the figures have been extracted from the CGG article Hydrocarbon Potential of the Zambezi Delta Basin, Mozambique in GeoExPro.