«Geology, geophysics and development of oil and gas fields»

The principal gas bearing basin of the south-east African continental margin

UDC: 553.98(679+678+676.2)
DOI: 10.33285/2413-5011-2023-4(376)-23-26

Authors:

¹ P.P. Shirshov Institute of Oceanology Russian Academy of Sciences, Moscow, Russia

Keywords: continental margin, gas, oil, basin, field, hydrocarbons, deep-water region

Annotation:

At present the South-East African continental margin is in the active process of prospecting and exploration works. However, unlike the West–African continental margin, where for a long time throughout its entire length mainly liquid hydrocarbons were discovered, in the region under study only gas accumulation is known mainly in Rovuma basin. Rovuma basin is situated in the north-east of Mozambique, being a part of the wide south-eastern part of the African frontier basin, which also includes the parts of littoral plains and continental margins in the south-eastern part of Tanzania and Kenia. The basin is characterized as a passive continental margin with a complex tectonic history. Only in 2010 due to the discoveries of numerous large gas fields in the north-eastern part of Mozambique and in the south-eastern part of Tanzania, in the deepwater regions of the Indian ocean in the Rovuma basin, Mozambique gained a new status – a big hydrocarbon player in the World, and the Rovuma basin – a principal gas bearing basin in the region. The analysis more of 20 gas fields that have been discovered in Mozambique lately, it is revealed that all of them are located in the deep-water regions, that is at the continental slope. As well as they are located at different depth – from 468 to 2610 m on the offshore of the Indian ocean. It is also noteworthy, that the single-age deposits, the deeper they are buried under the water column the more is their hydrocarbon reserves volume. The similar trend can help in case of targeted exploration for oil and gas. At present, along the whole territory of the Rovuma basin large-scale prospecting and exploration works are being underway, ensuring the discovery of numerous gas fields.

Bibliography:

1. Brownfield M.E. Assessment of undiscovered oil and gas resources of the Mozambique coastal province, East Africa // US Geological survey. – Reston, Virginia, 2016. – 12 p.

2. Cameron N., Rego M. Underexplored African source rocks // Exploration Africa. – 2020. – Vol. 17. – № 5. – P. 24.

3. Development plan decided for offshore Mozambique // Oil and Gas Journal. – 2015. – Vol. 113. – Pp. 9–10.

4. Petroleum systems of the deepwater Mozambique basin / M. Francis, G. Milne, K. Kornpihl [et al.] // Energy, Technology, Soustain. First break. – 2017. – Vol. 35. – № 6. – Pp. 59–64.

5. Mozambique approves Carol discovery development // Oil and Gas Journal. – 2016. – Vol. 114. – P. 10.

6. Characterization of organic matter from a stratigraphic sequence intercepted by the Nemo-IX well, Mozambique: Potential for hydrocarbon generation / F. Mussa, D. Flores, J. Rebeiro [et al.] // Energy exploration and exploitation. – 2018. – Vol. 36. – № 5. – Pp. 1157–1171.

7. Nhabanga O., Ringose P. Use of rock-physics analysis of well logs to determine compaction history of Cretaceous shales in the Rovuma basin, offshore Mozambique // Geophysical prospecting. – 2021. – Vol. 69. – № 1. – Pp. 1–13.

8. Nhabanga O., Ringrose P. Assessment of mudstone compaction in exploration wells in the Rovuma basin, offshore Mozambique // Heliyon. – 2019. – Vol. 5. – 9 p. – DOI: 10.1016/j.heliyon.2019.e02641

9. Overview of the petroleum sector in Mozambique // AAPG prospect and property. – London apex, 2019. – 31 p.

10. Petzet A. Deepwater, land discoveries high-grade East African margin // Oil and Gas Journal. – 2012. – Vol. 110. – № 4. – Pp. 70–74.

11. Salman G., Abdula I. Development of the Mozambique and Rovuma basins, offshore Mozambique. – Elsvier, 1995. – Pp. 7– 41.

12. Smith Ch. E. Africa, North America, Russia lead 2019 LNG plant investment plans // Oil and Gas Journal. – August 5, 2019. – Pp. 56–57.

13. Structural architecture differences and petroleum exploration of passive continental margin basins in east Africa / Wen Zhixin, Wang Zhaoming, Song Chengpeng [et al.] // Petroleum exploration development. – 2015. – Vol. 42(5). – Pp. 733–744.

14. Passive continental margin basin evolution and giant gas discoveries in offshore East Africa. Poster. / G. Zhang, Z. Wen, Z. Wang [et al.] // AAPG International Conference and Exhibition. Istanbul, Turkey, September 14–17, 2014.