Overview
The Ogooue Delta complex is a proven hydrocarbon province, where over 2,000MMbbl of oil and 900Bcf of gas have been discovered since the 1960s
The Mbeli Marin, Ntsina Marin, Manga Marin and Gnondo Marin blocks are situated west and north of the petroliferous Ogooue Delta complex. The Ogooue Delta complex is a proven hydrocarbon province, where over 2,000MMbbl of oil and 900Bcf of gas have been discovered since the 1960s.
Interest
The Group was awarded a 100% interest in the four deepwater blocks on 16 March 2005. The Government of Gabon has a 10% beneficial interest in three of the blocks (Gnondo Marin, Ntsina Marin and Mbeli Marin) and a 15% beneficial interest in relation to the Manga Marin block, in each case, upon declaration of commerciality.
Exploration
The Blocks were awarded in March 2005 and during the first licence term Ophir carried out an extensive review of the regional petroleum geology. Significant progress was made in understanding the source and migration risks, reservoir distribution and trapping mechanisms and a variety of prospect types was identified across all four blocks.
The second three year license term for Ntsina Marin and Manga Marin commenced on 14 September 2007 and Ophir drilled two independent play types in late 2008 using the Deep Venture drillship. Frake Noir-1 was drilled in Ntsina Marin and Ngollon-1 in Manga Marin and fulfilled the PSC work obligations for the two permits. Although these wells did not intersect live hydrocarbon columns they significantly improved the understanding of the petroleum system within the blocks.
Whilst the drilling campaign was being carried out, extensions to the first term were granted for Mbeli Marin and Gnondo Marin and the second three year license term for Gnondo Marin and Mbeli Marin commenced on 14 September 2009.
Following an assessment of the drilling results, together with continued regional play system analysis, Ophir has switched the focus of exploration efforts to the significant upside of the pre-salt potential and the Government has agreed to certain modifications of the work programme to allow for the effective investigation of this play. This has always been recognised as a significant potential “prize” in the area but poor imaging and high well costs have precluded exploration of the play offshore in the North Gabon Basin up to now. In 2009, Ophir carried out a 300km 2D seismic survey to test the imaging ability of deep tow, dual receiver long cables. The objective was to test this new acquisition method to image the sub-salt stratigraphy. The outcome was encouraging and as a result, Ophir proposes to acquire a deep tow, dual receiver 3D seismic survey.
To complement the new seismic data, Ophir acquired a 2,000km2 marine gravity gradiometry survey over Mbeli Marin and Ntsina Marin early in 2010. Gradiometry is a three component gravity acquisition method which provides a significant improvement in data fidelity over standard gravity methods. The Gabon survey produced excellent results and has provided valuable information on the structure and thickness of the pre-salt sedimentary section. For further information regarding the gradiometry methodology please refer to ARKeX.
Licence Details
| Licence Name | Mbeli Marin, Ntsina Marin, Manga Marin, Gnondo Marin |
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| Basin | North Gabon |
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| Gross Area | 3,384km2; 3,299km2; 3,455km2; 2,574km2 |
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| Depths | 180 to 2,200m; 200 to 2,400m; 100 to 2,500m; 100 to 2,500m |
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| Licencee: |
Interest: |
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| Ophir Gabon (Manga) Limited (Operator) | 100% Manga |
| Ophir Gabon (Gnondo) Limited (Operator) | 100% Gnondo |
| Ophir Gabon (Mbeli) Limited (Operator) | 50% Mbeli |
| Ophir Gabon (Ntsina) Limited (Operator) | 50% Ntsina |
| Petrobras (JV Party) | 50% Mbeli & Ntsina |
Images
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A comparison of conventional satellite gravity data with the new Full Tensor Gravity Gradiometry (FTC) data acquired by ARKeX in the Mbeli and Ntsina blocks. The very high resolution FTG image is achieved by recording the gravity field as five independent components as opposed to measuring only the magnitude of the gravity field in a conventional gravimeter. The FTG data enables much improved definition of structure and lithology interfaces (salt/sediment).
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By applying variable wavelength filters to the high resolution FTG data, it is possible to filter out the unwanted data above and below the target interval. The end products are effectively depth slice maps focussing only on the level of interest. From left to right the FTG maps are imaging the geology at decreasing depths.
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Interpreted Section through Ntsina Marin, showing play types
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Ophir test deep tow 2D line acquired using PGSs GeostreamerTM dual sensor technology. There is a marked improvement in signal penetration beneath the salt, resulting in enhanced resolution, and improved imaging.
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Conventionally acquired seismic line from the Tolo 3D in the Mbeli block. There are very few primary reflectors within and below the thick salt.
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