The Windjammer exploration well is located in Rovuma Basin, Area 1 offshore Mozambique. The well lies at water depth of around 4,803ft. It is the first of four well offshore drilling programmes to test a deepwater block of 2.6 million acres over the frontier Rovuma Basin offshore.
The well is operated by Anadarko Petroleum Corporation (Anadarko) with around 43% interest. BPRL Ventures Mozambique BV and Videocon Mozambique Rovuma 1 Limited hold a stake of 11.75% each. Cove Energy Mozambique Rovuma Offshore Ltd has 10% interest, while Mitsui E&P Mozambique Area 1, Limited holds the remaining 23.5% interest.
Anadarko was awarded the exploration, production and concession (EPC) contract for offshore Area 1 of Rovuma Basin by the Government of Mozambique in December 2006.
The area covers over 2.5 million acres and is equal to around 460 offshore blocks of Gulf of Mexico.
The block was given to Anadarko under Mozambique’s second licensing round in 2006.
Windjammer exploration well geology
The Rovuma basin covers both onshore and offshore areas – more than 70,000km² of north-eastern Mozambique. The basin is located at the centre of the Rovuma delta, close to the border between Mozambique and Tanzania.
The length of the basin is around 400km and its breadth is 160km. The sedimentary succession of the basin was categorised into five stages. In the final stage, the Rovuma Delta systems were developed.
The entire Rovuma basin is classified into six offshore blocks. The offshore area has related varied reservoirs as those within the Karoo Supergroup, Jurassic and Cretaceous periods.
The area towards the south follows the Ibo horst trend with mapped structural closure of 1,200km². Towards the north, it is featured as tertiary Rovuma delta. Various structural and stratigraphic leads had already been found. The water depth ranges from 550m to 770m.
3D seismic studies were carried out over 3,300km2 in 2008. 2D seismic data from 5,000km2 was collected in 2009. The seismic data indicated a significant number of prospects structures in separate petroleum provinces. The presence of three toe thrust zones from north towards south at Palma, Lunique and Massala has also been indicated by the data.
The basin has various ranges of high-quality reservoirs rocks. It is expected that reservoirs will be found in the upper cretaceous-lower tertiary fan systems in the offshore region of the basin. This will be similar to Aptian Albian fans identified in the onshore areas of basin.
Windjammer well drilling
The 2D and 3D seismic data collected over the offshore area facilitate to start exploratory drilling campaign in late 2009. Anadarko plans to drill four deepwater exploration wells by 2010 and three shallow water exploration wells by 2011-2012.
Windjammer is the first well to be drilled. Located around 30 miles east of the Mozambique coastline, the well was drilled by Belford Dolphin drill ship.
The drilling of Windjammer began in December 2009 and it has now been drilled to an aggregate depth of around 14,000ft and to a water depth of 4,800ft. It touched an intermediate casing point and over 480ft of natural gas was identified in February 2010. The natural gas was found in high-quality reservoir sands and had a gross column of
Anadarko plans to drill over the same well further to acquire more geological information before hitting the total depth of the well. It is anticipated that the well will be drilled to a further 4,100m depth.
Belford Dolphin drill ship
Belford Dolphin, an ultra deepwater drilling ship, started from its port in Mozambique to start drilling over Windjammer prospect December 2009. The rig is owned by Fred Olsen Energy ASA and was built in 2000. It is 672ft long and 131ft wide.
The maximum depth that the rig can drill is 39,370ft and it can operate at a maximum depth under water of 10,000ft. The speed of the rig is around 10kt. The drill ship is planned to be returned to Collier prospect, which is some 50 miles from the Windjammer prospect.