Operators rev up activities offshore West Africa

Offshore West Africa remains one of the world's most recognized exploration and production provinces and one of the most promising regions in terms of future development opportunities.

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Bruce Beaubouef
Managing Editor

Offshore West Africa remains one of the world's most recognized exploration and production provinces and one of the most promising regions in terms of future development opportunities.

State-owned entities, international oil companies, and drilling contractors continue to advance plans for drilling campaigns, development projects, and floating and subsea production facilities. A sampling of some of the latest news from some of the most recent projects is provided below.

Liberia

In September, African Petroleum reported that it had completed Apalis-1, the first deepwater well off Liberia in block LB-09. The well was drilled to a depth of 3,665 m (12,024 ft) and encountered oil shows in several geological sections, including the shallower (Tertiary) and deeper (Cretaceous). Petrophysical analysis indicates the presence of hydrocarbons.

Apalis-1 also confirmed the presence of organic oil-prone source rocks, suggesting that LB-08 and LB-09 (also operated by African Petroleum) are in a prospective oil basin. The company says it now plans to speed up a multi-well drilling program on the 25-plus exploration prospects it has identified on the blocks, with the first of these wells due to be drilled in the fall and early in 2012.

Congo

Meanwhile, Lundin Petroleum has started drilling the exploration well Mindou Marine-1, located offshore Congo, in block Marine XI. The planned depth is about 3,400 m (11,155 ft) and the well will be drilled by the semisubmersibleENSCO 5003. Drilling is expected to take 50 days. The well is targeting a pre-salt Toca formation carbonate reservoir within a combination structural and stratigraphic trap. This well will fulfill the Phase II drilling commitment on the license and is the first of a two to three well program on blocks Marine XI and XIV.

Angola

Development activities are also under way offshore Angola. MSI says it has installed a current mooring system and a metocean buoy in block 16 for Maersk Oil, where water depth is around 1,200 m (3,937 ft). The main aim of the program is to collect site-specific current, wave, and meteorological data through the entire water column to help optimize design of a proposed floating production system.

The current mooring comprises current profilers, current meters, and CTD. The 1.8-m Axys Watchmate metocean buoy comprises wave, surface current, and meteorological sensors. The moorings will be serviced every three months for a year. Data from the metocean buoy is transmitted in real-time to MSI's offices for the client to access. Equipment was deployed from theRagnhild K vessel, mobilized from Luanda, with assistance from MSI's local partner Zamexi.

Elsewhere off Angola, oil flow has begun at the Pazflor field in block 17, according to operator Total. With reserves estimated at 590 MMbbl, production is expected to ramp up to 220,000 b/d. Pazflor is 150 km (93 mi) offshore Luanda in water depths from 600 to 1,200 m (1,968 to 3,940 ft). It has 180 km (112 mi) of subsea lines that tie in 49 subsea wells to an FPSO. The production system features subsea gas/liquids separation units and pumps to move the viscous oil to the surface.

Equatorial Guinea

Oil and gas development plans for the deepwater areas offshore Equatorial Guinea are on the rise. Development of the Noble Energy-operated Aseng field in block 1 is ahead of schedule. Partner PA Resources says start-up should now occur by the end of this year, having previously been estimated at 1Q 2012. Production should then build steadily toward the forecast plateau.

All the development wells have been drilled and completed, and subsea installation activities are ongoing. An FPSO was expected to depart Singapore in September, arriving at the field early this month to begin hookup and commissioning.

Development of the Alen field, the second project in the block, also is progressing. Construction of the production platform has begun, and the wellhead jacket is largely complete.

Subsea development drilling and completions should start this summer, with the semisubmersibleAtwood Hunter due to drill and complete one gas injection well and complete two previously drilled wells for gas injection. A second rig, the Atwood Aurora jackup, will arrive in October to complete one existing well for production and drill two new producer wells. First condensate production is scheduled for late 2013.

On the adjacent block O license, results from a recent appraisal well on the Diega-Carmen discovery suggests this field will be the candidate for a tieback to the Aseng/Alen infrastructure, PAR claims. Carmen-Diega also extends into block 1.

Ghana

Meanwhile, Kosmos Energy is advancing plans for developments offshore Ghana. The company reported a light oil discovery on the West Cape Three Points block in late August. Analysis, including wireline logs, pressure tests, and fluid samples, indicates the well found 33 m (108 ft) of pay in four good-quality Turonian sands.

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Kosmos Energy is advancing plans for developments offshore Ghana, and theAtwood Hunter drilled the Akasa-1 well to TD of 3,918 m (12,854 ft) in 1,158 m (3,798 ft) of water as part of that program. Photo by Anna Clopet, courtesy Kosmos Energy

TheAtwood Hunter drilled the Akasa-1 well to TD of 3,918 m (12,854 ft) in 1,158 m (3,798 ft) of water. Kosmos says the near-term drilling plans include the Cedrela exploration prospect, which is currently under Force Majeure discussions, and two appraisal wells at the Teak discovery on the West Cape Three Points block. In addition, the company and its partners plan to drill at least two appraisal wells at the Enyenra field on the adjacent Deepwater Tano block offshore Ghana.

The company also announced successful flow test rates at the Tweneboa discovery on the Deepwater Tano block. At Tweneboa-4, the flow test resulted in sustained rates of approximately 3,500 b/d of condensate and 30 MMcf/d of natural gas. A drillstem test at Tweneboa-2 flowed at a rate of 6,500 b/d and 5 MMcf/d. The data from these tests is being used to optimize development plans for the Tweneboa/Enyenra complex.

To learn more about activities off West Africa, please make plans to attend Offshore West Africa, the region’s premier technical forum focused exclusively on West Africa’s offshore oil and gas industry, Jan. 24-26, 2012, at the International Conference Centre in Abuja, Nigeria. For additional information or to register for the conference, please visit the website athttp://www.offshorewestafrica.com/index.html.

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