Tullow draws up offshore Ghana Jubilee oil field expansion plans

March 14, 2012
Phase 1A development drilling started last month on the Jubilee field off Ghana, according to operator Tullow Oil.

Offshore staff

LONDON --Phase 1A development drilling started last month on the Jubilee field off Ghana, according to operator Tullow Oil.

Under the$1.1-billion program, eight new wells will be drilled comprising five producers and three water injectors. The first of these wells should come onstream in late June.

Phase 1 remedial work continues – measures will include acid stimulations and recompletions of some underperforming wells. This overhaul, and the additional Phase 1A wells, should allow production to build toward the FPSO’s design capacity of 120,000 b/d.

Tullow expects Jubilee’s production to average between 70,000 and 90,000 b/d in 2012, depending on the well performance achieved from the Phase 1 recovery program and the execution schedule of the Phase 1A wells.

In the Deepwater Tano license containing Jubilee’s western portion, studies continue on the Tweneboa, Enyenra, and Ntomme fields oil and gas/condensate fields, now known collectively as TEN.

Tullow expects to develop all three accumulations via an FPSO under an integrated subsea cluster development scheme. FEED work started last August, and a design competition is under way involving three FPSO contractors. Subsea FEED is nearing completion and tenders for this work are being prepared.

Some time this summer Tullow expects to submit the TEN Plan of Development (PoD) and a formal declaration of commerciality to Ghana’s Government. It anticipates achieving first production from TEN 30 months after government sanction.

The company has identified further exploration prospects in the license. Wells that could be drilled are Wawa-1, targeting hydrocarbons that may have moved to a trap up-dip from the TEN fields; Sapele-1, immediately south of the Jubilee, testing a prospective turbidite lobe; and Tweneboa Deep-1, a prospect underlying the TEN fields.

Offshore neighboring Cote d’Ivoire, drilling is under way in the deepwater Kosrou prospect for Tullow in block CI-105. Operations should be completed in April. Next up will be a well on the potentially high-impact Paon prospect in block CI-103.

On the other side of the West Africa transform margin, Shell has assumed operatorship of the block containing last year’sZaedyus-1 oil discovery off French Guiana. This encountered 72 m (236 ft) of net oil pay in two turbidite fans.

Tullow says an extensive data gathering program followed, including side tracking of the well to cut a core through the reservoir and compile essential data. A liner was run over the main oil-bearing reservoir and the well was suspended for future re-entry.

The partners are discussing a follow-up program which will include 3D seismic acquisition and drilling, probably starting mid-2012. This will begin with an appraisal well on Zaedyus and will be followed by an exploration well on a neighboring prospect.

Offshore Suriname, Tullow farmed down a 30% interest in block 47 to Statoil in December. Planning is under way to acquire over 2,500 sq km (965 sq mi) of 3D seismic, with the program due to start this spring, subject to environmental approvals. Acquisition should take around four months to complete.