Ghana
In 2008, the Group focused on the Phase 1 development of the Jubilee field, an appraisal campaign to determine the ultimate field size and exploration work to establish the upside potential of the remainder of the basin.
Outstanding exploration success
In February 2008, the Odum field was discovered in the West Cape Three Points block, some 13 km east of Jubilee. This discovery opened up a new Campanian geological play in a previously unexplored reservoir interval. In November 2008, Tullow drilled the Ebony-1 commitment well in the Shallow Water Tano block which encountered normal pressured oil sand and an over-pressured gas-condensate sand up-dip from Twenebo. Data acquired from the recent Tweneboa-1 well demonstrated that although charged through Tweneboa, Ebony is not presently in pressure communication and as a result Ebony was determined to have a sub-commercial resource potential. Tullow will therefore relinquish its interest in the Shallow Water Tano licence.
In March 2009, the Tweneboa-1 exploration well, in the Deepwater Tano licence, discovered a highly pressured light hydrocarbon accumulation of up to 1.4 billion barrels of oil equivalent with a liquid yield currently considered to be in the range of 30 to 40%. The well encountered 21 metres of net pay on the edge of a giant 200 sq km Turonian fan system related to the Jubilee play. Appraisal drilling will now be required to test core areas within this stratigraphic trap where thicker Turonian reservoir sections are mapped.
The substantial Teak complex is one of an inventory of prospects located in the region. Drilling is scheduled to commence on Teak in the fourth quarter of 2009.
Highly successful Jubilee appraisal programme
Three exploratory appraisal wells, Mahogany-2, Hyedua-2 and Mahogany-3, were drilled on the Jubilee structure during the year. Each of the wells were approximately 5 km away from the original discovery well and each intersected considerable hydrocarbon columns in the Upper and Lower Mahogany sands which are both in lateral pressure communication. The Mahogany-3 well also discovered oil in a third and potentially extensive underlying sand, Mahogany Deep, which is being considered for appraisal drilling in 2009. These results led to a significant upgrade in the gross resource base for the field with the most-likely P50 case being upgraded to 1.2 billion barrels with an upside potential case of 1.8 billion barrels. It is anticipated that the initial development area has gross reserves of 490 million barrels resulting in Tullow booking its net share of 170 million barrels at year-end. Further extension of the eastern part of the Jubilee field may be targeted through an additional Mahogany exploratory appraisal well before the end of 2009.
Flow tests performed on both Mahogany-2 and Hyedua-2 confirmed that Jubilee is a highly productive and well connected reservoir and that once the wells have been configured for long-term production, they should be capable of producing at rates in excess of 20,000 barrels of 37° API crude oil per day.
Blackford Dolphin rig drilling Hyedua-2 appraisal well offshore Ghana.
Jubilee Phase 1 on schedule for first oil
Significant progress has been made on the Phase 1 development of the Jubilee field and the project is on schedule to deliver first oil in the second half of 2010. The field has been unitised across the Deepwater Tano and West Cape Three Points blocks with Tullow named as Unit Operator. In addition, a joint venture project team has been established with Kosmos Energy appointed as the Technical Operator. The Phase 1 Plan of Development has been submitted to the Ghanaian Government along with the related Unit Agreement and both are expected to be approved in the near future following final resolution of the gas development plan.
The Phase 1 development plan involves drilling a total of 17 wells, for oil production, water injection and gas injection, which will be tied back to a Floating Production Storage and Offtake vessel (FPSO) with a production capacity of 120,000 bopd. Sufficient rig capacity has been contracted for the development and the first dedicated development well is under way. Contractors have been selected for all major components of the project facilities and construction work has commenced. To support all offshore activities, an operational organisation and associated infrastructure have been established in the city of Accra and the port of Takoradi.
The partnership has also agreed, in principle, a gas development plan with the government which will include the capability for gas re-injection and a gas export pipeline to the coast where a gas processing plant will be constructed. Jubilee will be a foundation supplier to this gas infrastructure and commercial agreements will be negotiated in 2009.
In light of continued exploration and appraisal success, the joint venture will commence work to evaluate the potential for further phases of development for the Jubilee field during 2009.
