West & North Africa
Mauritania & Senegal
Production from the Chinguetti field in Mauritania continued to decline but at a reduced rate with full year net production averaging 1,400 boepd (2010: 1,500 boepd). Potential for further production optimisation in 2012 is being evaluated.
Two exploration wells were drilled in Mauritania in the first half of 2011. The Cormoran-1 well in Block 7 intersected four stacked hydrocarbon accumulations. In the deepest of these sections the well discovered highly pressured rich gas in the Petronia prospect, providing an encouraging test of our concept that Tullow’s core play in Late Cretaceous turbidites extends into northern Mauritania. The Gharabi-1 well in Block 6 encountered poorly developed water-bearing reservoir and was plugged and abandoned in February 2011. The well was drilled by the operator to meet a commitment on the block and the result has no impact on Tullow’s future plans for its Mauritanian acreage.
Tullow signed the new C-10 exploration Production Sharing Contract (PSC) in Mauritania on 27 October 2011 at an operated equity of 59%. This licence, the exploration area of the previous PSC A and PSC B, is over 10,000 sq km in area and carries a two-well commitment in the first three years. Tullow is planning a number of exploration activities across its various exploration licences in the Mauritania-Senegal basin during 2012 including 3D seismic acquisition and drilling.
In addition, Tullow has been granted extensions to the discovery areas of the previous PSC A and PSC B licences and increased its equity in these licences to 67.3% and 64.1% respectively. These licences, which Tullow now operates, contain the Banda, Tevet and Tiof oil and gas discoveries. The development of the Banda oil and gas discovery is progressing with project concepts under review.
The Ceiba field performed above expectation in the first half of 2011 but fell below 15,000 bopd gross in the second half of the year due to delays to the workover programme. Gross production averaged 19,915 bopd in 2011 (2010: 27,600 bopd). A major workover and infill drilling programme is now underway to restore production to higher levels. The Ocean Valiant rig moved to the field in January 2012 and began work on the first of the three well workovers before commencing the drilling of eight infill wells.
Production in the Okume Complex fell in the second half of 2011 due to a delay on the Akom North field tieback; gross production averaged 71,680 bopd in 2011 (2010: 82,360 bopd). The Akom North well was drilled and completed in late December 2011 and first oil was produced in January 2012. A major infill drilling campaign is planned with a rig secured to start operations in July 2013.
The results of the 4D seismic, shot in 2011, have been used to support the drilling campaigns in both fields.
Net production in Gabon averaged 12,700 bopd for the year (2010: 12,850 bopd). Appraisal and infill drilling has been very successful throughout 2011 with over 120 wells being drilled and completed resulting in production being sustained and reserves replacement of 351%, an exceptional result in this mature area. This level of development and drilling activity is expected to be sustained in 2012.
In June 2011, Tullow completed a 20% farm-in to the Perenco-operated onshore exploration blocks DE-7 and Ogueyi. However, the Big Oba prospect in DE-7 and the Nkongono prospect in the Ogueyi block both proved unsuccessful and the Ogueyi block has since been relinquished. Acquisition of further 2D seismic data is planned to outline additional prospects in the DE-7 and Nziembou blocks; a multi-azimuth 3D survey is planned on the offshore Arouwe block in the first quarter of 2012. The seismic processing over Kiarsseny is now complete and interpretation is ongoing; the intention is to drill two exploration wells back-to-back, commencing in the fourth quarter of 2012.
Net production from the M’Boundi field was below expectations averaging 3,000 bopd in 2011 (2010: 4,000 bopd). Production volumes from the field fell in the second half of the year following issues with the water injection system which have now been resolved. Infill drilling and workover activity continued throughout the year with 19 wells drilled. Production volumes are expected to recover in the first quarter of 2012 as sustained water injection rates continue following the installation of a second high-volume pump in the field.