In 2005 to 2007 ROC acquired a total of 722km 2D seismic data and 618km2 3D seismic data (573km2 coverage), in three separate surveys. A high resolution aeromagnetic survey was acquired in March 2006, covering the entire Cabinda South Block. A seven-well exploration drilling programme was completed from June 2007 to September 2008, utilising two rigs - the Simmons Rig 80 and the 100% ROC-owned Explorer rig. The first well, Massambala-1, discovered a shallow, heavy oil accumulation. As a result of 3D seismic reprocessing and laboratory analyses, the Joint Venture appraised the discovery with two wells in September-October 2008. The first appraisal well, MAW-1, confirmed a 9.5m gross heavy oil column and oil-water contact as expected. The second appraisal well, MAW-4, encountered the primary target deep to prediction and below the oil-water contact as determined from Massambala-1 and MAW-1. The second and third wells in the programme, Cevada-1 and Soja-1, had good hydrocarbon shows but neither is judged to be commercial and both wells were plugged and abandoned. The fourth well, Milho-1, was the first well in the current programme to specifically target a pre-salt structure. The well encountered a classic pre-salt sequence characterised by a thick world-class source rock, with significant oil and gas shows. This sequence overlies a thick sand interval with good reservoir quality. While non-commercial, the well provides a very important data point. The fifth well, Coco-1, produced 26oAPI oil and associated gas to surface during open hole drill stem testing of two separate intervals in the pre-salt sequence. The well was suspended as an oil discovery with the intention that it will be re-entered and tested. The sixth well, Sesamo-1, confirmed the existence of the pre-salt target reservoir sands, but there were no hydrocarbon shows. The final well in the exploration programme, Arroz-1 was plugged and abandoned after final wireline logging indicated only minor hydrocarbon shows. Preparations are in progress for the testing of the Coco discovery and the drilling of the Castanha-1 exploration well in 4Q 2009. |