In 2010 and early 2011 four significant gas discoveries were made by the Rovuma Offshore Area 1 partnership. These discoveries have precipitated an appraisal and testing programme aimed at achieving a final investment decision on a Liquefied Natural Gas (“LNG”) project by Q3–2013. The current estimate for the resource potential is some 12 trillion cubic ft (“TCF”) of gas and planning is already underway to evaluate the commercialisation of a project utilising a minimum of 6 TCF in a single train LNG project.
The Windjammer well is located some 30 miles off the coast of northern Mozambique in approximately 4,800 ft of water. Windjammer reported 480 net ft of natural gas pay in high-quality reservoir sands in two distinct horizons of Oligocene age sandstones, with a gross column of more than 1,200 ft. An additional 75 net ft of gas pay was discovered in the Palaeoscene target, bringing
the total net ft of natural gas pay in Windjammer to 555 ft. The well reached total depth at approximately 16,930 ft and was plugged and suspended in March 2010.
A coring programme as part of the appraisal work on this discovery commenced in February 2011 and the following is an analysis of this operation:
Windjammer #2, BP2 – Palaeoscene ||
Total Cut 121.0m |
Windjammer #2, BP3 – Oligocene Fan 1 ||
Total Cut 162.0m |
Windjammer #2, BP3 – Oligocene Fan 2 ||
Total Cut 110.0m |
Programme Total – Cut 393.0m, Recovered 389.7m (99.2%) |
The Barquentine well which is located two miles northeast from the Windjammer discovery reported a total of 416 net ft of natural gas pay in multiple high-quality sands in October 2010.
Specifically, the discovery well encountered more than 308 net ft of pay in two Oligocene sands that are separate and distinct geologic features, but age-equivalent to those horizons in Windjammer. This well also found an additional 108 net ft of gas pay in the Palaeoscene sands and the seismic data indicates that this deeper pay section is contiguous and appears to be connected to the 75 net ft of natural gas pay encountered in the Palaeoscene target at Windjammer.
Barquentine was drilled to a total depth of approximately 16,880 ft, in water depths of approximately 5,200 ft.
The Lagosta well encountered a total of more than 550 net ft of natural gas pay in multiple high-quality Oligocene and Eocene sands and was announced in November 2010. This discovery is located approximately 16 miles to the south of the Barquentine discovery and 14 miles to the southeast of the Windjammer discovery.
Lagosta was drilled to a total depth of approximately 16,307 ft, in water depths of approximately 5,080 ft.
The Tubarão discovery well encountered more than 110 net ft of natural gas pay and no water in a high-quality Eocene-age reservoir that is separate and distinct from the hydrocarbon accumulations in the three previous discoveries. The well was drilled to a total depth of approximately 13,900 ft in water depths of approximately 2,950 ft and was plugged and suspended in February 2011. Tubarão is located some 17 miles southwest of the Lagosta drill site.
The well bore at Tubarão was preserved by the partnership for potential utilisation in future testing.
Barquentine-2 appraisal well, spudded in Late June 2011, is located in Mozambique’s Offshore Area 1 of the Rovuma Basin and encountered more than 230 net feet (70 meters) of natural gas pay in high-quality Oligocene-age reservoirs. Barquentine-2 was the first appraisal well in the Windjammer, Barquentine and Lagosta complex.
Barquentine-2 appraisal well was drilled to a total depth of approximately 13,500 feet (4,100 meters) in approximately 5,400 feet (1,650 meters) of water. The results of the Barquentine-2 appraisal well, located approximately 2 miles (3 km) east-southeast of the Barquentine-1 discovery well, also indicated that the Oligocene reservoirs are in static pressure communication between the wells.
Other drilling results 2010
Two further wells have been drilled in the Rovuma Offshore block during 2010 as follows:
The Ironclad well location is 110 km south of the Windjammer gas discovery well and was drilled to evaluate the hydrocarbon potential of an aerially extensive Cretaceous deepwater fan complex in the southern part of the Rovuma Offshore block and in particular to determine the presence of oil in an area believed to have the geological parameters necessary for liquid hydrocarbon generation. Drilling operations ceased in August 2010 at a total depth of 17,403 ft, in a water depth of 3,445 ft, the well having penetrated 671 ft of targeted Cretaceous age sediments in two distinct fan lobes.
The well penetrated 125 net ft of oil and gas saturated sands in the upper fan lobe. The presence of oil was confirmed by geochemical analysis of rotary side wall cores taken from the well bore. The oil encountered in the Ironclad well is the first documented occurrence of liquid hydrocarbons in deepwater offshore East Africa. There were also significant gas shows reported throughout the drilling of the Cretaceous section.
An analysis of the logs and cores indicates that the sands, in which the oil and gas were encountered, have low porosity and permeability.
In April 2010 operations on the Collier well were suspended after encountering pore pressure issues at the top of the predicted reservoir objective, causing the operator to deem it unsafe to continue drilling. The Collier well did not penetrate or fully evaluate the entire predicted objective section. The well was plugged and suspended at approximately 10,500 ft.
Collier is located 45 miles off the coast of Mozambique at a water depth of 4,922 ft.
The Rovuma Offshore partnership has sanctioned a rapid exercise to appraise and evaluate the known gas discoveries to FID by Q3–2013.
A series of parallel programmes have been initiated in order to achieve this milestone.
A key objective in the development process is the securing of long term gas sales agreements that are sufficiently robust to underpin a decision to investment in the project.
A significant feature of the work in Rovuma Offshore block is the expectation of a return to the aggressive drilling programme in late 2011, following the arrival of the second rig, the Deepwater Millennium. At this stage it is expected that the Deepwater Millennium will be deployed for appraisal drilling and testing with the Belford Dolphin returning to drilling exploration wells.
The new 3D seismic acquisition will provide an important orientation tool and the partnership is confident that it will prove as accurate in predicting hydrocarbons in the new 3D area as it has to date in the existing 3D area.
Currently the partnership has confirmed gas discoveries in the Palma Gas Field and at Tubarão and has encountered oil in Ironclad. There are a number of existing high priority targets within these proven areas that will be attractive for new exploration drilling including Atum, Orca and Trawler (Palma Gas Field) and Barracuda. In addition the results from the new 3D programme will provide a greater technical understanding on the targets in the south of the block, Caravel, Black Pearl and Bireme and in the northern area Linguado, Golfino and the Miocene targets in the north-east of the block.
Bharat Petroleum ||
ENH (carried interest) ||
| Cove || 8.5% |