JUNE-04-2012: O&G JOURNAL ARTICLE Interesting comments made by Kosmos - see link and comments below: https://www.ogj.com/articles/print/vol-110/issue-06/special-report-exploration/world-s-frontier.html
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World's frontier basins draw exploratory efforts
Frontier basins around the world are in line for 3D seismic surveys and key exploratory wells as the 2012 midpoint nears.
This article provides capsules on five randomly selected offshore and land exploratory programs in which supermajors and small operators are involved.
Covered here are the Guyana-Suriname basin on the northeastern margin of South America, the Alakol basin in eastern Kazakhstan near the border with China, a new province just east of the Mozambique Channel, an exploration frontier in Nigeria's Niger Delta, and activities in southern Chad basins near the boundary with Central African Republic.
Guyana-Suriname basin
Several companies have taken acreage along South America's northeastern margin where the geology mirrors that of the Tano basin offshore Ghana, where world class deepwater oil discoveries have been made including giant Jubilee field by Kosmos Energy and partners in 2007.
Participants in the area off Guyana, Suriname, and French Guiana include affiliates of ExxonMobil, Shell, Tullow Oil PLC, Statoil ASA, Total SA, Kosmos Energy, Inpex Corp., Murphy Oil Corp., Northern Petroleum PLC, and CGX Energy Inc. (Fig. 1).
A Tullow-led group fanned the flames of this already-hot spot late last year when its Zaedyus wildcat found 72 m of net oil pay in two turbidite fans on the Guyane Maritime block off French Guiana. The well went to 5,711 m in 2,048 m of water 150 km offshore (OGJ Online, Sept. 9, 2011).
Meanwhile off Guyana, CGX Energy said it found water-bearing sandstones with hydrocarbon shows in the Eagle-1 wildcat on its Corentyne license, and a group led by Repsol Exploracion is drilling the Jaguar-1 wildcat on the Georgetown license targeting the Upper Cretaceous.
Tullow and Total shot 3D seismic off French Guiana in late 2009-early 2010, but what is known about the basin comes primarily from 2D data and wells drilled in the 1980s and prior, said Kosmos Energy. More 3D is to be acquired, but the weather window is tight because of stiff currents that flow northwestward from the Amazon River delta.
A drillship is to arrive in June to begin a comprehensive exploratory and appraisal program off French Guiana for the Tullow group. The rig will appraise Zaedyus and explore deeper objectives at the first well, then drill a wildcat.
The Tullow group was to have launched a 3,000 sq km 3D program on Suriname Block 47 in May 2012 and off French Guiana, and in June it plans to shoot the 4,700 sq km Eastern Slope 3D survey and the 620 sq km Cebus 3D survey on either side of the Cingulata fan system containing Zaedyus and other mapped turbidite fans.
The heavy crude in Suriname's coastal Tambaredjo field, producing since the early 1980s, appears to have originated in a deepwater source kitchen. The 16° gravity crude is reservoired at 600-1,300 ft (OGJ, Oct. 12, 2009, p. 36).
Paul Dailly, senior vice-president, exploration, said Kosmos Energy did a year's regional study of the South American continental margin from Brazil to Trinidad in order to understand the regional source rock and reservoir regimes. The company's blocks 42 and 45 off Suriname, southwest of Tullow's Block 47, are in one of the basins that the company high-graded as a result of the regional study.
"The bit that's specific to Suriname is the stratigraphic trapping geometries, and we need the 3D for that," Dailly said.
"This basin has been explored in the past in shallower water and up in the Tertiary and has not had a lot of success to date, but we're looking for stratigraphic trapping geometries buried in the guts of the basin closer to the source rocks…we think that in that position there's a lot of potential for trapping geometries that have been overlooked in the past," he said. "The concept is an extension of the Upper Cretaceous stratigraphic play that we unlocked on the West African side of the margin."
The Tullow group's Zaedyus well has to some extent validated the play concept, Dailly said. The 3D data will also indicate whether the basin harbors features of the size Kosmos Energy is seeking, i.e., a potential of at least several hundred million barrels of light, sweet crude.
Kosmos Energy is contacting seismic contractors now to shoot 3D data this year and might conceivably be in a position to drill as early as 2014.
As it has done off Ghana, Kosmos Energy likely would employ a floating production, storage, and offloading vessel development assuming there were a discovery off Suriname of sufficient size, Dailly said.
Suriname, where the two Kosmos Energy blocks total 2.8 million acres, is the company's first exploratory venture outside West Africa.
The Suriname entry is part of a Kosmos Energy strategy to drill two to four frontier basin-testing wells per year starting in 2013. Besides Suriname, Kosmos Energy has taken positions in Morocco, Mauritania, and Cameroon.