GEOSCIENCES
Gene Kliewer - Houston
Africa
CGGVeritas plans to acquire two 2D seismic surveys offshoreGabon and to have the data before the 10th Gabonese License Round scheduled between June and December 2010. That license round will be the first in the country since 1999. It focuses on deepwater pre-salt prospects thought to be analogous to offshore Brazil.
The Zone Nord survey will cover 2,200 km (1,367 mi) and target the Tertiary and Cretaceous plays.
The Zone Sud survey will be a very long offset run aimed at imaging beneath the Aptian salt. Zone Sud is part of a three-phase program. Phase 1 will include basin-wide depth modeling using existing data and a new test line. Phase 2 will be a gravity gradiometry survey to detail salt architecture. Phase 3 will be targeted 2D work. At the end of this program, additional work, including 3D, will be considered.
“The complexity of the salt bodies in the south Gabon basin would warrant 3D seismic coverage,” says Steve Toothill, CGGVeritas EAME chief geologist. “However, to shoot a 3D survey over the whole area of more than 50,000 sq km (19,305 sq mi) would take too long and be prohibitively expensive. A well planned 2D survey, specifically designed to target below the salt, will be sufficient to delineate structures. This will allow oil companies to evaluate the area, make their bids and then follow up with high-specification 3D surveys, such as wide-azimuth, to provide better illumination below the salt.”
Earlier this year, Gabon’s Direction Generale des Hydrocarbures selected CGGVeritas to assess the hydrocarbon opportunities in Gabon’s deepwater, assist with the upcoming Licence Round and work programs, and conduct a targeted seismic program.
OffTunisia, Circle Oil Plc has done a 2D seismic acquisition program in the Mahdia permit. Some 411 mi (501 km) of infill, full-fold 2D data was acquired by PGS Marine. Processing is under way leading to interpretation and integration into existing data.
“The onboard preliminary processing of the acquired data clearly shows the target sequences and we are very pleased to progress our studies in this prospective area,” says Circle Oil CEO David Hough. “The integration of this new data will allow us to complete our mapping and prioritize the multiple undrilled prospects which have already been mapped from the existing datasets.”
Mahdia covers 1,459 sq mi (3,780 sq km). Shell and Total have found commercial oil fields in and around the area. Circle holds 70% and Tethys Oil and Mining Inc. holds the remaining 30%. A commitment well must be drilled by mid-2012.
Latin America
Petrobras ofBrazil and Schlumberger have agreed to cooperate on pre-salt reservoir research and development. Four specific projects are listed in the agreement:
- 1. Electromagnetic technology to improve deep reservoir characterization
- 2. Seismic data analyses technologies
- 3. Nuclear magnetic resonance technologies to help characterize complex reservoirs
- 4. H2S electrochemical sensors.
According to Petrobras, there are six other projects which may come under the three-year, $10-million agreement.
As part of the program, Schlumberger plans to open a research center on Fundao Island in Rio de Janeiro. It will be the first such center in the Southern Hemisphere and will link to centers in the US, Norway, Saudi Arabia, Canada, and Singapore.
SCAN Geophysical should be running a 2D seismic study offshoreChile following the award of a Letter of Intent from Direccion Nacional de Fronteras y Limites Estado, Ministry of Foreign Affairs.
TheGeo Searcher is scheduled to use an 8,000-m (5-mi) solid streamer system in combination with a 4,200 cu in. source. The project is scheduled to be complete before May.
A project off south and east of theFalkland Islands for Falkland Oil and Gas Ltd. by Fugro Meridian is complete, the company reports. Site surveys were done over four areas selected by operator BHP Billiton and FOGL. Work includes high-resolution 2D seismic data acquisition plus bathymetric and seabed imaging surveys. Wave and current meters were deployed from the British Antarctic Survey vessel James Clark Ross. Fugro’s Saltire conducted a geotechnical boring program of the top 200 m (656 ft) of seabed sediment to help with conductor and casing designs. According to Tim bushel, CEO of FOGL, this completed the final phase of offshore activity prior to drilling.
US OCS
TGS-NOPEC Geophysical and WesternGeco have resumed data acquisition for the Freedom Wide Azimuth multi-client project in Mississippi Canyon of theGulf of Mexico with two recording vessels each towing 10 streamers.
The total project covers some 15,000 sq km (5,792 sq mi) and as such is one of the largest-ever wide-azimuth programs. Work began in January 2008 and was interrupted in October 2008. It is about 50% complete and is scheduled to be done in August 2009.