24 4d fixed installation seismic
➠
Oil Company (TPAO) and in Norway, StatoilHydro and The company expects to see a ‘reasonable’ number
WesternGeco conducted an extensive collaborative full- of coil shooting surveys this year and to increase sharply
azimuth survey design and modeling project to evaluate thereafter, especially as results become available from the
multiple wide-azimuth (WAZ) configurations including 2009 programme.
coil shooting over the Heidrun field. The upshot was that, Western Geco’s work was recognised at this year’s
not only was coil shooting a more effective strategy than Offshore Technology Conference in Houston, by being
traditional wide azimuth (WAZ) acquisition, it also gave awarded one of the coveted OTC technology awards.
better imaging results for complex and heavily faulted Staying on the theme of being not totally new
Heidrun, which lies in 350m of water. technologically but clearly very new to the marketplace
In September 2008 StatoilHydro R&D commissioned a in terms of application is PGS’s Geostreamer technology,
survey resembling a ‘dahlia' flower pattern pattern with which it makes much of in its latest financial results
18 intersecting coils This geometry provided full azimuth, review.
high fold data over a 2.6 km x 26 km target area, plus GeoStreamer made its technical debut in late 2007.
sufficient surrounding aperture to provide 3D migrated The system was hailed as being the first ever towed
sections that can be compared with previously acquired streamer to successfully house both pressure and velocity
conventional seismic data. sensors, so enabling delivery of enhanced resolution, plus
The Heidrun survey was completed over a 4 day deeper penetration of geology to provide a higher quality,
period, with a coil radius of 5.6 km, and 10 streamers, de-ghosted seismic image.
each 4.5 km long, separated by 75 m, resulting in clearer PGS started equipping vessels last year and,
imaging, notably improved fault definition in the reservoir importantly, rapidly secured contracts in the US Gulf of
section, compared to the conventional survey data. In Mexico and the North Sea. First out of the gate in contract
addition, the flanks of the Heidrun structure are now well terms was work for StatoilHydro kicking off mid-June
imaged. 2009.
Western Geco says the single vessel coil survey The Gulf of Mexico work was announced late 2008,
technique is particularly attractive for collecting small with PGS stating that it was to acquire a new multi-client
to medium-sized 3D full-azimuth datasets. For larger 3D seismic survey in the area of DeSoto Canyon located
surveys, like those that are now taking place in the highly offshore Alabama and Florida in the Gulf of Mexico.
active Gulf of Mexico area, using multiple vessels may be Covering approximately 250 deepwater OCS blocks
a more cost-effective option. (5828 sq.km), the new programme named Discovery is
While it was thought that additional noise level caused focused on a lightly explored sector recently opened for
by steering the streamers in circles might be a problem, leasing in the Central and Eastern GOM planning areas.
benefits have outweighed this perceived disadvantage. Importantly, PGS said it would acquire the DeSoto
Western Geco says that coil shooting has Canyon data using GeoStreamer. Indeed, this contract
demonstrated itself as an efficient and effective survey marks the industry’s first 3D implementation of
method to acquire full azimuth data over small to medium GeoStreamer yielding higher fidelity data.
sized areas and a particular benefit is that it requires only PGS Atlantic Explorer started the nine-month
one vessel, so helping cut costs. campaign at the turn of 2008-09. BP is an underwriter for
the survey; also a technical collaborator.The Norwegian
group said the project has attracted wide interest from
oil companies with lease holdings in the area and those
wishing to acquire new acreage or those seeking farm-in
opportunities. Data acquired utilising GeoStremer will be
made available at the upcoming US Gulf of Mexico lease
sale in 2010.
Turning to the North Sea and in the quest for ever
more enhanced seismic resolution, better deep imaging,
operational robustness and excellent final results, PGS
has just started the first ever North Sea season for
GeoStreamer.
That programme started in April and comprises the
gathering of both multi-client and contract 3D data.
The campaign kicked off with a 1600sq km survey for
Lundin Norway based around the Luno discovery in the
Norwegian North Sea. As for the upcoming StatoilHydro
contract, it too is scheduled for the current summer. In
this instance, the client is also the first customer for the
Fig. 2. Geostreamer is a dual sensor seismic streamer developed by
Ramform Sterling, which is PGS’ second new S-Class
PGS, and is being used in the North Sea for the first time.
Ramform vessel, which is due for delivery in July 2009. l
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