CoNTrollED soUrCE ElECTroMAGNETiC rEsoNANCE 15
Sub-bottom survey of geological
boundaries in the Arctic Circle
Fig. 1. The CCGS
Though there may
Nahidik was
be vast, technically commissioned as
recoverable oil and a buoy tender on
gas reserves beneath
the MacKenzie
the sea north of the
River but since
Arctic Circle there are
2001 has been
enormous challenges
used for science
when operating
in such a harsh
programmes
environment. Neil
by Canadian
MacDonald reports.
Government
agencies.
Unter dem Meer
nördlich des
Polarkreises sind zwar
Photograph: Geological
möglicherweise noch
Survey of Canada
riesige Öl- und (GSC).
Gasvorkommen
vorhanden, deren
Erschließung technisch
machbar ist, jedoch
eohazard surveys are standard carried out by the Canadian Coast Guard vessel
bereitet das Arbeiten practice prior to offshore drilling in Nahidik under the auspices of the Geological
unter solch widrigen all seas as they detect the presence Survey of Canada’s (GSC) geohazards mapping
Umständen enorme G
of shallow gas-bearing formations, programme lead by Steve Blasco. Their private
Probleme. Ein Bericht
active faulting and potential hydrate zones but partner, Canadian Seabed Research Ltd. (CSR)
von Neil MacDonald.
the presence of permafrost under the seabed based in Nova Scotia, handled the recording part
in this region, which could create unstable of this mission.
Aunque existan unas
foundation conditions for natural gas production
reservas ingentes de
and gas rigs, poses an additional difficulty for
Seafloor imaging
crudo y de gas
operators. Canadian Seabed Research is a well established
técnicamente company of geophysicists, hydrographers
recuperables bajo el
Reflected acoustic signals
and survey engineers operating worldwide
mar situado al norte
One area under investigation for oil and gas undertaking a variety of marine geophysical
del Círculo Polar
resources includes the Beaufort Sea, north of surveys including precise positioning, pipeline
Ártico, operar en un
Canada’s Yukon and Northwest Territories. and cable route surveys, seafloor imaging as
ambiente tan agreste
plantean unos desafíos
The technique used well as sub-bottom
imponentes. Neil
to investigate the profiling.
MacDonald informa.
seabed layers is a The equipment
seismic survey using selected for the
reflected acoustic sub-bottom survey
signals to create a was an Applied
two-dimensional Acoustics’ CSP-D
(2D) ‘picture’ or power supply, a
sub-bottom profile Squid 2000 sparker
which is used to array, CSR’s 12
map the geological channel streamer
boundaries. with Geode data
In the summer of logger. The data
2008, when there Fig. 2. The CSP-D seismic power source operates with logger was
was little sea-ice both boomer and sparker sound sources. controlled by a
present, work was Photograph: Geological Survey of Canada (GSC). shoot-on-distance
➠
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