GEOLOGY & GEOPHYSICS
Integrated EM, broadband solution
improves acquisition rate
Towed streamer system expands technology’s application range
In the current low oil price environment, oil companies are increasingly focused on acquiring higher quality subsurface data faster and more cost effectively. One can question what “cost-effective”
really means when it comes to improving the
chances of discovering commercial volumes
of hydrocarbons. Is it paying the lowest price
for a commoditized service, or is it more
accurately described as extracting and integrating every bit of subsurface information
within the limitations of the available exploration budget?
Maximizing value for money means employing the correct technology in the appropriate environment and thereby improving
chances of success.
Exploration managers must be confident
that geophysical technologies will provide
extra subsurface information that will have
a material impact on licensing, exploration,
and drilling decisions. To this end, PGS
conducts 3D controlled-source electromagnetic (CSEM) feasibility studies prior to acquisition, which provide oil companies with an
understanding of how towed streamer EM can assist in solving a
particular geophysical challenge.
For example, a large-scale 3D towed streamer EM campaign,
strongly supported by industry, was acquired during 2014-15. This
data has been used by companies during various stages of Norway’s
23rd licensing round, the results of which were announced in May,
with 10 new production licenses awarded to 13 companies. Further
evidence of the increasing value attached to EM technology can be
seen in the 2016 Awards in Predefined Areas round: 10 of the licenses
offered included some reference to EM in their work programs com-
pared to one in 2012 and none in both 2013 and 2014. Thus, 3D multi-
client EM data has assisted oil companies in decision-making prior to
and during recent license rounds offshore Norway.
The maximum value of CSEM data is extracted when interpreted
and integrated with seismic and other geophysical information.
From a simple co-rendering of seismic and resistivity data, to seismically guided inversion, and even reservoir level workflows such
as estimating hydrocarbon saturation and hydrocarbon volumes in
place, towed streamer EM data significantly improves subsurface
understanding prior to investment decisions being made. This improved understanding can provide oil companies with a competitive advantage when
it comes to bidding on acreage, drilling exploration wells, and even optimizing field development and production. Further, EM can
provide improved confidence in how explo-Joshua May
Map detailing the location of PGS’ multi-client CSEM data in the Barents Sea, shown in green, overlain with acreage awarded in Norway’s 23rd licensing round. (All images courtesy PGS)
Seismically guided inversion–resistivity
section produced from simultaneously
acquired GeoStreamer and EM data.