20 controlled source electromagnetic resonance
Adapt and innovate to survive
impact of the financial crisis
Dr Neil Grosse looks at how the financial
decisions on drilling. However, it is a technology in its
crisis that has impacted all areas of the
infancy and the cost of acquisition of EM data is high
compared to conventional seismic. Therefore, in these
global economy, not least the seismic and times of relatively low oil prices it is one of the areas
hydrographic industry.
which have suffered a notable drop in investment.
At the same time industry projections were indicating
C
ompanies will have to adapt and innovate to a major shortfall in capacity of towed streamer seismic
prosper in this challenging new environment and in particular multi-streamer 3D vessels. Many
caused by the financial crisis within the companies had embarked on ambitious new-build
global economy and it is worth examining programmes and a number of these vessels have
how these environmental pressures will influence the come on-stream in the last 12 months compounding
focus of offshore activity. the overcapacity that has now engulfed the market.
Up until 2008 Controlled Source Electromagnetic Hopefully, this surplus will be short-lived as confidence
(CSEM) surveying had experienced year-on-year growth. gradually returns to the industry.
This technique offers the prospect of direct detection
of hydrocarbons via their resistivity signature and has
Enhanced oil recovery
tremendous potential to reduce the risk when making In the current cautious climate the focus is very much on
enhanced oil recovery (EOR) from existing
fields. Even relatively modest improvements
of 5 per cent additional recovery can
equate to a major financial return and
this offers a relatively low risk investment
for companies that have already invested
heavily in developing fields and establishing
the infrastructure of rigs, pipelines, etc. Key
to this activity is 4D time lapse seismic and
4C multi-component seismic.
4D seismic aims to track changes in
reservoir properties over time, based on
subtle changes detected in periodically
acquired seismic datasets. There are
many variations on the method ranging
from towed streamer to permanent and
retrievable ocean bottom seismometers,
either cable (OBC) or nodes (OBN).
The repeatability of towed streamer
4D has been enhanced considerably by
recent improvements in streamer steering
technology which have significantly
reduced positioning errors. This is vital
as variations in source and receiver
positioning can generate differences in
the resultant seismic data of the same
order of magnitude as those caused by
changes in the state of the reservoir itself.
The new streamer technologies also
include single channel acquisition, and
recording of a broader bandwidth, both
at the high and low end of the spectrum,
which has enabled greater resolution of
Fig. 1. The Forsar Seismic PRM System. Image: Stingray Geophysical Limited target horizons.
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