Arrow Prospectus - PGS

ARROW SEISMIC ASA – INITIAL PUBLIC OFFERING
7.2 OVERVIEW OF THE GLOBAL SEISMIC MARKET
7.2.1 Marine geophysical services
Planning a seismic survey and acquiring, processing and interpreting the seismic data are the various activities of
a seismic project. The data acquired from the surveys are then used to produce computer generated graphic cross
sections (2D) or three-dimensional images (3D) of the subsurface. Companies acquire marine seismic data both
on exclusive contract basis for customers, and for their own risk as multi client data for marketing on a nonexclusive
basis to customers (further described in section 7.2.2).
Conventional streamer operations involve the acquisition of marine seismic data by discharging a wave of
acoustic energy just below the water’s surface from one or more energy sources towed behind a survey vessel.
The wave travels through the water and subsurface earth, with part of it being reflected back at rock layer
boundaries. The reflections are then detected by hydrophones contained in the towed streamers, converted into
digital data, and transmitted to a recording unit onboard the survey vessel. Before being put into a processing
system, the data is analysed for quality control purposes, enabling production of subsurface images.
A 2D marine seismic survey is typically produced by a survey vessel towing a single streamer and one energy
source. The data acquired from such a survey will generally represent a vertical cross-section along the line
tracked by the streamer. The concept used to acquire 3D data is similar. A vessel will tow multiple streamers to
produce a combination of parallel 2D cross-sectional data which can be processed to produce a 3D image of
subsurface strata. Sophisticated navigation equipment, permitting constant and precise determination of the
positions of streamers and energy sources during shooting, is needed for such data acquisitions.
A fourth dimension, evolved over time, is used to efficiently determine the changes occurring in the reservoir as
a result of hydrocarbon production or injection of water or gas into the reservoir by comparing the repeated
datasets. Time-lapse or 4D seismic involves comparing the results of 3D seismic surveys repeated at
considerable time intervals (e.g. before a field starts producing versus various production stages).
Adding to the conventional techniques, various seabed seismic operations are being used. Such methods are
more precise, as they are conducted by laying out permanent or mobile cable systems, or deployment of
individual nodes in grid patterns. Data collection takes place by multi components, 4C (pressure waves in 3
dimensions (x, y, z) and shear waves in one dimension). The cable systems are connected to the oil installation
or to a buoy. 2D or 3D vessels may be used as source vessels; in that case 2D vessels will normally be preferred
as they are less costly. Multi component seabed operations will usually only be performed where conventional
techniques are not possible or economically feasible due to access limitations, as streamer analyses are cheaper
and new seismic methods contribute to a closing gap on quality.
In addition, different methods of electro magnetic surveying (“EM”) are evolving. While seismic surveying
(using acoustic energy) can be used to find reservoirs deep below ground, it cannot always provide good
information on what kind of liquids they contain. EM has the unique feature of being able to, at a relatively high
degree of certainty, distinguish between hydrocarbon filled and water filled reservoirs in deepwater areas. The
two are separated by measuring subsurface resistivity, as hydrocarbon filled reservoirs typically have high
resistivity compared to shale or water filled reservoirs. EM contributes to reducing the uncertainty element of
exploration by further analyzing reservoirs detected by seismic surveys. EM has been tested in water depths from
110 to 3,100 metres and is most viable in offshore areas such as West-Africa, Brazil, South-East Asia, the
Norwegian Sea and in the Gulf of Mexico. Work is now under way to reduce the noise – or interference –
experienced by the signals in shallower waters, which would significantly extend the area of application for EM.
7.2.2 Contract work vs. multi-client work
The seismic industry operates with two types of business models – contract (proprietary) and multi-client data
acquisition. Proprietary contract data is acquired based upon a request from one specific customer and the
seismic data is exclusive for that customer. Multi-client data acquisition is on the other hand mostly initiated by
the seismic company itself with the aim to licence the data to multiple customers on a non-exclusive basis. The
seismic companies normally require a certain percentage of pre-funding before commencing multi-client data
acquisition.
One distinct difference between contract and multi-client acquisition is the risk with multi-client of not being
able to licence the data to other customers, compared to contract work where the company is guaranteed
predetermined revenue.
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