When can a new exploration technology be considered to have resulted in a fully fledged industry? Is the answer a measure of turnover? Is it when explorationists have to justify not using the technology? Perhaps it is when the ‘big-three’ seismic companies are compelled to add the technology to their portfolios.
Whatever your criterion, deep electromagetic (EM) imaging, which uses EM energy to find hydrocarbons without drilling wells, has clearly become a major industry in its own right. Its much older sister industry, seismic surveying, has been the cornerstone for exploration decisions since modern-day oil exploration began. However, seismic techniques have limited ability to successfully predict the location of hydrocarbons when used in isolation, which is one reason why offshore exploration drilling hit rates are less than one in four.

Seismic methods

The traditional exploration workflow relies on indirect evidence to locate hydrocarbons, and seismic methods are mainly sensitive to rock structures and not to the fluids within them. In contrast, EM methods are very sensitive to reservoir fluids and can indicate hydrocarbons directly.
Naturally, the first popular use of EM imaging in the oil industry was to test, before drilling, whether the potential reservoir structures (prospects) identified from seismic data actually contained oil. This significantly reduced exploration drilling risks and avoided many costly dry wells.

Evidence of hydrocarbons

More recently, new applications of EM imaging have extended its use to acting like a divining rod to search for direct evidence of hydrocarbons before performing extensive seismic surveys or bidding for new acreage in licensing rounds. This is particularly valuable in frontier regions because it enables costly exploration resources to be targeted on the most promising areas, and it accelerates the delivery of higher-grade prospects and, ultimately, more discoveries.
Applications beyond exploration are also being pursued. Scientists and engineers are developing methods and technology to use EM imaging for field appraisal, advancing field development plans and even reservoir monitoring on mature assets to help optimise production and recovery.
Fewer than 10 years have passed since the idea behind the technology was conceived, and it is only five years since the first commercial survey was performed, and yet the usually conservative exploration community has embraced EM imaging.
During the latter half of 2007, interest in EM technology intensified and culminated in a frenzy of merger and acquisition activities, as smaller EM companies and the big-three seismic players have scrambled to catch up with the market leader and pioneer of the technique, Electromagnetic Geoservices (EMGS).

Invention and development

It is common belief that Thomas Edison invented the light bulb in 1879. However, several light bulbs were demonstrated before Edison’s.
Similarly, James Watt did not invent
the steam engine in 1769. He greatly improved its efficiency, but the first steam engine had been designed almost 100 years previously. This story repeats itself throughout history, with the pioneers of a technology frequently being left behind by the wave of developers.
However, offshore EM imaging, also known as seabed logging, is unusual because the people who invented the technology continue to work at the forefront of its development and commercialisation.
Terje Eidesmo and Svein Ellingsrud, who went on to form EMGS, first had the idea of using a powerful EM source to find offshore hydrocarbons in 1997 while working for Statoil.
They performed modelling work and scaled experiments, and then, in 2000, ran the first full-scale field trial, work for which they were recently awarded the Society of Exploration Geophysicists’ prestigious Virgil Kauffman Gold Medal.
In November 2002, EMGS conducted the world's first commercial offshore EM survey over Ormen Lange field in the North Sea. Since then, the company has performed over 300 surveys, logged more than 40000km of the ocean floor (greater than the Earth’s circumference) and deployed over 11000 seabed EM receivers (Fig.1).
The reason for such rapid growth is simple: the technology works. Offshore exploration drilling success rates have historically been around one in four. By contrast, EMGS’ surveys have correctly predicted the outcome in more than 90 per cent of the cases where the company has drilling results.
Another reason for the technology’s success is that EM data is independent of, but fits well with, seismic data. The first commercial depth migration of EM data, performed by EMGS in 2004, was a real milestone. It meant that EM data could be independently correlated with seismic and other geological information (Fig.2).

Big-three adoption

Unsurprisingly, given that EM surveying can directly test for the presence of commercial-scale offshore hydrocarbons and can help to avoid the drilling of dry wells, the technology has been rapidly adopted. Indeed, the big-three seismic companies are all climbing on board by acquiring or joining up with smaller
EM-surveying companies.
Schlumberger bought AOA Geomarine Operations in 2004; Petroleum Geo-Services swallowed up MTEM Ltd in June 2007; and CGG Veritas purchased a stake in Offshore Hydrocarbon Mapping a month later.
The scramble to catch up with market leader EMGS is a sure sign that the offshore EM-surveying industry has come of age.
In March 2007, EMGS floated on the Oslo Stock Exchange. Its shares were 13 times oversubscribed, which is another indication of the interest and belief in the industry.
More recently, in November 2007, to broaden the EMGS portfolio and extend further the operating range of its advanced EM-imaging systems, the company bought 50percent of EM-specialist KMS Technologies and acquired the rights to its proprietary time-domain EM technology.

Exploring with surgical precision

Scanning is a growing application for EM surveying that can rapidly identify leads in large areas, regardless of their seismic expressions (Fig.3). Scanning surveys enable costly exploration resources to be targeted on the most promising areas, and they accelerate the delivery of higher-grade prospects and, ultimately, more discoveries where there is oil to be found.
Scanning is particularly well suited to exploration in environmentally sensitive frontier regions. EM imaging has an inherently small environmental footprint; the source is harmless to sea mammals and the sensor anchors are made using a proprietary material that degrades to environmentally benign products (Fig.4).
Also, similarly to the way that medical scans enable surgeons to pinpoint problem areas before operating, EM scanning enables subsequent exploration investments and activities to be guided with almost surgical precision to more prospective areas, thereby improving exploration efficiency and reducing funding costs.
The scale and effectiveness of scanning surveys are driving new multi-client business models and the development of new enabling modelling technologies. Scanning has been predicted to become the first-look method of choice for finding hydrocarbons in frontier areas; so, it is little wonder that the big-three seismic companies want a piece of the action.

A solid foundation

All the super-major and many of the independent and national oil companies have commissioned offshore EM
surveys. This widespread adoption has
been described as ‘…a remarkable achievement for a young technology, given the oil industry’s notorious reluctance to embrace innovation’ (Offshore Engineer, August 2007, p 22).
EMGS continues to work with government agencies, major resource holders and all the leading energy companies. It has offices across the world and operates the industry’s largest survey fleet, with five vessels and two more purpose-built vessels planned for 2008.
These vessels and EMGS’ on- and offshore teams are helping operators to enhance their exploration performance by reducing the number of dry wells, enabling new discoveries and, ultimately, giving them a competitive edge.

Integration techniques

EM surveys can now be acquired in 3D, and the active research and development department at EMGS is constantly developing the survey equipment and the modelling and integration techniques.
In its Virgil Kaufmann Gold Medal award citation for the original inventors of the technique, the Society of Exploration Geophysicists stated: “This pioneering work spawned a new service industry,” and that would certainly seem to be the case, judging by the evidence presented here.
It is an exciting time to be in the fast-moving EM industry. Who knows what the next decade will bring?l

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Ken Feather is vice president of marketing with Electromagnetic Geoservices (EMGS), Trondheim, Norway. www.emgs.com