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Leading edge imaging systems

15th April 2013

With global E&P budgets set to reach a record total of USD 644bn this year, operators will look to the latest and most efficient broadband subsurface imaging technologies to address exploration and development challenges

Leading edge imaging systems
Both WesternGeco and PGS have unveiled new broadband seismic techniques for enhanced imaging of complex subsurface geology

Global exploration and production this year is set to topple any previous spending records. According to the Barclays Global 2013 E&P Energy Spending Outlook released in December, investments in exploration plays will reach a new record of USD 644bn, up 7 per cent – USD 40bn – against 2012.

“These projections suggest our early look at 2013 spending levels may underestimate total spending levels,” Barclays says. Markets outside North America will be the main clusters of E&P capital, with exploration budgets claiming a bumper growth of 9 per cent to USD 460bn, Barclays stated after surveying over 300 oil and gas companies.

In the US, top 2012 E&P spender ExxonMobil will allocate USD 37bn a year for its exploration strategy, as part of its USD 185bn capital spending program through 2016, while Chevron will see a 17 per cent growth in its drilling and exploration program.

To the south in Brazil, Petrobras plans to spend USD 141.8bn in exploration and production activities alone in the next four years –, which equals more than half of the total USD 236.5bn in investments contemplated in its 2012-2016 business strategy plan.

Turning east to Australasia, spending this year is expected to grow by 11 per cent, led by PetroChina (11.5 per cent), Petronas (7.7 per cent) and Sinopec (14 per cent). China's biggest offshore oil and gas producer, CNOOC says it will increase its capital spending to USD 12-14bn in 2013, up from USD 9.2bn last year, with the company planning to drill 140 wells mostly offshore China.

If indeed significant E&P spending spurred by major projects, plans to drill new wells and the delivery of new offshore rigs is any indication of what one can expect in the seismic and geosciences sector, then this year may yet prove to be just as exciting to the latter. In effect, this would not seem controversial when one considers that 3D and 4D seismic surveying and data acquisition consistently rank among the most impactful areas on operators’ spending programs.

The surge in E&P spending will allow major marine seismic contractors such as the top five companies in the industry – CGG, WesternGeco, Petroleum Geo Services (PGS), Polarcus and Dolphin – to contemplate the addition of new and more advanced 3D seismic vessels to their fleet. However, such moves will have to be substantiated by proof that recent and upcoming seismic and data acquisition technologies are reliable, efficient and, as a result, will secure significant demand from oil and gas operators.

A new generation of imaging systems

Both Schlumberger subsidiary WesternGeco and PGS have unveiled new broadband seismic techniques for enhanced imaging of complex subsurface geology.

Western Geco’s IsoMetrix system was described as a “breakthrough technology” by Schlumberger when launched in June last year, largely by overcoming spatial wavenumber bandwidth issues which proved to be a limitation to previous marine seismic acquisition methods.

The IsoMetrix system uses multisensor MEMS (multicomponent, microelectromechanical system) technology and returns wavefield in 3D. The sensors measure acoustic pressure as well as vertical and crossline particle velocity and acceleration along the whole width of the frequency range. IsoMetrix is able to be towed deeper while delivering broadband data, an improvement on seismic streamers which usually rely on hydrophones to measure scalar pressure.

IsoMetrix enables high-resolution near-surface characterization, well integrity planning and 4D repeatability for improved exploration. In situ testing last year saw the system achieve a 12:1 crossline reconstruction ratio and produce a 6.25 m data grid from streamers 75 m apart.

“Through an extensive 10-year research and engineering program, we have developed a new category of seismic that not only includes the acquisition technology, but also the algorithms and workflows needed to manage such an unprecedented amount of data,” said Carel Hooykaas, president of WesternGeco. “The step change in imaging is as profound as was the move from X-rays to full 3D scans in the world of medicine,” he claims.

As major oil and gas discoveries become less common, companies turn to uncovering less obvious areas as well as reservoirs which may have been overlooked. Adding an electromagnetic data dimension to existing seismic capabilities – something which PGS has tried to develop since 2004 – can prove considerably useful in highlighting those prospects and guaranteeing a successful exploration project.

PGS’ EM survey technique relies on a towed electromagnetic streamer. The system works similarly to the seismic streamer and measures the electric field throughout its length. Data acquisition functions through the incorporation of dipole receiver pairs in the streamer, which is towed behind the survey vessel while an in-line dipole source is towed from the same vessel ahead of the EM streamer.

The EM source injects high current into the water between two large electrodes, creating an electric field which is measured along the streamer. The source provides up to 640 kAm, allows for RGPS positioning and can be towed 10 m below surface.

The bulk of the system’s construction is based on PGS seismic streamer technology. The streamer has custom acquisition telemetry, is suitable for operations in variable sea states and includes proprietary noise reduction systems.

PGS announced last year that multi-client data surveys had been successfully acquired in seven known fields with different geological settings. Operations throughout 2012 took place in water depths of 100-350 m with surveying target depths of 1,300-2,200 m and  production figures reportedly in excess of 110 vessel-km/day. This year, PGS is planning a minimum of three months of EM acquisitions in the North Sea and Barents Sea.

CGG and Fugro pave the way

Looking ahead, how the seismic sector takes shape will largely depend not simply on the outcome of exploration plays, but on how seismic technology operations develop throughout the year and, perhaps more importantly, on what new solutions R&D initiatives provide.

CGG and Fugro are expected to lead the way in this respect, following the former’s USD 1.2bn acquisition of Fugro’s geoscience division and the creation of a joint venture, Seabed Geosolutions which is 60 per cent owned by Fugro and 40 per cent by CGG.

For the Seabed Geosolutions joint venture, CGG will contribute its shallow water, ocean bottom cable and permanent reservoir monitoring services along with its ocean bottom node business, while Fugro also contributed the latter. It will be of great interest to witness how this partnership develops in terms of technology in 2013.

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