4D seismic involves repeated 3D seismic surveys carried out over a targeted reservoir to image the movement of hydrocarbon fluids. The results enable oil companies to more accurately focus their drilling and other measures to optimize production, a process which can net millions of dollars in additional recoverable reserves.
Last year Concept launched an R&D program with Shell Expro in the UK to find a way of ensuring that new surveys for 4D seismic analysis accurately repeated the original acquisition parameters. Studies showed that variations in factors such as survey geometry, weather, and tides could all introduce significant positional errors into the repeat surveys, and that Concept’s existing Reflex navigation and positioning data handling system for seismic operations could provide the basis for a solution.
Within weeks Concept was able to deliver to Shell Expro the technology and communications system to enable suspect areas of acquired data coverage to be reshot as ‘infill’ while the seismic vessel was still on station. The 4D repeatability analysis system was tested in the North Sea. Shell Expro's geophysicists onshore were able to make 'infill' decisions during a 4D seismic survey based on data analysis relayed to them by a secure Web services site.
Frans Smit, Operations Geophysicist, Shell Expro, said: 'Our relationship with Concept has allowed the fast track development and deployment of this technology. We are now able to make decisions allowing optimal infill during the actual acquisition phase of a 4D project.'
Alastair Hay, managing director, Concept Systems, said: '4D seismic is increasingly regarded by oil companies as the way forward for monitoring reservoir performance and maximizing output, but the survey data must be accurate if it is to be effective. We believe that our technology has tremendous potential to give oil companies genuine confidence in their survey data which may have been lacking in the past.'
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