Scottish 4D seismic services company Reservoir Imaging Ltd (RIL) is working on the planning and quality control (QC) of wide-azimuth surveys, the emerging marine seismic data acquisition technique being employed to image complex geologies such Gulf of Mexico subsalt.
The Edinburgh-headquartered firm says it draws on its experience and expertise in ensuring 4D seismic reservoir monitoring accuracy to provide optimal positioning and QC for the large towed streamer spreads being deployed in wide-azimuth surveys.
Wide-azimuth surveys of the kind carried out by players such as Western Geco have source lines shot multiple times by source vessels, and these must be accurately plotted in the same way as the repeat lines in a 4D seismic survey.
A further challenge is the need for “feather-matching”, a process which ensures that the varying degrees of ocean turbulence affecting the seismic recording cables on each line recorded can be accurately accounted for in the seismic data acquired.
RIL has adapted and enhanced its Osprey suite of 4D survey QC technologies to deal with the complexities of wide-azimuth acquisition. The firm says its personnel in the field perform the data quality control with all outputs loaded into a GIS database. The QC system incorporates mapping, repeatability, coverage and documentation. Results are made available via a web-based GIS server which enables all the stakeholders to be involved in the decision-making process regarding the survey’s progress.
RIL MD Keith Watt said: “It was always apparent that wide-azimuth surveys presented many of the same positioning and QC issues we have been dealing with for major oil companies in their 4D survey projects. We are delighted that BP is the first client to apply the new technology and services on a live project.”
It was in January, 2008, that this 4D seismic software services consultancy was awarded major projects by Shell and BP for surveys in the North Sea. The company was tasked with advising on the implementation of all aspects of these 4D seismic surveys, from initial design and planning through to quality control, either on board the vessels or remotely from onshore.
RIL was formed in September, 2005, by a group of geoscientists who were all previously with Concept Systems and who specialise in 4D. The firm claims a growing client list, with projects in the North Sea, Gulf of Mexico, West Africa and South-east Asia.