CGGVeritas Wide-Azimuth Technology Represents Seismic Shift in Gulf of Mexico

Houston, September 24, 2007

In an industry where the pace for new acquisition technology is often slow, the rapid acceptance of marine wide-azimuth towed streamer acquisition methods as the new standard in deep water Gulf of Mexico represents an astonishing shift. In the few years since the early wide-azimuth acquisition efforts, it has become apparent that wide-azimuth data is providing superior sub-salt images compared to what was possible with conventional narrow-azimuth towed streamer data.

Early on, the promise of wide-azimuth methods led CGGVeritas to develop its capabilities. “We knew that if we could record more azimuths at longer offsets, and more of the full spectrum of the wavefield rather than only sampling a narrow portion of it, then we could achieve a quantum leap forward in our ability to illuminate the reservoir” explains Bruce Ver West, Technical Advisor & Imaging Director, Western Hemisphere. This preparation bore fruit with the award of the first ever wide-azimuth towed streamer acquisition project in 2004.

The operational complexities of wide-azimuth acquisition are enormous due to the number of vessels involved, often working in obstructed areas. It was clear from the onset that the acquisition of wide-azimuth marine data would require new methods and tools. An intense process of adaptation and innovation led to a new generation of robust, multi-vessel navigation and communication networks, comprehensive wide-azimuth QA/QC procedures and HSE optimization.

The first marine wide-azimuth project was followed up with two successive proprietary projects, building on our experience. “As the preliminary images from early wide-azimuth acquisition efforts were presented at various technical meetings and workshops, it quickly became apparent that wide-azimuth data were providing superior sub-salt images compared to conventional narrow-azimuth towed streamer data” recalls Phil Fontana, Geophysical Manager, Marine Acquisition. “With that in mind, we looked for ways of reducing the considerable acquisition efforts applied to field development programs while maintaining most of the imaging uplift from the wide-azimuth technique.”

The motivating objective for designing technically viable, cost-effective “sparse” wide-azimuth towed streamer acquisition methods is the ability to apply the technique over large areas. This provides a valuable tool in the exploration for deep water sub-salt projects, not just in the Gulf of Mexico but worldwide. The results of our extensive modeling and data analysis allowed us to optimize the X-WAZ*method which we are applying in our current Walker Ridge Wide-Azimuth Project. This project, the largest yet undertaken in the Gulf of Mexico, delivers the advantage of wide-azimuth to exploration and offers the flexibility to efficiently infill with D-WAZ**, to produce a high-density data set for field development. Two areas centered on recent lower Miocene discoveries have already been contracted for high-density, D-WAZ surveys.

Luc Schlumberger, Senior Vice President, Data Library, explains the dramatic shift to wide-azimuth in the Gulf of Mexico. “The large number of deepwater blocks available in the coming years and the challenges of developing complex, sub-salt fields have combined to create a strong demand for wide-azimuth data in the Gulf of Mexico. Clients are looking for programs based on solid design, the capacity and experience to deliver high-quality acquisition and a demonstrated ability to process the data, extracting the maximum uplift from wide-azimuth. We are mobilizing a second multi-vessel crew to start a large D-WAZ program in Garden Banks before the end of the year. Our projects have been well received by the industry and have reached a high level of pre-funding. We intend to expand our offer of high-quality wide-azimuth data over the Central Gulf area, acquiring more than 2,500 OCS blocks over the next 18 months.”

To attain the full benefits of wide azimuth data and to handle the increased data volume, the time-tested processing and imaging tools for the conventional, narrow-azimuth data have to be enhanced for robust wide-azimuth data. At CGGVeritas, a multi-disciplinary team consisting of researchers, software engineers, and processing and imaging specialists has been working diligently since 2005 to meet this challenge. To date, our team has processed several wide-azimuth datasets from the deepwater Gulf of Mexico with our new suite of wide-azimuth processing and imaging tools including data regularization, 3D SRME and tomography, as well as beam migration, one-way wave-equation migration and reverse time migration. The resulting images are highly acclaimed.

These outstanding tools are now being applied to wide-azimuth data currently being acquired in our Walker Ridge survey in the Gulf of Mexico. The initial results at the Jack discovery in Walker Ridge are astounding. According to Jerry Young, Senior VP, US Imaging for CGGVeritas, “…with a more uniform sub-salt illumination and better noise and multiple cancellation, the lower Tertiary Wilcox reservoir in Jack is clearly resolved on the fast-track wave-equation volume of the Walker Ridge wide-azimuth data. We expect the images to be further improved with the application of wide-azimuth 3D SRME, tomography and other advanced imaging algorithms.”

We have entered an exciting new era in geophysics. We look forward to sharing our advances in wide-azimuth acquisition and processing with our clients at the SEG.

* X-WAZ is an integrated suite of acquisition and processing methods and tools developed by CGGVeritas for optimum wide-azimuth exploration objectives.

**D-WAZ is an integrated suite of acquisition and processing methods and tools developed by CGGVeritas for extending the X-WAZ data to appraisal and development objectives.