WesternGeco announced today an expansion of its multiclient wide-azimuth (WAZ) survey in the U.S. Gulf of Mexico as a result of underwriter demand for high-quality subsalt imaging and optimized data resolution.

The E-Octopus project is in its third phase of acquisition and WesternGeco will add a fourth phase in November 2007 with a fifth phase in early Q1 2008. These WAZ surveys offer the unique advantage of more precise base and edge of salt definition through the integration of magnetotellurics, gravity and Q-Marine* data through MMCI* multimeasurement constrained imaging.

"We are currently conducting targeted magnetotelluric surveying in the most challenging imaging areas for all phases of the E-Octopus program," said Aaron Gatt Floridia, vice president, WesternGeco Electromagnetics. "Previous pilot studies using marine magnetotellurics (MT) have successfully indicated salt thickness variation. Based on these results, we are offering the addition of integrated MT measurements as part of our WAZ service. This technology step-change and the project expansion will greatly improve the critical base salt and subsalt images required by our clients."

The E-Octopus project, the first multiclient wide-azimuth program in the Gulf of Mexico, commenced in July 2006. Since then, over 700 OCS blocks of wide-azimuth data have been acquired. The third phase of acquisition began in May 2007, which covers more than 450 OCS blocks of the highly prospective Green Canyon area in the Gulf of Mexico. To date, greater than 45% of the survey area has been acquired. In response to client demand, a second Q-vessel WAZ fleet will arrive in November 2007 to begin additional acquisition in the Gulf of Mexico.

WesternGeco has also developed the world’s first onboard prestack wave-extrapolation (WEM) depth migration in the third phase of E-Octopus through the use of its proprietary Q-Xpress* technique, providing quick-look migrated data volumes for interpretation, quality control, illumination and in-fill acquisition requirements. The final deliverables for these surveys will include the latest state-of-the-art technologies such as anisotropic multi-azimuthal tomography, wavefield extrapolation demultiple and shot domain WEM with angle gathers.