Quality-based steering methods and systems for 4D geophysical surveys

US8717845B2 · kind B2 · utility

Assignee

• PGS Geophysical AS · NO

Inventors

• Bengt Boberg · Singapore, SG
• Jon Falkenberg · Vikersund, NO
• Anders Mattsson · Oslo, NO

Key dates

• Filing date: Aug 24, 2011
• Grant date: May 6, 2014
• Expiry date: Sep 11, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G01V1/3817
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A survey method includes towing one or more sources and one or more streamers behind a vessel to acquire geophysical survey data. Steering signals are determined for at least one of: the one or more sources, the one or more streamers, and the vessel. The steering signals minimize an error function having parameters that include a measure of a cross-line position error and a measure of data quality. The cross-line position error may be measured as an offset of the sources or the receivers from their desired paths, or in some embodiments as an offset between midpoints for base survey traces and subsequent survey traces. Some embodiments may employ a maximum spatial cross-correlation coefficient between a newly acquired trace and one or more base survey traces as a data quality measure, while others may employ a time shift, a phase rotation, or a normalized root mean square error. Data quality may indicate sensor noise levels.