Abstract

The interest for 3D seismic is growing. In order to gain all the information inherent in the 3D-data volume an extensive work on planning, acquisition, processing should be undertaken.

To optimize the acquisition parameters with respect to the actual geology in the area and operational aspects, several studies should be made, including tests on source arrays, aperture zone (for migration), line/CPD-distance, navigation, shooting direction etc.

In order to avoid delays and to optimize resources in a timesharing situation, detailed coordinating of rigs, boats and other noise sources are necessary.

A crucial part of the 3D data processing is migration and velocity analyses. In 3D seismic, migration represents probably the most important part of the processing sequence as compared to conventional 2D seismic.

Most commonly the data are migrated in two orthogonal directions (2 × 2D). Velocity analysis is an important aspect as velocities are the most sensitive input to the migration algorithm.

To day most of the 3D-processing is an "extended 2D processing". How to optimize the use of a 3D data volume will therefore be discussed.

Interpretation of 3D surveys has during the last years become an increasingly more important task for the seismic interpreter.

In order to assist the interpreter, Norsk Hydro installed in October 1983 an interactive 3D interpretation work station. A combined use of this station and traditional film displays has proved to be a powerful tool to improve the interpretation.

The work station involves extensive use of colour display techniques, seismic attribute techniques, quality control, easy interpretation update, map generation and numerous other facilities.