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New Directions for Marine Three-Dimensional Surveys

Javaid A. Durrani, William S. French, Lynn B. Comeaux

In the late 1960s and early 1970s there were severe constraints on how a marine three-dimensional (3-D) seismic reflection survey could be designed. Streamer location techniques were almost nonexistent, and seismic data-processing procedures were developed only for two-dimensional (2-D) surveys. For these reasons and others, 3-D surveys were designed as a collection of parallel 2-D seismic lines. Geologic considerations had a minimal impact because 3-D surveys were designed with the concept of dip direction and strike direction. As survey sizes grew, this simple geologic picture broke down.

Modern 3-D data processing systems and modern acquisition technology place fewer constraints on the design of 3-D surveys. We should exploit this new freedom where geology and straight lines are not compatible or where costs can be significantly reduced.

Successful marine 3-D surveys have been shot using parallel 2-D lines, crossed grids of parallel 2-D lines, collections of randomly oriented 2-D lines, and as a series of overlapping circular shot lines. A 3-D seismic survey was recently conducted over a salt dome by shooting a continuous series of concentric circles.

All 3-D methods seem to have both advantages and shortcomings. The more we learn about and use different techniques, the more we realize that our first ideas, such as considering a 3-D survey as a collection of parallel 2-D lines, may not necessarily be the best ideas.

AAPG Search and Discovery Article #91035©1988 AAPG-SEPM-SEG Pacific Sections and SPWLA Annual Convention, Santa Barbara, California, 17-19 April 1988.