f Structural interpretation of sparse 3D data from interactive picking of reflections on pre-stack gathers

ECORS has conducted an experimental 3D reflection survey on a 8 x 27 km² swath within the North Pyrenean thrust zone using a sparse 3D land acquisition grid. Each shot is recorded on 6 parallel geophone lines that cover an 8 x 12 km 2 surface. The interval between lines is 1600 m. Each line has 120 traces at 100 m interval. The shots are placed every 400 m along columns perpendicular to the lines in a split spread configuration. The interval between columns is 2000 m. This unconventional geometry has been designed to test the feasibility of deep 3D structural imaging of a large volume at a reasonable cost. It results in a theoretical bin size of 50 x 200 m² and a coverage of 18 in the central part of the swath.