Offshore seismic acquisition for high-resolution purposes

Abstract

The paper shows how high-resolutian seismic data can be acquired in the shallow part af a gea!ogical seetion, using a vessel equipped for eonventianal deepwater seismic exploration. It also presents a method for acquiring bath types af data simultaneously. To achieve high-resolution, lhe intervals between hydrophone groups and temporal samplings were both redueed. Neither the lenght of the source array nor the nearoffset could be altered, however, without jeopardizing conventional seismic data, although in deep waters, these parameters are more reconcilable with high-resolution demands. Pop interval and streamer depth cannot be altered during a simultaneaus survey due to limitations af conventianal seismic equipment, but during an exclusively high-resolution survey they could be modified. In arder to test this idea, those parameters thal would not affect conventional seismics were duly adjusled and a seismic test fine was then acquired. It was thus possible to simulate data oblained in a simultaneous survey. A fine with sparker and analog recording system was acquired in almost the same position for comparison. Data obtained using the test method proved much superior to the analog line, thereby enhancing geological interpretation of the shallow part for engineering purposes.