| 摘要 |
An improved method and apparatus for gathering seismic data in a region covered by a body of water. Gas bubbles are formed in a zone of water adjacent a streamer containing hydrophones to form an acoustic lens for refracting acoustic waves which have reflected from the sea floor or subfloor geologic structures. This zone reduces the amount of noise at the hydrophones due to multiple reflections of sound between the water surface and floor. In the preferred embodiment, a pair of perforated gas dispensing tubes are towed from a seismic vessel. The tubes are maintained in a fixed position relative to the streamer generally above and on opposite sides of the streamer by a pair of paravanes, one attached to each tube. A gas compressing means aboard the vessel supplies gas to the tubes. The gas then escapes through the perforations in the tubes to form the zone. |
