Abstract:

During the gas-hydrate investigation on the some China Sea, the method named “single source Single streamer semi-three dimension seismic survey” was used to get a satisfying 3D imaging of gas-hydrate mineral body. There are many factors influence the effect of 3D imaging, and streamer dynamic positioning precision is a most important and direct one. Based on a large amount of test data, the authors discussed the influence of compasses on the streamer dynamic positioning precision. And the results were accorded well with sea test data and domestic and overseas seismic data. This will provide a guiding significance for gas-hydrate semi-three dimension seismic survey. According to the result, and with a certain positioning error, the authors confirmed that a streamer array length of 2 400 meters (192 channels) could achieve higher dynamic positioning precision. From the drilling in this area in 2007, the gas-hydrate sample was first found in China. The accordant result of drilling with the seismic data confirmed that the positioning precision had reached a higher level on semi-three dimension seismic survey.

Key words: semi-three dimension seismic, dynamic positioning precision, network-three-nodes method, compass positioning precision, streamer feather