| 摘要 |
A seismic survey system includes winches 21,22 having winch cables 23,24 coupled to a source array 12 which is towed between lead-ins 17 attached to deflectors 16. A positioning system 29 (eg GPS, acoustic network, laser system) determines the current position of the array 12 and a controller 32 adjusts the winches 21,22 to modify the position of the array 12 to a desired crossline position. The winches exert a lateral force on the array 12, derived from the lead-ins. The winches may be on the tow vessel 11 or may be located in the sea attached to the lead-ins 17 (see figure 3). Alternatively a single capstan winch may be used (see figure 2). Optionally, by adjusting the gun cable winches to adjust the length of the gun cables, the inline position of the array may be controlled (see figure 8). The system allows the source array 12 to be located at a crossline position which is substantially identical to a position employed in a previous survey. |
