Multi-directional seismic exploration methods on navigable water

摘要

A number of seismic detectors are located in a two-dimensional array on the surface of the earth, either on land or at sea. One or more seismic disturbances are produced in the vicinity of the seismic detectors at points located to produce sampling of various subsurface reflection points to form one or more two-dimensional areas of coverage. For each seismic disturbance, the subsurface reflections thereof received by the various seismic detectors are recorded. In some embodiments, the seismic disturbances are produced at points located to produce multi-directional sampling of each of various subsurface reflection points and recordings for different ones of the seismic disturbances are combined to produce stacked recordings wherein multi-directional reflections from common subsurface points are added. On navigable water the multi-directional sampling is conducted by traversing a region to be surveyed with two vessels on generally parallel courses each towing a string of hydrophones, and alternately creating seismic disturbances in the water adjacent each vessel to thereby sample a plurality a reflecting points located along a line which tracks the planned survey line well notwithstanding deviations in the courses of the vessels and hydrophones caused by water currents and navigational errors.