Patent ID: 6236211
Filing Date: 2001-05-22
Classification: G01V

Abstract:
A method for detecting minerals and metal-containing materials which are located in and on a sea floor having a sea floor sediment and which exhibit an induced polarization response, said method comprising:trailing a streamer cable in the sea behind a ship, said cable having a free end and including at least one transmitter and at least two receivers disposed in spaced relation at said free end and comprising four electrodes arranged together in groups of three to form first and second dipole groups each including a shared electrode and a central reference electrode and said cable being trailed such that said free end and said at least two receivers are positioned in the sediment on the sea floor;towing said streamer cable back and forth along spaced paths in an expanding grid pattern to provide large area coverage of the sea floor;using said at least one transmitter to transmit an electrical current into the sediment of the sea floor;terminating the transmitting of said electrical current and using said at least two receivers to detect secondary signals produced by an induced polarization source located on or beneath the sea floor in response to said terminating of the electrical current; andprocessing said secondary signals using stacking and averaging of the secondary signals to determine measurement parameters characteristic of the source of the secondary signals.