Patent ID: 8063642

Claim:
A method for electromagnetic exploration of subsurface formations below a body of water, comprising: imparting a first electromagnetic signal into the subsurface formations from a first location suspended above the bottom of the body of water; imparting a second electromagnetic signal into the formations from a second location substantially contemporaneously with imparting the first electromagnetic signal, the first and second electromagnetic signals substantially uncorrelated with each other; detecting a combined electromagnetic response of the formations to the first and second imparted electromagnetic signals at a third location; and determining a response of the formations to each of the first and the second imparted signals from the detected response, wherein determining formation response to the first electromagnetic signal comprises: (a) deconvolving the detected signal using the first electromagnetic signal; (b) estimating the formation response to the first electromagnetic signal using the deconvolved detected signal; (c) convolving the estimated formation response from (b) with the first electromagnetic signal; and (d) subtracting a result of the convolution of the estimated formation response with the first electromagnetic signal from the detected signal.