1. A method for oil and gas exploration in an underground formation covered by shallow water, the method comprising: acquiring seismic data related to the underground formation by deploying data acquisition equipment, generating seismic waves and detecting reflected seismic waves; reconstructing a 3D seafloor reflectivity image using the seismic data; evaluating a seismic wave equation using, as an input, said reconstructed 3D seafloor reflectivity image to determine surface multiples; subtracting said determined surface multiples from said seismic data to obtain surface multiples free seismic data; and generating an image of the underground formation based on the surface multiples free seismic data, the image being usable to evaluate whether oil and gas is present, wherein said step of reconstructing comprises: estimating a plurality of 1D prediction deconvolution operators with a group of short offset traces; migrating each of said plurality of estimated 1D prediction deconvolution operators to create a set of migrated 1D prediction deconvolution operators; accumulating said set of migrated 1D prediction deconvolution operators to create a set of 3D prediction deconvolution operators; and reconstructing said 3D seafloor reflectivity image within a geographical area of interest, GAI, using said set of 3D prediction deconvolution operators.