Computing device, computer instructions and method for correcting an image, of a surveyed surface, due to a free-surface reflection. The method includes calculating a free surface reflection operator for a seismic source displaced in water based on a position of the source, and an air-water interface datum; receiving recorded seismic data d recorded with seismic sensors (r), wherein the recorded seismic data is associated with a pressure and/or a particle motion produced by a seismic wave in earth; correcting the recorded seismic data d based on the free surface reflection operator to obtain transformed seismic data; and generating an image of the surveyed subsurface, based on the transformed seismic data, wherein the image is indicative of various layers of the earth. The free surface reflection operator varies while a source signal is being emitted by the source.

Provided is a method for swell effect and mis-tie correction in high-resolution marine seismic data using multi-beam echo sounder data, and more particularly, a method for swell effect and mis-tie correction in high-resolution marine seismic data using multi-beam echo sounder data capable of acquiring the high-resolution marine seismic data having the swell effect and the mis-tie effectively corrected by using the multi-beam echo sounder data including water depth data of a sea-bottom having high precision.

Effects of time variability of water velocities in seismic surveys are addressed. Traveltime discontinuities in the input seismic data which are associated with the time-variable water velocities are determined. The input seismic data is transformed from a data space that contains the traveltime discontinuities into a model space which does not contain the traveltime discontinuities. Then the transformed seismic data is reverse transformed from the model space back into the data space.

Techniques are disclosed relating to the determination of a warping attribute related to a difference between an up-going pressure wavefield and a down-going pressure wavefield received from a seismic data acquisition system. The warping attribute is used to determine a pseudo up-going or down-going pressure wavefield. The pseudo pressure wavefield is used to generate a modified record of geophysical data, which is stored in a non-transitory memory medium as a geophysical data product.

Computing device, computer instructions and method for correcting an image, of a surveyed surface, due to a free-surface reflection. The method includes calculating a free surface reflection operator for a seismic source displaced in water based on a position of the source, and an air-water interface datum; receiving recorded seismic data d recorded with seismic sensors (r), wherein the recorded seismic data is associated with a pressure and/or a particle motion produced by a seismic wave in earth; correcting the recorded seismic data d based on the free surface reflection operator to obtain transformed seismic data; and generating an image of the surveyed subsurface, based on the transformed seismic data, wherein the image is indicative of various layers of the earth. The free surface reflection operator varies while a source signal is being emitted by the source.

A method comprising for deghosting seismic data is disclosed. The method includes the steps of acquiring seismic data by conducting a survey of a subsurface area of interest wherein the seismic data includes ghost data and estimating a time-varying wave height above the subsurface area of interest during at least a portion of the survey, wherein the estimation of the wave height is based at least in part on a remote measurement of the wave height during the survey. The estimated time-varying wave height is used to characterize the ghost data and deghost the seismic data based at least in part on the characterized ghost data.

Effects of time variability of water velocities in seismic surveys are addressed. Traveltime discontinuities in the input seismic data which are associated with the time-variable water velocities are determined. The input seismic data is transformed from a data space that contains the traveltime discontinuities into a model space which does not contain the traveltime discontinuities. Then the transformed seismic data is reverse transformed from the model space back into the data space.

Techniques are disclosed relating to the determination of a warping attribute related to a difference between an up-going pressure wavefield and a down-going pressure wavefield received from a seismic data acquisition system. The warping attribute is used to determine a pseudo up-going or down-going pressure wavefield. The pseudo pressure wavefield is used to generate a modified record of geophysical data, which is stored in a non-transitory memory medium as a geophysical data product.

At least some of the example embodiments are methods including: performing Normal MoveOut (NMO) correction on a first Common Depth Point (CDP) gather, the NMO correction based on a reference velocity of sound in water, the NMO correction creates first NMO data with a plurality of traces; selecting a first estimated velocity that makes travel time represented in the traces substantially the same; calculating a zero-offset time shift that represents a difference in travel time as between the reference velocity and the first estimated velocity at a zero-offset trace; performing NMO correction on the first CDP gather based on a final estimated velocity to create second NMO data; adding the zero-offset time shift to each trace of the second NMO data; and then performing reverse NMO correction on the second NMO data to create corrected data.

A method comprising for deghosting seismic data is disclosed. The method includes the steps of acquiring seismic data by conducting a survey of a subsurface area of interest wherein the seismic data includes ghost data and estimating a time-varying wave height above the subsurface area of interest during at least a portion of the survey, wherein the estimation of the wave height is based at least in part on a remote measurement of the wave height during the survey. The estimated time-varying wave height is used to characterize the ghost data and deghost the seismic data based at least in part on the characterized ghost data.