Abstract: Systems and methods to determine a deghosted wavefield are described. In one aspect, the method computationally transforms recorded wavefield data from the space-time domain to a spectral domain and computationally deghosts the wavefield data in the wavenumber-frequency domain based on iterative minimization of a cost functional. The deghosted wavefield data may be transformed from the spectral domain back to the space-time domain and stored.

Abstract: Seismic data recorded in a marine streamer are obtained, sorted as a common receiver gather. A complex Laplace frequency parameter is used to transform the seismic data from a space-time domain to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a source deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide source deghosted seismic data, which is useful for imaging the earth's subsurface.

Abstract: A method is disclosed for deghosting and water surface multiple reflection attenuation in marine seismic data. The method includes decomposing data acquired at two water depths with sensors that measure the same parameter into upgoing and downgoing wavefield components. The decomposing includes, in one embodiment, transforming the data into the spatial Fourier domain and separating the upgoing and downgoing wavefield components in the transformed data. A substantially multiple-free wavefield is then determined from the decomposed wavefield components.

Abstract: Computational systems and methods for deghosting marine seismic streamer data using cost-functional minimization are disclosed. In one aspect, the method computationally transforms recorded wavefield data from the space-time domain to a wavenumber-frequency domain and computationally deghosts the wavefield data in the wavenumber-frequency domain. The deghosted wavefield data may then computationally transformed from the wavenumber-frequency domain back to the space-time domain and stored. The computational methods include iterative minimization of a cost functional in the wavenumber-frequency domain.

Abstract: Seismic data recorded in a marine streamer are obtained, sorted as a common receiver gather. A complex Laplace frequency parameter is used to transform the seismic data from a space-time domain to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a source deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide source deghosted seismic data, which is useful for imaging the earth's subsurface.

Abstract: Seismic data recorded in a marine streamer are obtained, with the seismic data being representative of characteristics of subsurface earth formations and acquired by deployment of a plurality of seismic receivers overlying an area of the subsurface earth formations to be evaluated, the seismic receivers generating at least one of an electrical and optical signal in response to seismic energy. A complex Laplace frequency parameter is used to transform the seismic data from a space-time domain to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide deghosted seismic data, which is useful for imaging the earth's subsurface.

Abstract: Seismic data are obtained for each seismic source activation in a marine streamer and for each frequency, after being transformed to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide deghosted seismic data.

Abstract: Seismic data recorded in a marine streamer are obtained, sorted as a common receiver gather. A complex Laplace frequency parameter is used to transform the seismic data from a space-time domain to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a source deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide source deghosted seismic data, which is useful for imaging the earth's subsurface.

Abstract: Seismic data recorded in a marine streamer are obtained, with the seismic data being representative of characteristics of subsurface earth formations and acquired by deployment of a plurality of seismic receivers overlying an area of the subsurface earth formations to be evaluated, the seismic receivers generating at least one of an electrical and optical signal in response to seismic energy. A complex Laplace frequency parameter is used to transform the seismic data from a space-time domain to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide deghosted seismic data, which is useful for imaging the earth's subsurface.

Abstract: A method is disclosed for deghosting and water surface multiple reflection attenuation in marine seismic data. The method includes decomposing data acquired at two water depths with sensors that measure the same parameter into upgoing and downgoing wavefield components. The decomposing includes, in one embodiment, transforming the data into the spatial Fourier domain and separating the upgoing and downgoing wavefield components in the transformed data. A substantially multiple-free wavefield is then determined from the decomposed wavefield components.

Abstract: A method is disclosed for deghosting and water surface multiple reflection attenuation in marine seismic data. The method includes decomposing data acquired at two water depths with sensors that measure the same parameter into upgoing and downgoing wavefield components. The decomposing includes, in one embodiment, transforming the data into the spatial Fourier domain and separating the upgoing and downgoing wavefield components in the transformed data. A substantially multiple-free wavefield is then determined from the decomposed wavefield components.

Abstract: Seismic data are obtained for each seismic source activation in a marine streamer and for each frequency, after being transformed to a spectral domain. An iterative conjugate gradient scheme, using a physically-based preconditioner, is applied to the transformed seismic data, to provide a least squares solution to a normal set of equations for a deghosting system of equations. The solution is inverse-transformed back to a space-time domain to provide deghosted seismic data.

Abstract: A method is disclosed for deghosting seismic data. The data include measurements of a vertical component of particle motion and pressure. The measurements are substantially collocated and made at a plurality of spaced apart positions. The method includes transforming the data into the spatial frequency domain, and separating upgoing and downgoing wavefield components of the transformed data. Water surface multiples may also be removed by decomposing the signals made at a plurality of seismic energy source locations into upgoing and downgoing wavefields.

Abstract: In one embodiment the invention comprises a method for receiving an acoustic wavefield beneath the surface of the water in which at least a portion of an acoustic wavefield is received at a first position, at least a portion of an acoustic wavefield is received at a second position, and at least a portion of an acoustic wavefield is received at a third position. The first position, the second position and the third position are triangularly positioned relative to one another. The first position is not directly above or below the second position or the third position, and the second position is not directly above or below the third position.

Abstract: A method is disclosed for controlling the quality of seismic data acquisition. The method includes generating a scattered acoustic wavefield and receiving at least a portion of the scattered wavefield. At least a portion of the received wavefield is substantially deghosting relatively near the acquisition site. The deghosting includes transforming the received scattered acoustic wavefield into the spatial frequency domain with respect to the in-line and cross-line directions, separating a ghost wavefield from the received wavefield and transforming the separated wavefield into the space-time domain. The quality of the substantially deghosted scattered acoustic wavefield below the surface of the water scattered acoustic wavefield is then evaluated.

Abstract: In one embodiment the invention comprises a method for receiving an acoustic wavefield beneath the surface of the water in which at least a portion of an acoustic wavefield is received at a first position, at least a portion of an acoustic wavefield is received at a second position, and at least a portion of an acoustic wavefield is received at a third position. The first position, the second position and the third position are triangularly positioned relative to one another. The first position is not directly above or below the second position or the third position, and the second position is not directly above or below the third position.

Abstract: In one embodiment the invention comprises a system for controlling the quality of seismic data acquisition substantially near the acquisition site. A scattered acoustic wavefield is generated and at least a portion of the scattered acoustic wavefield is received. At least a portion of the scattered acoustic wavefield is substantially deghosted relatively near the acquisition site and the quality of the substantially deghosted scattered acoustic wavefield is evaluated.

Abstract: In one embodiment of the present invention, a method for processing a scattered acoustic wavefield is provided. The scattered acoustic wavefield is received by at least two receivers. These receivers are offset and located at approximately the same depth. The method comprises transforming the scattered acoustic wavefield to the frequency domain. The method also comprises transforming the scattered acoustic wavefield from the frequency domain to the spectral domain. The method also comprises deghosting the scattered acoustic wavefield in the spectral domain. The method further comprises transforming the substantially deghosted transformed acoustic wavefield to the space-time domain.

Abstract: In one embodiment of the present invention, a method for processing a scattered acoustic wavefield is provided. The scattered acoustic wavefield (230) is received by at least two receivers (201). These receivers (201) are offset (250) and located at approximately the same depth (205). The method comprises transforming (101) the scattered acoustic wavefield (230) to the frequency domain (101). The method also comprises transforming (105) the scattered acoustic wavefield (230) from the frequency domain to the spectral domain. The method also comprises deghosting (110) the scattered acoustic wavefield (230) in the spectral domain. The method further comprises transforming (115) the substantially deghosted transformed acoustic wavefield to the space-time domain.