Pgs Tensor, Inc.

Pgs Exploration (uk) Limited

Petroleum Geo-services (us), Inc

Joel G Starr

John Brittan

A method is disclosed for processing seismic data from concurrently recorded co-located pressure sensors and geophones. The seismic data are processed by first determining an upgoing wavefield and a downgoing wavefield in the seismic data. Adaptive subtraction is then applied to at least one of the upgoing wavefield and the downgoing wavefield to remove the noise from the signal. In alternative embodiments, the upgoing wavefield can be used as a noise model for the downgoing wavefield or the downgoing wavefield can be used as a noise model for the upgoing wavefield.

Method for processing dual sensor seismic data to attenuate noise

A method and system of amplitude spectra estimation for seismic data using up-going and down-going wavefields includes gathering up-going and down-going wavefields, separating the up-going and the down-going wavefields from each other and crosscorrelating the up-going wavefields and the down-going wavefields. From the result of the crosscorrelation of the up-going wavefields and the down-going wavefields, an estimate of the amplitude spectra in the frequency domain of the seismic data can be obtained. In this method for amplitude spectra estimation, the gathering may include or may be accomplished by providing pressure and particle velocity detectors to distinguish between the up-going and the down-going wavefields. Also, in this method for amplitude spectra estimation, the gathering may include measuring the down-going waves and the separating may include removing the down-going waves from the seismic data. In the alternative, this method for amplitude spectra estimation, the gathering may include measuring the up-going waves and the separating may include removing the up-going waves from the seismic data.

Amplitude spectra estimation

A method and system of dual wavefield reinforcement or increasing the contributions to each image point in the seismic image can be accomplished by aligning the upward traveling energy, U, and the downward traveling energy, D, and then summing U and D in the stacking process. A method of dual wavefield reinforcement includes receiving seismic data having both up going and down going wavefields. The up going wavefields are separated from the down going wavefields. Pre-NMO and post NMO statics for each of said up going and said down going wavefields are calculated. The determined pre-NMO static is applied to each of the up going and the down going wavefields. NMO/DMO stacking velocities for the seismic data on an up going wavefield floating datum is determined. Using a difference between the up going wavefield floating datum and the down going wavefield floating datum and the NMO/DMO stacking velocities for the seismic data on an up going wavefield floating datum the NMO/DMO stacking velocities for the seismic data on a down going wavefield floating datum can be determined. The NMO/DMO stacking velocities for the seismic data on the up going wavefield floating datum and the down going wavefield floating datum is applied. The determined post NMO statics are applied to bring each of the up going and the down going wavefields to the final datum. The up going and the down going wavefields are summed to provide dual wavefield reinforcement.

Method of dual wavefield reinforcement

Processes are described for providing a data set useful for performing analysis of reflection attribute variation among traces in a window of three-dimensional seismic data, wherein the traces have a reflection point assigned thereto and wherein the traces represent recordings from shot-receiver pairs having various azimuth angles. According to one embodiment, the process comprises: assigning an offset value to a plurality of traces; fitting a substantially conical surface having a major and a minor axis to the data of the traces within the window, wherein: the major axis of the cone represents the azimuth direction having the lowest variation in the reflection attribute, and the minor axis of the cone represents the azimuth direction having the highest variation in the reflection attribute; assigning a coordinate set to the surface, wherein the coordinate set is related to a survey geometry of the data; and comparing the reflection attribute variation as a function of offset and azimuth.

Method of creating common-offset/common-azimuth gathers in 3-D seismic

A method for eliminating the influence of multiple reflections in seismic data by determining an up going and down going vector wave-field from the vector wave-field, determining a product of the free surface refection coefficient and the down going vector wave-field, and adding the product to the up going vector wave-field. Also provided is a method for eliminating the effects of receiver coupling from seismic data taken in a survey by describing a first cross-equalization filter as a function of the reverberation period, describing a second cross equalization filter as a function of the seismic data, deriving an inverse coupling filter as a function of the first cross-equalization filter and the second-equalization filter, and applying the coupling filter to the seismic data.

Method of reverberation removal from seismic data and removal of dual

A method for eliminating the influence of multiple reflections in seismic data by determining an up going and down going vector wave-field from the vector wave-field, determining a product of the free surface reflection coefficient and the down going vector wavefield, and adding the product to the up going vector wave-field. Also provided is a method for eliminating the effects of receiver coupling from seismic data taken in a survey by describing a first cross-equalization filter as a function of the reverberation period, describing a second cross-equalization filter as a function of the seismic data, describing an inverse coupling filter as a function of the first cross-equalization filter and the second-equalization filter, and applying the coupling filter to the seismic data.

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Richmond, TX, United States of America

Joel G Starr