Westerngeco L.l.p.

Ion Geophysical Corporation

Inova Gmbh

Western Atlas International, Inc.

Halliburton Company

Gary Arthur Sitton

Robert Ian Bloor

J MacDonald Smith

Frederick James Barr

Zeljko Jericevic

David Lee Nyland

Rainer Moerig

Theodore C Stieglitz

Ronald E Chambers

Josef Paffenholz

Frederick J Barr

Zelijko Jericevic

Marvin Glen Michael Decker

David L Nyland

A seismic information processing method and apparatus includes attenuating flexural wave noise information from seismic information. Flexural wave information removal includes receiving the seismic information using an information processing device interface, the seismic information having a plurality of directional components acquired using a multi-axis motion sensor coupled to ice floating on a body of water, the seismic information including desired seismic information and the flexural wave information. A noise model of the flexural wave information may be generated using at least one of the plurality of seismic information directional components using an information processing device. The noise model is improved using an adaptive correction filter, and the improved noise model is applied to at least one directional component of the received seismic information to attenuate the flexural wave information wave in the seismic information.

Flexural wave attenuation

Seismic acquisition systems are disclosed that allow contemporaneous seismic sources to be separated from a composite signal comprising two or more constituent seismic sources. In some embodiments, a representation of the composite signal may be developed that includes a noise contribution of undesired signals present in the composite signal. Additionally, an operator, referred to herein as an 'annihilator', may be developed such that it may be conditioned and inverted to minimize undesired noise contributions in the composite signal. This inversion may assist in recovering the constituent seismic sources from the composite signal. Furthermore, in some embodiments, the accuracy with which the constituent source measurements are approximated may be increased by implementing them as random sweeps having a conventional length.

Seismic source separation

A method and apparatus for generating a seismic source signal are provided for generating energy in the form of a plurality of time sequence vibratory signals, the vibratory signals being partitioned as a function of time and/or frequency, wherein each of the plurality of signals comprises a distinguishing signature. The partitioned vibratory signals are emitted into a terrain of interest as seismic source signals for conducting a seismic survey.

Acquiring seismic vibrator signals having distinguishing signatures

A seismic system has a plurality of seismic sources. Each of the seismic sources includes a reaction mass movable with respect to a geological structure and includes an actuator moving the reaction mass. The movement of the reaction mass emits a source signal as seismic energy into the geological structure. In the system, each of the source signals is generated from a base vibratory signal segmented into a plurality of segments, where the base vibratory signal sweeps from an initial frequency to a final frequency. Each of the segments has a partition of sweep frequencies different from the other segments. Each of the source signals has a distinguishing arrangement of the segments different from the other source signals.

Apparatus for generating seismic signals having distinguishing signatures

Generating seismic vibrator signals having distinguishing signatures

Processing seismic vibrator signals having distinguishing signatures

Generating seismic vibrator signals

A method of seismic surveying using one or more vibrational seismic energy sources activated by sweep signals. The highest order harmonic that has sufficient strength to cause significant harmonic distortion of a sweep segment is determined. A number of sweep segments in excess of the number of sources is selected. Initial phase angles are selected for each sweep segment of each seismic energy source so that substantially all harmonics up to and including the highest order harmonic are suppressed. Using cascaded sweeps, seismic data are acquired and processed to substantially attenuate harmonics upto the selected order.

Method of using cascaded sweeps for source coding and harmonic cancellation

A process for analyzing, decomposing, synthesizing and extracting seismic signal components, such as the fundamental of a pilot sweep or its harmonics, from seismic data uses a set of basis functions. The basis functions may be any of the harmonics or other components derived from the pilot sweep. These basis functions are modulated with the data being analyzed. The resulting data output from the modulation are then low-pass filtered so that the instantaneous amplitude and differential phase of the particular signal component to be synthesized may be computed. Each targeted component is then synthesized and the result subtracted from the remaining data.

Method for vibrator sweep analysis and synthesis

In a method for inverting a seismic signal, an input seismic signal is represented as an input vector i(t) of length m&plus;n&minus;1, an output seismic signal is represented as an output vector o(t) of length m, and a finite impulse response filter is represented as a solution vector u(t) of length n, satisfying a convolutional equation i(t){circle around (x)}u(t)&equals;o(t). An m&times;, n Toeplitz matrix T(t,&tgr;) corresponding to i(t) is calculated, satisfying a matrix equation T(t,&tgr;)&middot;u(t)&equals;o(t). Both sides of the matrix equation are transformed to a transform domain, to generate a transformed equation. Both sides of the transformed equation are pruned, to generate a pruned equation. The pruned equation is then solved. In one embodiment of the invention, the transformed domain is the frequency domain.

Efficient inversion of near singular geophysical signals

A method for inverting a seismic signal, wherein an input seismic signal is represented as an input vector i(t) of length m+n-1, an output seismic signal is represented as an output vector o(t) of length m, and a finite impulse response filter is represented as a solution vector u(t) of length n, satisfying a convolutional equation i(t)Xu(t)=o(t). An m.times.n Toeplitz matrix T(t,.tau.) corresponding to i(t) is calculated, satisfying a matrix equation T(t,.tau.).multidot.u(t)=o(t). Both sides of the matrix equation are transformed to the frequency domain, to generate a transformed equation. Both sides of the transformed equation are spectrally pruned, to generate a pruned equation. The pruned equation is then solved.

A method of compressing digital signals for transmission and/or storage. The method includes lossy compressing the digital signal to generate a lossy compressed signal. The compressed signal is decompressed locally to generate a local lossy decompressed signal. An error signal is calculated as the difference between the original digital signal and the local lossy decompressed signal. The power in the original digital signal and in the error signal is determined. A minimum resolution for quantizing the error signal is determined from a ratio of the power of the original signal with respect to power of the error signal. The error signals is lossy compressed by quantizing to at least the minimum resolution. Both the compressed digital signal and the compressed error signal are transmitted and/or stored. The lossy compressed error signal and the lossy compressed signal are recovered from storage or transmission. The lossy compressed signal and the lossy compressed error signal are decompressed, and the decompressed lossy compressed original signal and the decompressed lossy compressed error signal are summed to generate the recovered original digital signal.

Method for compression of high resolution seismic data

A method of reducing effects of noise in seismic signals generated by a plurality of seismic sensors at spaced apart locations from a seismic source is disclosed. Each of the signals is represented by a signal trace in a record section. The method includes the steps of isolating noise in the signal traces, time aligning corresponding portions of the noise in the traces thereby generating time-aligned noise traces, stacking the time-aligned noise trace to generate a stacked noise trace, replicating the stacked noise trace at each corresponding trace position in the record section, restoring the replicated traces to the original trace time positions by reversing the step of time-aligning to generate noise signature traces, comparing the noise signature traces to corresponding signal traces to generate filters which substantially minimize a measure of the difference between the noise signature traces and the signal traces. The noise signature traces are then filtered and the resulting filtered noise signature traces are subtracted from the signal traces. In a preferred embodiment the steps of comparing, generating filters, filtering and subtracting comprise linear adaptive filtering. In a particular embodiment the step of isolating the noise comprises bandpass filtering the signal traces.

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Houston, TX, United States of America

Gary Arthur Sitton