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US 9,804,283 B2Granted
Vibro seismic source separation and acquisition
AssigneeCgg Services SAS
InventorsMatthieu Guillouet, Olivier Winter, Thomas Bianchi
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Abstract
Methods and systems for separating seismic data acquired using a plurality of substantially simultaneously fired sources are described. The sources use sweep sequences having low cross correlation levels to generate seismic waves, and their source signatures are determined. Using the source signatures, the wave fields associated with each of the sources are extracted from the seismic data by, for example, performing a time domain deconvolution.
Claims20
A method for separating seismic data, said method comprising:
- firing two or more sources in a time overlapping manner using sweep sequences that have low-level cross-correlations, wherein one of the at least two or more sources generates seismic waves using a first sweep sequence and another of the at least two or more sources generates seismic waves using a second sweep sequence, and wherein the low-level cross-correlation is defined as a ratio between (i) a maximum of an auto-correlation of one of the first sweep sequence and the second sweep sequence, and (ii) a mean level of cross-correlation between the first sweep sequence and the second sweep sequence,
- acquiring seismic data R associated with the firing of the two or more sources;
- recording a source signature Sk for each of the two or more sources;
- and
- extracting, by applying a convolution model, a wave field Ek associated with each of the two or more sources using the seismic data R and the source signatures Sk,
- wherein the convolution model considers that the seismic data R is a sum of convolutions of corresponding source signatures Sk and wave fields Ek,
- a matrix S associated with the source signatures Sk is a convolution operator,
- the wave fields Ek are obtained by using the seismic data R and a matrix STS, which is a product of (i) a transpose ST of the matrix S and (ii) the matrix S,
- matrix STS has non-diagonal terms that are cross-correlations of the source signatures Sk, and
- matrix STS has diagonal terms that are autocorrelations of the source signatures Sk.
7 more elements
A system for processing seismic data, said system comprising:
- at least one processor which is configured to receive (1) recorded seismic data R associated with the firing of two or more sources in a time overlapping manner using sweep sequences that have low-level cross-correlations and (2) a source signature Sk for each of the two or more sources, wherein one of the at least two or more sources generates seismic waves using a first sweep sequence and another of the at least two or more sources generates seismic waves using a second sweep sequence, and wherein the low-level cross-correlation is defined as a ratio between (i) a maximum of an auto-correlation of one of the first sweep sequence and the second sweep sequence, and (ii) a mean level of cross-correlation between the first sweep sequence and the second sweep sequence;
- and
- wherein the at least one processor is further configured to extract, by applying a convolution model, a wave field Ek associated with each of the two or more sources using the seismic data R and the source signatures Sk,
- wherein the convolution model considers that the seismic data R is a sum of convolutions of corresponding source signatures Sk and wave fields Ek,
- a matrix S associated with the source signatures Sk is a convolution operator,
- the wave fields Ek are obtained by using the seismic data R and a matrix STS, which is a product of (i) a transpose ST of the matrix S and (ii) the matrix S,
- matrix STS has non-diagonal terms that are cross-correlations of the source signatures Sk, and
- matrix STS has diagonal terms that are autocorrelations of the source signatures Sk.
5 more elements
A non-transitory computer-readable medium, having program instructions stored thereon which, when executed by a suitably programmed computing device, performs the steps of:
- firing two or more sources in a time overlapping manner using sweep sequences that have low-level cross-correlations, wherein one of the at least two or more sources generates seismic waves using a first sweep sequence and another of the at least two or more sources generates seismic waves using a second sweep sequence, and wherein the low-level cross-correlation is defined as a ratio between (i) a maximum of an auto-correlation of one of the first sweep sequence and the second sweep sequence, and (ii) a mean level of cross-correlation between the first sweep sequence and the second sweep sequence,
- acquiring seismic data R associated with the firing of the two or more sources;
- recording a source signature Sk for each of the two or more sources;
- and
- extracting, by applying a convolution model, a wave field Ek associated with each of the two or more sources using the seismic data R and the source signatures Sk,
- wherein the convolution model considers that the seismic data R is a sum of convolutions of corresponding source signatures Sk and wave fields Ek,
- a matrix S associated with the source signatures Sk is a convolution operator,
- the wave fields Ek are obtained by using the seismic data R and a matrix STS, which is a product of (i) a transpose ST of the matrix S and (ii) the matrix S,
- matrix STS has non-diagonal terms that are cross-correlations of the source signatures Sk, and
- matrix STS has diagonal terms that are autocorrelations of the source signatures Sk.
7 more elements
Dependencies are inferred from the claim text.