Vibro seismic source separation and acquisition

Patent metadata

Field	Value
Publication number	US-2016154131-A1
Application number	US-201414897002-A
Country	US
Kind code	A1
Filing date	Jun 26, 2014
Priority date	Jun 28, 2013
Publication date	Jun 2, 2016
Grant date	—

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.

First claim

1 . A method for separating seismic data, said method comprising:
acquiring seismic data associated with the firing of two or more sources in a time overlapping manner using sweep sequences that have low-level cross-correlations; recording a source signature for each of the two or more sources; and extracting a wave field associated with each of the two or more sources using the seismic data and the source signatures.

2 . The method of claim 1 , wherein one of the at least two sources generates seismic waves using a first sweep sequence and another of the at least two sources generates seismic waves using a second sweep sequence which is different than the first sweep sequence.

3 . The method of claim 2 , wherein the first sweep sequence and the second sweep sequence have a low-level cross-correlation value such that a ratio between a maximum of an auto-correlation of one of the first sweep sequence and the second sweep sequence and a mean level of cross-correlation between the first sweep sequence and the second sweep sequence is less than a predetermined threshold value.

4 . The method of claim 1 , wherein the sweep sequences with low-level cross correlations are one of: slip sweep sequences, sine waves having synchronized phase rotations with or without listening time, sine waves having unsynchronized phase rotations and random sequences.

5 . The method of claim 1 , wherein the source signatures are one of: near field measurements of outputs of each of the two or more sources, measurements of the two or more sources' actuator motion or pressure, or time-stamped sweep sequences.

6 . The method of claim 5 , wherein the source signatures are generated using a weighted sum of outputs of accelerometers located on a vibrator plate and a vibrator mass of each of the at least two sources.

7 . The method of claim 1 , wherein the step of extracting further comprises:
solving a multi-source convolution model from a continuous recording of seismic data.

8 . The method of claim 7 , wherein the step of extracting further comprises:
performing a time domain deconvolution process using the acquired seismic data and the source signatures.

9 . The method of claim 7 , wherein the step of extracting further comprises:
applying a conjugate-gradient algorithm to the seismic data.

10 . The method of claim 9 , wherein the conjugate gradient algorithm is performed in two or more iterations.

11 . A system for processing seismic data, said system comprising:
at least one processor which is configured to receive recorded seismic data associated with the firing of two or more sources in a time overlapping manner using sweep sequences that have low-level cross-correlations and a source signature for each of the two or more sources; and wherein the at least one processor is further configured to extract a wave field associated with each of the two or more sources using the seismic data and the source signatures.

12 . The system of claim 11 , wherein one of the at least two sources generates seismic waves using a first sweep sequence and another of the at least two sources generates seismic waves using a second sweep sequence which is different than the first sweep sequence.

13 . The system of claim 12 , wherein the first sweep sequence and the second sweep sequence have a low-level cross-correlation value such that a ratio between a maximum of an auto-correlation of one of the first sweep sequence and the second sweep sequence and a mean level of cross-correlation between the first sweep sequence and the second sweep sequence is less than a predetermined threshold value.

14 . The system of claim 11 , wherein the sweep sequences with low-level cross correlations are one of: slip sweep sequences, sine waves having synchronized phase rotations with or without listening time, sine waves having unsynchronized phase rotations and random sequences.

15 . The system of claim 11 , wherein the source signatures are one of: near field measurements of outputs of each of the two or more sources, measurements of the two or more sources' actuator motion or pressure, or the sweep sequences.

16 . The system of claim 15 , wherein the source signatures are generated using a weighted sum of outputs of accelerometers located on a vibrator plate and a vibrator mass of each of the at least two sources.

17 . The system of claim 11 , wherein the at least one processor is further configured to extract the wave fields by solving a multi-source convolution model from a continuous recording of seismic data.

18 . The system of claim 17 , wherein the at least one processor is configured to extract the wave fields by performing a time domain deconvolution process using the acquired seismic data and the source signatures.

19 . The system of claim 17 , wherein the at least one processor is extract the wave fields by applying a conjugate-gradient algorithm to the seismic data.

20 . A non-transitory computer-readable medium, having program instructions stored thereon which, when executed by a suitably programmed computing device, performs the steps of:
acquiring seismic data associated with the firing of two or more sources in a time overlapping manner using sweep sequences that have low-level cross-correlations; recording a source signature for each of the two or more sources; and extracting a wave field associated with each of the two or more sources using the seismic data and the source signatures.

Assignees

• Cgg Services Sa

Inventors

• Guillouet Matthieu
• Winter Olivier
• Bianchi Thomas

Classifications

• G01V1/375 Primary

  Correlating received seismic signals with the emitted source signal · CPC title

• G01V1/005

  with exploration systems emitting special signals, e.g. frequency swept signals, pulse sequences or slip sweep arrangements · CPC title

• G01V2210/50

  Corrections or adjustments related to wave propagation · CPC title