Applying Compactness Constraints to Seismic Traveltime Tomography

Tomographic imaging problems are typically ill-posed and often require the use of regularization techniques to guarantee a stable solution. Minimization of a weighted norm of model length is one commonly used secondary constraint. Tikhonov methods exploit low-order differential operators to select f...

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Main Authors: Ajo-Franklin, Jonathan B., Minsley, Burke J., Daley, T. M.
Other Authors: Massachusetts Institute of Technology. Earth Resources Laboratory
Format: Technical Report
Published: Massachusetts Institute of Technology. Earth Resources Laboratory 2012
Online Access:http://hdl.handle.net/1721.1/67921
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author Ajo-Franklin, Jonathan B.
Minsley, Burke J.
Daley, T. M.
author2 Massachusetts Institute of Technology. Earth Resources Laboratory
author_facet Massachusetts Institute of Technology. Earth Resources Laboratory
Ajo-Franklin, Jonathan B.
Minsley, Burke J.
Daley, T. M.
author_sort Ajo-Franklin, Jonathan B.
collection MIT
description Tomographic imaging problems are typically ill-posed and often require the use of regularization techniques to guarantee a stable solution. Minimization of a weighted norm of model length is one commonly used secondary constraint. Tikhonov methods exploit low-order differential operators to select for solutions that are small, flat, or smooth in one or more dimensions. This class of regularizing functionals may not always be appropriate, particularly in cases where the anomaly being imaged is generated by a non-smooth spatial process. Timelapse imaging of flow-induced seismic velocity anomalies is one such case; flow features are often characterized by spatial compactness or connectivity. We develop a traveltime tomography algorithm which selects for compact solutions through application of model-space iteratively reweighted least squares. Our technique is an adaptation of minimum support regularization methods previously developed within the potential theory community. We emphasize the application of compactness constraints to timelapse datasets differenced in the data domain, a process which allows recovery of compact perturbations in model properties. We test our inversion algorithm on a simple synthetic dataset generated using a velocity model with several localized velocity anomalies. We then demonstrate the efficacy of the algorithm on a CO2 sequestration monitoring dataset acquired at the Frio pilot site. In both cases, the addition of compactness constraints improves image quality by reducing spatial smearing due to limited angular aperture in the acquisition geometry.
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spelling mit-1721.1/679212019-04-12T15:05:36Z Applying Compactness Constraints to Seismic Traveltime Tomography Ajo-Franklin, Jonathan B. Minsley, Burke J. Daley, T. M. Massachusetts Institute of Technology. Earth Resources Laboratory Ajo-Franklin, Jonathan B. Minsley, Burke J. Tomographic imaging problems are typically ill-posed and often require the use of regularization techniques to guarantee a stable solution. Minimization of a weighted norm of model length is one commonly used secondary constraint. Tikhonov methods exploit low-order differential operators to select for solutions that are small, flat, or smooth in one or more dimensions. This class of regularizing functionals may not always be appropriate, particularly in cases where the anomaly being imaged is generated by a non-smooth spatial process. Timelapse imaging of flow-induced seismic velocity anomalies is one such case; flow features are often characterized by spatial compactness or connectivity. We develop a traveltime tomography algorithm which selects for compact solutions through application of model-space iteratively reweighted least squares. Our technique is an adaptation of minimum support regularization methods previously developed within the potential theory community. We emphasize the application of compactness constraints to timelapse datasets differenced in the data domain, a process which allows recovery of compact perturbations in model properties. We test our inversion algorithm on a simple synthetic dataset generated using a velocity model with several localized velocity anomalies. We then demonstrate the efficacy of the algorithm on a CO2 sequestration monitoring dataset acquired at the Frio pilot site. In both cases, the addition of compactness constraints improves image quality by reducing spatial smearing due to limited angular aperture in the acquisition geometry. Toksoz, M. Nafi Massachusetts Institute of Technology. Earth Resources Laboratory 2012-01-05T19:58:28Z 2012-01-05T19:58:28Z 2006 Technical Report http://hdl.handle.net/1721.1/67921 Earth Resources Laboratory Industry Consortia Annual Report;2006-09 application/pdf Massachusetts Institute of Technology. Earth Resources Laboratory
spellingShingle Ajo-Franklin, Jonathan B.
Minsley, Burke J.
Daley, T. M.
Applying Compactness Constraints to Seismic Traveltime Tomography
title Applying Compactness Constraints to Seismic Traveltime Tomography
title_full Applying Compactness Constraints to Seismic Traveltime Tomography
title_fullStr Applying Compactness Constraints to Seismic Traveltime Tomography
title_full_unstemmed Applying Compactness Constraints to Seismic Traveltime Tomography
title_short Applying Compactness Constraints to Seismic Traveltime Tomography
title_sort applying compactness constraints to seismic traveltime tomography
url http://hdl.handle.net/1721.1/67921
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