Travel-time Tomography For High Contrast Media based on Sparse Data

Yenting Lin

Signal and Image Processing InstituteDepartment of Electrical Engineering

University of Southern California

February 3, 2013

Computed travel-time tomography is a powerful tool to produce tomographic image

Measure the signal response on the boundary Slices of specific area of the object, Non-destructive detection Widely used in geophysical and medical imaging

Computed Travel-time Tomography

ProblemsNot enough data - samples may be expensive

Travel-time tomography in geophysical application: Very expensive to setup sensors, drilling costs much time and money

Under-determined nonlinear inverse problem

High contrast structure Some natural structure have high contrast property Only need to separate the target structure and the

background Typical grid-based model and iterative reconstruction won’t

work well in this case

Our workReconstruct high contrast structure based on sparse travel-time data

Object based model – reduce the dimensionality The solution is not unique - estimate the probability

distribution of different models by randomized sampling techniques

Object based modelGrid based model

Water-flood tomography Apply our algorithm in petroleum application

Water is injected to support the pressure in the reservoir Use well injection and production data to estimate the

equivalent travel-time between well pairs Estimate the high permeability areas in an oil field

Probability map of high permGround truth in Simulator