4D Interferometric Traveltime Tomography Yuqing Chen King Abdullah University of Science and Technology 11/12/2015
Outlines 1.Theory part Numerical Test Problem (also opportunities) Further plan
Theory
Theory Pre Fluid Post Fluid With time elapse , The velocity of the layer changes…
Theory Pre Fluid Post Fluid With time elapse , The velocity of the layer changes…
Advantage Multiples are more sensitivity to velocity change. Eliminate source and receiver statics
Method Instead of Raytracing, using approximate WET (wave path eikonal traveltime inversion) method to implement this method. Source side traveltime table: Receiver side traveltime table:
Method Add them together: Subtract observe time:
Method Cigar Rabbit ear Snake
Method Raytracing AWET
Numerical Test
Numerical Result
Static Test Update first layer Add static in traveltime Residual curve Similarity
First Layer Change Test
Second Layer Change Test Absolute time= Global velocity anomalies Differential time= Local velocity anomalies
Second Layer Change Test
Both Layer Change
(Left) Trace 20 & Residual curve (up) Both Layer Change Layer 1 (Left) Trace 20 & Residual curve (up)
(Left) Trace 20 & Residual curve (up) Both Layer Change Layer 2 (Left) Trace 20 & Residual curve (up)
Problem (or opportunities)
Problem 1: Convergence Property Approximate of Hessian of Multiples Approximate of Hessian of Reflection The difference of between the above two Hessian
Problem 2 : Traveltime Prediction The way we predict reflection and multiples
Problem 2 : Traveltime Prediction
Problem 2 : Traveltime Prediction Refraction Refraction-Reflection
Problem 2 : Traveltime Prediction Refraction multiples Refraction multiples
Problem 2 : Traveltime Prediction Gradient of Multiples Refraction of Reflection
Problem 2 : Traveltime Prediction Initial model True model
Problem 2 : Traveltime Prediction Initial model Inversion result
Problem 2 : Traveltime Prediction (Left) Trace 20 & Residual curve (up)
Future Plan
Further plan Real Data Test: Resonant Multiples Refraction Multiples