Preliminary Codes

1. 2-D prestack reverse-time migration by variable grid size and time step methods:(Yue Wang, 1999)

A staggered-grid finite-difference method is used to solve the two-way first-order elastic wave equation. Variable grid size and time step methods provides an algorithm which may be one-order magnitude faster than standard method for some models. Both pressure and particle-velocity data can be applied simultaneously and this combination can migrate both primary and water-bottom multiple/pegleg to correct reflection position.

2. 3-D prestack wavepath migration:(Hongchuan Sun, 1999)

After picking seismic events and computing incidence angles on the time-offset section, rays are traced into the medium from the geophone location. The true image point is along the raypath, and the migration aperture of 3-D wavepath migration (WM) is a small Fresnel volume centered about the image point. Numerical results show that 3-D WM can suppress migration artifacts and can define complex structure better than 3-D Kirchhoff migration (KM). The CPU comparison shows that 3-D WM can be more than an order-of-magnitude faster than 3-D KM, suggesting that WM is a potentially preferred method for 3-D iterative velocity analysis.

3. 3-D Migration Deconvolution:(Jianxing Hu, 1999)

3-D poststack migration deconvolution is to deconvolve migration Green's function from 3-D poststack migration image. Tests show that the migration deconvolution algorithm is suitable for both Kirchhoff migration and reverse time migration. It is able to noticebaly improve resolution, attenuate migration noise and correct the amplitude distortion in migration image.

4. 2-D Time Migration Deconvolution:(Jianxing Hu, 1999)

2-D poststack time migration deconvolution is to deconvolve migration Green's function from 2-D poststack time migration image. The result indicates that time migration deconvolution is able to attenuate migration artifacts, improved spatial resolution and image quality.

5. Migration Deconvolution with Regularization:(Jianxing Hu, 2001)

To improve the stability of the MD system, regularization of the MD system of equations is implemented. The numerical results show that migration deconvolution with regularization stabilizes the MD methods for all tested example.

6. Least Squares Migration Filtering (prepared by Jianhua Yu, May, 2001)

Least squares Migration Filtering (LSMF) is used for separating the horizontal and vertical component of multicomponent data. Time table and emergent angle information at receiver are required to be calculated using ray tracing code (see FORWARD MODELING CODE). A simple example is included.

7. The updated 3-D Traveltime Code with 3-D Salt Model Test (May, 2002)

This code is the update version of UTAM' 3-D traveltime calculation code. The code was tested on 3-D SEG/EAGE salt model.

8. 3-D Prestack Time Kirchhoff Migration (prepared by Jianhua Yu, May, 2002)

3-D prestack time migration is capable of migrating 3-D data cube for moderate complex structure. The code is tested on SEG/EAGE 3-D salt model (CN3) data with 6 processors on Icebox PC cluster. The parameter file and RMS velocity model are included. Data file is not uploaded on website because of the huge size. Here assumes that input data data is in SU format.

9. 3-D Prestack Depth Kirchhoff Migration (prepared by Jianhua Yu, June, 2002)

3-D prestack depth migration is capable of migrating 3-D data cube for complex structure. The code is tested on 3-D synthetic data from a simple model and part of data associated with3-D SEG/EAGE salt model (CN3) data with 6 processors on ICEBOX PC cluster. A example for a small size data set is included.

10. 2-D and 3-D Prestack Depth Wave-Equation Migration (prepared by Jianhua Yu, Aug. 2004)

Prestack wave-equation migration includes SSF and FFD algorithms that are tested on 2-D and 3-D synthetic data from a SEG/EAGE salt model. The parallel version of the codes running on ICEBOX PC cluster will be presented.

11. Migration of VSP First-order Ghost with Seminatural Green's Functions

Kirchhoff migration codes for imaging VSP first-order ghost using seminatural Green's functions. Codes passed tests under RedHat Linux system with Linux kernel 2.6.9-34.EL.

12. Acoustic Modeling Codes

Finite-difference acoustic forward modeling codes. None modification is made to the legendary ("PP4") code, except only one input file ("indat") is modified. Codes presented here passed tests under RedHat Linux system with Linux kernel 2.6.9-34.EL on a 32-bit AMD Athlon machine.

13. Multiple Filtering in Multiple Imaging and Primary Imaging

To filter different-order multiples.