Innovative Wave-Equation Migration

FEW 0000/AA06-02

Program
This project was funded through DOE's Natural Gas and Oil Technology Partnership (NGOTP) program. The program establishes alliances that combine the resources and experience of the Nation's petroleum industry with the capabilities of the National Laboratories to expedite research, development, and demonstration of advanced technologies for improved natural gas and oil recovery.

Project Goal
The goal of the project was to dramatically improve the capability of seismic migration for imaging complex structures that cannot be imaged by conventional seismic migration techniques.

Performer
Los Alamos National Laboratory
Los Alamos, NM

Project Results
Several wave-equation-based seismic migration methods have been developed and implemented for 2-D and 3-D depth imaging. Migration results of synthetic and real data sets of the new methods demonstrate that they can produce vastly improved images of complex structures compared with conventional migration methods.

Benefits
Ray theory-based Kirchhoff migration continues to be a major industry tool for imaging the Earth's subsurface structures for oil and gas exploration. This research provides industry with greatly improved migration algorithms based on wave theory. The new algorithms can produce more accurate images of complex regions than Kirchhoff migration can and can image complex structures that cannot be imaged by Kirchhoff migration. In addition, this research provides a novel approach for extracting physical information of materials during amplitude-preserving wave-equation migration for reliable seismic reservoir characterization, which is vital for resource assessment. The research of this project could significantly increase the success rate of oil and gas exploration in geologically complex regions such as those in the U.S. Gulf of Mexico.

Background
The complex structures beneath salt bodies are difficult to image using conventional ray-based Kirchhoff migration. As exploration for natural resources takes place in complex regions such as those below salt structures in the Gulf of Mexico, the use of wave-equation migration has become more popular in the petroleum industry. As the development of wave-equation migration is rather new for oil and gas exploration, many issues need to be addressed to allow this new technology to reach its full potential. In general, more accurate imaging methods are less computationally efficient. One challenge is to increase migration accuracy without increasing computational costs. Another challenge is to obtain physical information of materials other than geometrical structures from migration images for reliable reservoir characterization. These were the two primary issues addressed in this project.

The companies participating in this project included ADS, Amerada-Hess, Applied Geophysical Service, Baker Atlas, BHP, ChevronTexaco,ConocoPhillips,ExxonMobil, Fairfield Industries, Globe Exploration Service, Kerr-McGee, GX Technology, Paradigm, PGS, Screen Imaging, Shell, TomoSeis, Unocal, and Veritas DGC.

Project Summary
Among the major project achievements, researchers developed:

• A split-step Pade migration method.
• A split-step Fourier Pade migration method.
• A globally optimized Fourier finite-difference migration method.
• A stationary-phase wave-equation migration.
• A 3-D wave-equation migration method in the offset domain.
• Two controlled-aperture wave-equation migration methods.
• A method for extracting physical information from migration images.

Kirchhoff migration image

Wave-equation migration method developed by this project

Publications
Huang, L. and Fehler, M.C., Globally optimized Fourier finite-difference migration in three dimensions, proceedings of the 5th SEGJ International Symposium, 2001, Imaging Technology, pp. 67-74.

Huang, L. and Fehler, M.C., Advanced wave-equation migration, proceedings of the 5th International Symposium on Recent Advances in Exploration Geophysics (RAEG2001), 2001, pp. 38-45.

Roberts, P., House, L., Huang, L., Wiley, R., and Sekharan, K.K., 3-D imaging of seismic data from a physical model of a salt structure, proceedings of 71st Annual International SEG Meeting, 2001, pp. 1119-1122.

Huang, L., and Fehler, M.C., Split-step Pade migration, proceedings of 71st Annual International SEG Meeting, 2001, pp. 1041-1044.

Huang, L., and Fehler, M.C., Split-step Fourier Pade migration method, proceedings of 72nd Annual International SEG Meeting, 2002, pp. 1144-1147.

Fehler, M.C., and Huang, L., Modern imaging using seismic reflection data, Ann. Rev. Earth Planet. Sci., 2002, V. 30, 259-284.

Huang, L., and Fehler, M.C., Normal-reflection image, proceedings of 73rd Annual International SEG Meeting, 2003, pp. 929-932.

Huang, L, Sun, H, Fehler, M.C., and Li, Z., Controlled-aperture wave-equation migration, proceedings of 73rd Annual International SEG Meeting, 2003, pp, 1087-1090.

Huang, L, Sun, H., Fehler, M.C., Stationary-phase wave-equation migration, proceedings of 74th Annual International SEG Meeting, 2004, pp. 993-996.

Sun, H., Huang, L, Fehler, M.C., Controlled-aperture wavepath wave-equation migration, proceedings of 74th Annual International SEG Meeting, 2004, pp. 941-944.

Cheng, C.H., Huang, L., Sun, H., and Fehler, M., 2004. Crosswell seismic imaging of complex structures, proceedings of SEG/CSEG 2004 Meeting.

Fehler, M., Wu, R., Huang, L., and Xie, X., Numerical investigation of migration imaging resolution: Roles of data-acquisition configuration and imaging propagators, proceedings of the 7th SEG International Symposium-Imaging Technology, 2004, pp. 204-208.

Huang, L., Fehler, M., Li, Z., and Schultz, P., 3-D common-shot depth imaging with an optimized Fourier finite-difference scheme, proceedings of 75th Annual International SEG Meeting, 2005, accepted.

Sun, H., Huang, L., and Fehler, M., Globally optimized Fourier finite-difference migration in the offset domain, proceedings of 75th Annual International SEG Meeting, 2005, accepted.

Project Start: April 12, 2001
Project End: April 11, 2005

Anticipated DOE Contribution: $495,000
Performer Contribution: $0

Contact Information
NETL - Purna Halder (purna.halder@netl.doe.gov or 918-699-2083)
LANL - Lianjie Huang (ljh@lanl.gov or 505-665-1108)