Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Earth science
Patent
1999-06-18
2000-09-26
McElheny, Jr., Donald E.
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Earth science
G01V 128
Patent
active
061253308
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to methods of determining the seismic response caused by alterations of a model in simulations of wave propagation. More specifically, it relates to determining the seismic response caused by model alterations in finite-difference (FD) simulations.
BACKGROUND OF THE INVENTION
A wide variety of seismic modeling, processing and inversion algorithms require the recalculation of the seismic response after incremental local alterations to an initial seismic finite-difference model. For example, pre-stack finite-difference migration of seismic data provides a highly accurate means of producing images of the Earth's interior. The migration algorithm consists of recalculating the finite-difference response of small local changes to the seismic model. However, full finite-difference migration is rarely performed because of computational limitations restricting migration algorithms to the use of less accurate asymptotic techniques. Another example relates to finite-difference inversion, where recalculating the finite-difference response is the core (forward modeling step) of the algorithms.
Yet another example which is considered as being an important area of the present invention refers to so-called time-lapse seismics (or 4-D seismics). In this application it is of interest to investigate the effects that small (local) changes to the model have on the seismic response, e.g., varying water-oil-contact levels in a producing reservoir.
Also, in forward modeling, it may be of interest to re-compute the response of an altered seismic model. Forward modeling may serve as a means of learning what effects certain features of a seismic model have on the full response. Also, as the knowledge of the model evolves, or as it becomes more refined, a simulated response may need to be updated.
Another area of interest regarding the present invention lies in Amplitude Variation with Offset (AVO) calculations, where the effects of, for instance, changes of the degree of anisotropy of a cap-rock may be the target of investigation.
Furthermore, FD modeling has been used in connection with borehole measurements, simulations of tool behavior and characteristics in their operational environment. Typically, it is of interest to investigate the effects that small changes to the tool design or model parameters have on the propagation of waves in the vicinity of the tool.
The common feature of these problems is that changes to the model are often restricted to a small sub-volume, but finite-difference simulations are required for the full model with several alterations. A method that would allow full finite-difference simulations for the complete model to be corrected for these changes while only requiring calculations in the sub-volume and its neighborhood could significantly reduce the computational cost both in terms of the number of calculations and memory for storage of material parameters and variable fields.
Finite-difference methods provide an accurate way of computing seismograms from complex seismic models. However, as mentioned above, the finite-difference simulations tend to become prohibitively expensive to run on even state-of-the-art computing equipment. Therefore, different approaches have been taken to make highly accurate numerical modeling methods such as finite-difference schemes more efficient. Two major directions of effort to achieve significant computational savings can be found in the literature: (1) hybrid techniques; and (2) grid-refinement techniques.
By combining methods appropriate for different wave propagation regimes, it is possible to increase computational efficiency as well as the simulation accuracy considerably. For details of such an approach, reference is made to Wu, R. S. and R. Aki, 1988, Introduction: Seismic wave scattering in three-dimensionally heterogeneous Earth, in: Scattering and Attenuation of Seismic Waves, edited by K. Aki and R. S. Wu, pp. 1-6. Birkhauser Verlag, Basel, Switzerland. Several such hybrid techniques have been developed for seismic applicatio
REFERENCES:
patent: 5062086 (1991-10-01), Harlan et al.
patent: 5067113 (1991-11-01), Hanson et al.
patent: 5394325 (1995-02-01), Schneider, Jr.
patent: 5481501 (1996-01-01), Blakeslee et al.
patent: 5648939 (1997-07-01), Folstad et al.
Fischer, R., Lees, J. M. Shortest path ray tracing with sparse graphs Geophysics, Jul. 1993, USA, vol. 58, No. 7, pp. 987-996 XP002086253, ISSN 0016-8033.
Alterman, Z., Karal, F. C., JR. Propagation of elastic waves in layered media by finite difference methods Bulletin of the Seismological Society of America, 1968, vol. 58:1, 367-398, pp. 4-35.
Bergmann, T., Robertsson, J. O. A., Holliger, K. Numerical properties of staggered finite-difference solutions of Maxwell's equations for ground-penetrating radar modeling Geophysical Research Letters, Jan. 1996, vol. 23, No. 1, pp. 45-48.
Emmerich, H. 2-D wave propagation by a hybrid method Geophys. J. Int., 1989, vol. 99, pp. 307-319.
Emmerich, H. PSV-wave propagation in a medium with local heterogeneities: a hybrid formulation and its application Geophys. J. Int., 1992, vol. 109, pp. 54-64.
Fah, D., Suhadolc, P., Mueller St., Panza, G. F. A hybrid method for the estimation of ground motion in sedimentary basins: quantitative modeling for Mexico City Bulletin of the Seismological Society of America, Apr. 1994, vol. 84, No. 2, pp. 383-399.
Kelly, K. R., Ward, R. W., Treitel, S., Alford, R. M. Synthetic seismograms: A finite-difference approach Geophysics, Feb. 1976, vol. 41, No. 1, pp. 2-27.
Kosloff, R., Kosloff D. Absorbing boundaries for wave propagation problems Journal of Computational Physics, 1986, vol. 63, pp. 363-376.
Kummer, B., Behle, A., Dorau, F. Hybrid modeling of elastic-wave propagation in two-dimensional laterally inhomogeneous media Geophysics, Jun. 1987, vol. 52, No. 6, pp. 765-771.
Kurkjian, A. L., Coates, R. T., White, J. E., Schmidt, H. Finite-difference and frequency-wavenumber modeling of seismic monopole sources and receivers in fluid-filled boreholes Geophysics, Jul. 1994, vol. 59, No. 7, pp. 1053-1064.
Lecomte, I. Hybrid modeling with ray tracing and finite difference 66.sup.th Annual Meeting of Society of Exploration Geophysicists, Denver, Col., 1996, pp. 699-702.
Levander, A. R. Finite-difference forward modeling in seismology The Encyclopaedia of Solid Earth Geophysics, edited by D. E. James, 1989, pp. 410-431. Van Nostrand Reinhold, New York.
McLaughlin, K. L., Day, S. M. 3D elastic finite-difference seismic-wave simulations Computers in Physics, Nov./Dec. 1994, vol. 8, No. 6, pp. 656-663.
Robertsson, J. O. A., Blanch, J. O., Symes, W. W. Viscoelastic finite-difference modeling Geophysics, Sep. 1994, vol. 59, No. 9, pp. 1444-1456.
Robertsson, J. O. A., Levander, A., Holliger, K. Modeling of the acoustic reverberation special research program deep ocean seafloor scattering experiments using a hybrid wave propagation simulation technique Journal of Geophysical Research, Feb. 1996, vol. 101, No. B2. pp. 3085-3101.
Robertsson, J. O. A., Levander, A., Holliger, K. A hybrid wave propagation simulation technique for ocean acoustic problems Journal of Geophysical Research, May 1996, vol. 101, No. B5, pp. 11225-11241.
Robertsson, J. O. A., Holliger, K. Modeling of seismic wave propagation near the earth's surface Physics of the Earth and Planetary Interiors, 1997, vol. 104, pp. 193-211.
Shtivelman, V. A hybrid method for wave field computation Geophysical Prospecting, 1984, vol. 32, pp. 236-257.
Shtivelman, V. Two-dimensional acoustic modeling by a hybrid method Geophysics, Aug. 1985, vol. 50, No. 8, pp. 1273-1284.
Stead, R. J., Helmberger, D. V. Numerical-analytical interfacing in two dimensions with applications to modeling NTS seismograms Pure Appl. Geophys., 1988, vol. 128, Nos. 1/2, pp. 157-193.
Vidale, J. E., Helmberger, D. V. Seismic strong motion synthetics: Path effects in strong motion seismology Computational Techniques, 1987, Academic Press, San Diego, Cal., pp. 267-317.
Zahradnik, J., Moczo, P. Hybrid seismic modeling based on discrete-wave number
Chapman Christopher H.
Robertson John Olof Anders
Batzer William B.
McElheny Jr. Donald E.
Schlumberger Technology Corporation
Wang William L.
LandOfFree
Method of determining the response caused by model alterations i does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of determining the response caused by model alterations i, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of determining the response caused by model alterations i will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2108218