Conditioning Geologic Models to Local Continuity Azimuth in Spectral Simulation

Autor: Craig S. Calvert, Lincoln Foreman, Thomas A. Jones, Glen W. Bishop, Tingting Yao
Rok vydání: 2007
Předmět:
Zdroj: Mathematical Geology. 39:349-354
ISSN: 1573-8868
0882-8121
Popis: Spectral simulation has gained wider application in building geologic models because of the advantage of better honoring the spatial continuity of petrophysical properties, such as reservoir porosity and shale volume. A detailed review of the theoretical background of spectral simulation and how to condition the model to well data can be found in Yao (1998). Distinct from sequential simulation methods, spectral simulation is a global algorithm in the sense that a global density spectrum is calculated once and the inverse Fourier transform is performed on the Fourier coefficient also only once to generate a simulation realization. The generated realization honors the spatial continuity structure globally over the whole field instead of only within a search neighborhood, as with sequential simulation algorithms. However, the disadvantage of global spectral simulation is that it traditionally cannot account for local information such as the local continuity trend and local continuity azimuth, which are often observed in reservoirs and hence are important to be incorporated in geologic models. A recent paper by Yao et al. (2006) discussed a new method for accounting for local continuity trend, i.e., by gradually varying variogram range, in spectral simulation. Equally important local information in geologic modeling is the local direction of maximum continuity (or azimuth) of a petrophysical property. The orientation of the property may vary from one location to another, for example, to follow the curvilinear structure of meandering channels. In this short note, a new method of conditioning the geologic model to have locally varying azimuth is proposed, using a grid representing azimuths of maximum continuity.
Databáze: OpenAIRE
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