Transitive Geostatistics for Stepwise Modeling Across Boundaries between Rock Regions |
| |
Authors: | J A Vargas-Guzmán |
| |
Institution: | (1) P.O. Box 13734, Dhahran, 31311, Saudi Arabia |
| |
Abstract: | A single intrinsic stationary random field may not account for transitional heterogeneity and abrupt dissimilarity of geological
properties across boundaries between rock type regions. This paper proposes the stepwise construction of transitive covariance
models for modeling continuous properties correlated across boundaries of multiple disjoint physical domains such as rock
type bodies. Modeling in geology is usually simplified by splitting the geological space into rock type geo-domains (e.g.,
strata, sedimentary facies, soil series, diagenetic regions and alteration zones). Due to the limitations of simultaneous
solutions, a simplification is to model each domain independently at the cost of losing the conditioning of properties across
domains. This paper proposes to organize the modeling process in a triangular array which follows events in the geological
time domain; for example, the younger formations are at the top of the pyramid and the older formation at the base. The estimation
may go from top to base by assuming that younger events have perturbed older formations. Geology shows the scars of events
that cumulate in rock formations before they are finally eroded. In some cases, older formations may be parent material for
younger formations. The continuous property within each geo-domain has a conditional covariance in the main diagonal of the
array which may belong to a specific event in the geological time. This sequence leads to transitive estimation and simulations
in the physical space. If a simultaneous solution is sought (i.e., the future and past are correlated both ways), the complex
covariance functions can be constructed stepwise from conditional spectra. |
| |
Keywords: | Petrophysical properties Rock types Diagenesis Multivariate geostatistics Conditional spectra Spatio-temporal Piecewise non-stationarity Large field models |
本文献已被 SpringerLink 等数据库收录! |
|