This invention establishes a method and
system for three-dimensional
facies-controlled sand body modeling and
connectivity evaluation. The method is based on a dimensionality-reduction modeling architecture: a planar sedimentary
facies distribution map is generated through probability-guided sequential indicator
simulation; under the constraint of planar
facies zones, a one-dimensional vertical sequence of interbedded sand and mud
layers is independently generated point-by-point using probabilistic sampling; the planar facies map and the vertical sequence are stitched together in three-dimensional space; then, based on
graph theory undirected graph algorithms, the
connectivity of the three-dimensional sand body is identified using vertical depth interval overlap and non-interlayer
occlusion as dual criteria; finally,
connectivity uncertainty is quantified through Monte Carlo iteration. Compared with traditional full-3D grid sequential
Gaussian simulation, this method is applicable to clastic reservoirs with gradual
lateral variation and dominant vertical accretion (
lateral variation coefficient of planar facies zones less than 0.3). It eliminates the computationally expensive three-dimensional spatial interpolation and complex structural modeling, forming a simplified
engineering path of "trading computational power for uncertainty assessment," which can be used for reservoir connectivity evaluation and development scheme optimization.