Abstract - Simple object- or pixel-based facies models use facies proportions as the constraining
input parameter to be honored in the output model. The resultant interconnectivity
of the facies bodies is an unconstrained output property of the modelling, and
if the objects being modelled are geometrically representative in three dimensions,
commonly-available methods will produce well-connected facies when the model
net:gross ratio exceeds about 30%. Geological processes have more degrees of freedom,
and facies in high net:gross natural systems often have much lower connectivity
than can be achieved by object-based or common implementations of pixel-based forward
modelling. The compression method decouples facies proportion from facies
connectivity in the modelling process and allows systems to be generated in which
both are defined independently at input. The two-step method first generates a model
with the correct connectivity but incorrect facies proportions using a conventional
method, and then applies a geometrical transform to scale the model to the correct
facies proportions while retaining the connectivity of the original model. The method,
and underlying parameters, are described and illustrated using examples representative
of low and high connectivity geological systems.
Mathematical Geosciences 55, 625-644, doi: https://doi.org/10.1007/s11004-023-10048-y, 2023.