Abstract - This study investigates whether pixel-based geostatistical modelling methods
can be used to generate high net:gross ratio models with low connectivity of the net
facies, a common combination in many natural geological systems. Connectivity as a
function of net:gross is systematically measured in stationary, representative, horizontally
isotropic three-dimensional models generated using three different pixel-based
geostatistical methods: sequential indicator simulation, truncated Gaussian simulation
and multiple-point statistics modelling. All methods are found to have percolation
thresholds similar to, or substantially lower than, that of a random object-based model
in which the net facies becomes macroscopically connected at a critical net:gross ratio
of 0.27. A geometrical transformation previously defined for object-based models
known as the compression method has been adapted to deal also with pixel-based
models. Application of the method, calibrated using the newly established percolation
thresholds, allows construction of geologically realistic facies models using a range of
pixel-based methods. The resultant models contain quantifiable levels of connectivity
that are defined independently of the model net:gross ratio.
Mathematical Geosciences, 2021, doi: https://doi.org/10.1007/s11004-021-09931-3