Define two or more overlay facies by the same GRF within the same background facies

[ingunnr]

Allow two or more overlay facies to be defined by the same GRF. This implies that truncation rule for the GRF for overlay facies is truncated by defining more than one truncation interval for overlay facies. The purpose is to create overlay facies that are neigbours to other overlay facies like channels plus crevasse/levees. Today this must be modelled as facies using the background facies truncation rule settings or in a nested modelling workflow using regions.

Example:

The figure to the left illustrate the current implementation where only one overlay facies is defined per GRF within the same background facies. Here the two blue colors represent background facies. The orange color represent the overlay facies. Note that alpha 3, the GRF that define the overlay facies, will give overlay facies if the alpha3 value is within the orange interval and keep the background facies if outside that interval.The blue interval in alpha3 represents all background facies.
The figure to the right is an extension where two different overlay facies is defined by two different intervals of alpha3 value. This will result in two overlay facies that are neighbour to each other and could e.g. be useful if channel and crevasse is modelled, both as overlay facies overprinting some bachground facies.