Using Variograms in Facies Modelling?
Dear static modelers,
Can anybody help me with understanding the use of variograms in my facies modelling workflow. I have stared myself blind on the data analysis tab in Petrel and do understand what the Nugget is and what variograms indicate (variation in relation to distance). I understand that the sill indicates the spatial distance at which there is no more relation between the particular property.
However, when I change the search distance or radius the nugget and the sill changes all the time. Even when I can see in the little map inlay that no extra well locations are included in the calculation (the radius only expands outside the area in which we have wells).
Why is this occurring? And more importantly... which values of the nugget and sill should I use in the subsequence krigging? I think I understand the principles, but I can't seem to get consistent variograms fro my data. How should I interpret/use this?
thanks!
Janine