Enable aquifer settings to vary per layer

[edubarrosTNO]

I was trying to set up an example using both the layer and aquifer functionalities when I realized that I do not know how the aquifer nodes are being added to a FlowNet with two or more layers. My guess is that aquifer nodes would be connected to nodes from both layers. So the first question is: how are they being connected? Also with respect to the aquifer: fraction entry: e.g. if fraction: 0.25, would we be adding aquifer nodes to 25% of the nodes of each layer, or would we be adding aquifer nodes to 25% of the total number of nodes without respecting the proportion of nodes of each layer?

It could be useful to give the user control on this by enabling aquifer settings to be provided for each layer, e.g. we might want to have aquifer nodes connected only to the nodes of the lower FlowNet layer. What do you think?

[olelod]

FlowNet attaches aquifer flow tubes to the fraction deepest start/end points of any flow tubes in the model, so it is currently not regarding layers at all - only depth. If you have dipping layers, I guess you will get aquifer connection in all layers. When the layers are more flat, the aquifer will only connect to the bottom layer. Correct me if I'm wrong @wouterjdb. Shouldn't that be quite realistic? If we want to do it - I guess that implementing aquifer connections in all layers is not very time consuming to implement.

[olwijn]

One issue I see with connecting to e.g. the 25% deepest nodes is that we will also be connecting to injectors. Does it make sense at all to connect to injectors? In Norne there are separate oil-water contacts for the 2 disconnected zones so you could also imagine separate aquifer connections for wells in the top zone (layers 1 to 3 of the full model) and wells in the lower zone (layers 5 to 22 of the full model). From looking at the full model there appears to be some (vertical) coning and one or two areas of lateral inflow from water-saturated regions.