Define layering for Norne

[olwijn]

First steps towards an implementation of layering in FlowNet:

1. Formulate criteria to define (number of) layers/zones - for now, base this on layers of the Norne Eclipse model
2. Determine if layers/zones are connected or not
3. Define a depth interval for each layer/zone at each (i,j) index
4. Implement a scheme to associate each defined well node with a layer/zone

Detailed steps:

• Enable user input for definition of nl layers in terms of k-index ranges (kstart, kend). See config_parser.py.
• In FlowData (from_flow.py), use EclGrid functions to compute layer thicknesses as a function of (I,J) indices and store in an array dimensioned (nx, nx, nl, 2) where the final dimension is used to specify kstart and kend for each of the nl layers.
• Currently only DATE, X,Y, Z and OPEN are available after applying the perforation strategy). See perforaton_strategy.py. Ensure that the k-index of each well node is kept as well.
• Using the k-index deduce the layer index and add as a property to each well node.