The water/gas press. are calculated only if woc/goc is within the reservoar 

The water/gas pressure used for the calculation of the phase saturation and the rs values is set to -inf when woc/goc is above or below the reservoir. With this fix in the initialization OPM reproduces Eclipse results for SPE9. 

 
(A note about your comment: it does not show up here, I think it is because it is associated with the commit, and not the diff, if you comment in the "Files changed" tab that is the best I think.)

I think you should have used local_index here (and below for the gas case), see the assign() function that is called from for example oil() and gas() to compare. Essentially, I think the vector we write to here has size equal to the number of cells in the block, not to all cells. Also, since all you are doing in the loop is assign a single value, a better choice would be:
```
press[wix].assign(cells.size(), po_woc);
```