Steam Liquid coexistence

Hi, I’m a new Petrasim user and I would like to make some questions: I tried to build some geothermal model s and I have watched some tutorials and I’ve read some publications.

I can find lot of description concerning liquid fields, in which I start fixing the top of the model at atmospheric pressure to get a hydrostatic distribution of pressure, then I set one or more layers to a desired temperature and I run the simulation for a long time.

If I want to model a steam field I can’t use this model, so I looked for steam models and I found some publications about how to get the result of geological event (i.e  how to reproduce natural manifestation through virtual wells, how to reproduce a basal heat flux…). I found also another model in which a steam condition was imposed through vapor pressure and a fixed steam saturation. I’ve tried to follow this model but the second layer from the top reach a pressure value below atmospheric conditions. I can reach a steam reservoir just trough heat flux and high rock permeability (I suppose it’s normal and due to heat exchange mechanism).

It is correct to reproduce a given (and known) temperature-pressure distribution by fixing some elements and ignoring phenomena that could have led to this distribution?

How can I do to build a model in which a steam zone and a liquid zone coexist? For example what should I do if I know that at -1500 m below sea level some cells must be in steam conditions and the remaining must be in liquid phase? Do you have any suggestions or can you suggest me some publications or tutorial to read?