CTP Profit project for next 15 years based on IER table, page-9

You also need to add in capital costs including sustaining capex and also admin/overheads. And either extra dilution to pay for the capex or extra debt. You also do need to consider tax, once the accumulated tax losses are paid off it's going to hit pretty hard.

Also IIRC that revenue figure actually includes the oil production forecast, not just gas. Just something to keep in mind.

All in all the "average profit $3.75/GJ" is going to be far, far too high. What you have actually calculated there is operating margin, not net profit. You can't base a P/E share price forecast on operating margin.