RCT here's 2 re gas but go look at the valuation Cove (?1.25b - 2012) acheived for it's small 8.5% interest in a major offshore Gas find in Mozambique that was bought by PTT of Thailand last year and about 3 - 5 years from development. Approx 2.5 Tcf for ?1.25b or 80c per mcf.
Also look at the valuation of Ophir and its gas discoveries (?1.8b+ - 2013) deep water Africa (high capex).
If you think oil is only valued at $1/b (yes Russia is not unusual for this).
Een in 2009 under 30 mmbo P2 sold for ?530m circa $26/b Amer 29.9 mmbo P2 and a ?600m valuation today circa $30/b.
Chinas gas market is roaring and Far East Resources 2010 signed a 20 year deal for CBM gas at $6.55/mcf (Rates are expected to rise to $8-$9 mcf average $50/b so i'd expect a value of $1-$2 per mcf (in line with Argonauts $500m - $1b valuation for 0.5 Tcf reserve).
Emerald Shareholders will be entitled to receive 750 pence in cash for each Emerald Share, valuing the entire issued and to be issued ordinary share capital of Emerald at approximately ?532.1 million.