Here is my best guess of Eco's three best blocks:
3b/4b:
Total Potential barrels = 3,000,000,000
Stake : 20%, likely to be farmed down to 10% for two carried wells or $17,000,000 per most recent transaction
Succesful find valuation: 300,000,000 X $1 per barrel
Orinduik:
Total Potential barrels = 2,000,000,000 (Cretaceous)
Stake : 15%
Succesful find valuation: 2 billlion X .15 = 300 Mil X $3 per barrel = $900,000,000
Guy:
Total Potential barrels = 5,000,000,000
Stake : 80%, likely to be farmed down to 20% for unknown amount
Succesful find valuation: 5 billion X .20 = 1 Billion X $1 per barrel
That's my best back of the envelope calculation.