Hi...

Hi Oscar,

http://www.barnettshalenews.com/documents/2009/2009%20Tarrant%20County%20Barnett%20Shale%20Revenue%20Estimate%20for%20Neighborhoods.pdf

This is pretty detailed for Barnett Shale wells in Tarrant County. You could just go to the last page which really spells out the 30yr production using relevant decline curve and royalties to end up with total cash for that 30 years (in this example circa $14M net)


I just used an online NPV on investopedia that only looked at 10 years

Discount Rate: 10%
Life of Project: 10years
Initial Cost: -$2.6M

Net cash each year for first 10 years at $6Mcf
Cash flow 1: $2.268M
Cash flow 2: $1.282M
Cash flow 3: $0.989M
Cash flow 4: $0.849M
Cash flow 5: $0.772M
Cash flow 6: $0.711M
Cash flow 7: $0.654M
Cash flow 8: $0.601M
Cash flow 9: $0.553M
Cash flow 10:$0.509M

Net Present Value: $3,771,687.16
PV of Expected Cash flows: $6,371,687.16


Interpretation:

With a discount rate of 10.00% and a span of 10 years, your projected cash flows are worth $6,371,687.16 today, which is greater than the initial $2,600,000.00 paid. The resulting positive NPV of the above project is $3,771,687.16, which indicates that pursuing the above project may be optimal.

Read more: http://www.investopedia.com/calculator/NetPresentValue.aspx#ixzz1Xzv2hHgY