The following is an estimated oil production rate as function of time for a reservoir Production rate Bbl/day 100000 Mineral oil royalty Oil price Local Tax Operating cost Overhead Capital investment Bonus & Leasehold Year 3 4 5 8 90000 80000 60000 40000 30000 2000 1000 Calculate the yearly after tax net cash flow given: = 20% = $ 20/bbl = 15% of the net interest revenue = $ 5/bbl = $5 * 106 per year plus 20% on investment = $50 * 106 = $ 10 * 106 70% of the capital investment depreciated by sum of the year's digits method. 30% of the capital investment is expensed. The units of production method deplete the bonus & leasehold costs. The income tax rate is 40 %.