Page 71 - Enhanced Oil Recovery in Shale and Tight Reservoirs

58 Enhanced Oil Recovery in Shale and Tight Reservoirs

Figure 2.47 Average well oil rate and the cumulative production within the pilot lease
(Hoffman, 2018).
injection. The cumulative oil production in 6 years had been increased by
30%. Hoffman (2018) did a simple economic estimate. It was assumed
that the infrastructure/capital costs were $1 million per well that included
the installation costs, well workover, and other costs; the gas price was
$2.5/Mscf, and oil price was $50/bbl; the discount rate was 15%; the gas
used for the initial fill up was considered “purchased,” and 20% of the sub-
sequent gas injected was considered the gas cost because most of the injected
gas would be produced back; 10% of the amount of injected gas was needed
to operate the fired compressors. Under those assumptions, the pilot internal
rate of return was 17.7% and the payback was 2.3 years. This pilot project
appeared to be a little over breakeven.