Researchers from University of Calgary developed a cyclic gas injection method with two pumping schedules for enhanced oil recovery
Restrictive economics and significant needs for special completion techniques are some of the major factors that restrict extraction of unconventional reservoirs. According to the 2013 U.S. Geological Survey (USGS) project reports, there are 7.4 billion barrels of unrecovered oil that can be produced from the Bakken and Three Forks formations. Now, a team of researchers from University of Calgary designed a CO2- enhanced oil recovery (EOR) scheme based on the fixed and growing-cycle sizes of gas injection and oil production.
The team also suggested four major scenarios: natural depletion, CO2 injection, ethane injection, and natural gas injection. The team focused on use of various cyclic gas injection situations with various fracture spacing to assess the efficiency of different designs of cyclic gas injection (CGI) for EOR in the Bakken formation. The team also conducted a sensitivity analysis to assess the effects of variations in fracking costs, oil price, and gas price on the ultimate cash flow.
The team found that fracking cost and gas price have least impact on project’s economy. The same was not true for decrease in oil price that demonstrated a vast impact. Moreover, oil price was the most significant factor among the variables in the project’s net present value (NPV) and internal rate of return (IRR). Cumulative NPV decreased when oil prices declined. This in turn suggested that decrease in oil price may lead to negative NPV and IRR when rest of the costs are constant. This leads to an uneconomic project. Gas prices had least impact on the economic responses and fracking cost demonstrated fewer impact on the profit compared with oil price. The research was published in the journal MDPI Energies on April 9, 2019.