Total oil-in-place estimates for the Bakken petroleum system range from 160 billion barrels (Bbbl) to over 900 Bbbl. Most estimates for primary recovery range from 3% to 12%, depending on reservoir characteristics. With such low primary recovery factors and such a large resource, small improvements in productivity could increase technically recoverable oil in the Bakken by billions of barrels. While the use of carbon dioxide (CO2) in conventional reservoirs is a widely applied and well understood practice, its use for EOR in tight oil reservoirs is a relatively new concept. The EERC is conducting a multidisciplinary research program with the ultimate goal of providing industry with insight regarding the potential to use CO2 for EOR in the Bakken and Three Forks Formations. This research program is being conducted in two phases.
Phase I of the Bakken CO2 Enhanced Oil Recovery and Storage Program began in 2012 and will be completed in 2013. The objective of this first phase is to use reservoir characterization and laboratory analytical data (e.g., core analyses, well logs, oil analyses, etc.) coupled with state-of-the-art modeling to examine the viability of using CO2 for EOR in the Bakken. Key results include the following:
While results of the Phase I activities are encouraging, there is no clear-cut answer regarding the most effective approach for using CO2 to improve Bakken productivity. Some of the key questions that remain after the Phase I work include the following:
With these questions in mind, the EERC is planning a second phase of the Bakken CO2 Enhanced Oil Recovery and Storage Program. The objective of Phase II is to refine the techniques and approaches developed under Phase I and apply them to the design and implementation of an injection test in the field.