Estimated at 2.5 trillion barrels, Canada has the world's largest share of ultra-heavy oil and bitumen resources. While shallow heavy oil reserves are extracted from pit mines, deeper reserves can only be extracted through wells. Production of these reserves requires methods such as steam-assisted gravity drainage (SAGD) and cyclic steam simulation (CSS) (Butler, 1991). Optimal well placement defines the propagation of steam within the reservoir and the resulting flow of crude.
SAGD recovery methods require tremendous amounts of steam in order to get the crude to flow. Costs to generate and inject steam in a SAGD pad are significant. Finding ways to use steam more effectively in these operations should result in increased production efficiency and improved financial return on these projects. By strategically placing steam injectors and by controlling the amount of steam injected it may be possible for these results to be achieved.
A study was conducted to examine several completion strategies and to test, with the use of a simulation model, what the expected production, and steam requirements for these strategies would be. The simulation model examined multiple well pairs to see these results in a full-field environment. To assess the financial impact of these strategies, a fiscal model was developed that evaluated SAGD project costs and then examined the incremental cost and value of each of the completion strategies. Results show that although using steam effectively in these strategies may not yield the highest recovery, it does improve the expected value of these projects.
This paper describes the process, operational control, and financial analysis used to design and validate the SAGD model. The study focuses on a completion strategy that demonstrates a strong potential to reduce SOR and ultimately operational cost. Incremental financial analysis is included to examine the impact of choosing any such strategy.