Abstract

Lloydminster area that straddles Alberta and Saskatchewan border contains vast amounts of heavy oil deposits in thin unconsolidated formations. It is believed that the heavy oil resource volume is in the 50 to 70 billion bbl range which makes it a world class resource. This work briefly summarizes the reservoir properties of these formations and provides an overview of the primary CHOPS recovery mechanism which only recovers on average 8% of the original oil in place. Therefore, the target for Enhanced Oil Recovery (EOR) processes are substantial. For instance, if an additional 2% (25% of the primary) oil can be recovered, this means an additional 1 to 1.5 billion bbls of oil production which can sustain the oil industry for many years in this area providing jobs and contributing significantly to government royalties.

A critical literature review of Cyclic Solvent Injection (CSI) as a post-CHOPS EOR technology is conducted. The key aspects of laboratory and theoretical studies of methane and propane mixtures, CO2 and propane mixtures and pure CO2 injection are summarized. A number of field pilots have been conducted using these solvents in post-CHOPS reservoirs in Lloydminster.

Implementation of field pilots is presented and results are discussed using publicly available data. It is shown that while CSI technology is technically successful, economic feasibility is more elusive. However, it appears that CO2 injection is more likely to be economically successful. Furthermore, the economic attractiveness of Cyclic CO2 Injection increases in an environment where greenhouse gas emissions are taxed and credits for disposal are available.

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