Zama acid gas EOR, CO2 sequestration, and monitoring project

Since October 2005, the Zama oil field in northwestern Alberta, Canada, has been the site of acid gas (approximately 80% CO2 and 20 H2S) injection for the simultaneous purpose of enhanced oil recovery (EOR), H2S disposal, and sequestration of CO2. Beginning in December 2006 and continuing through the present, injection has taken place at a depth of 1494 meters into one of over 800 pinnacle reef structures that have been identified in the Zama Subbasin. To date, over 36,000 metric tons of acid gas has been injected, resulting in incremental oil production over 25,000 barrels. Cost-effective monitoring at EOR sites that utilize H2S-rich acid gas as the sweep mechanism has been the overall goal of the project. The primary issues that have been addressed include (1) cap rock leakage, (2) long-term prediction of injectate, and (3) generation of data sets that will support the development and monetization of carbon credits. To address these issues, activities have been conducted at multiple scales of investigation in an effort to fully understand the ultimate implications of injection. Geological, geomechanical, geochemical, and engineering work has been used to fully describe the injection zone and adjacent strata in an effort to prove the long-term storage potential of this site. Through these activities, confidence in the ability of the Zama oil field to provide long-term containment of injected gas has been achieved. Results obtained from these activities can be applied not only to additional pinnacles in the Alberta Basin but to similar structures throughout the world.