Swan Hills Unit CO2 Pilot

Enhanced oil recovery using Carbon Dioxide as miscible flooding injectant (CO2 EOR) can significantly improve oil recovery from certain mature large conventional oil fields in Alberta.  In the Swan Hills Unit No.1 (SHU1), the better quality areas of the pool have been previously waterflooded and miscibly flooded using hydrocarbon solvent (HCMF). The ultimate oil recovery factor (UOR) currently recognized by EUB for the miscible flood project in SHU1 is 48% of OOIP.

The applicant wishes to initiate a CO2 EOR pilot project in Pattern ‘S’ by injecting CO2 into the B6/B5 interval (uppermost interval of pay zone) in the pilot area (Pattern ‘S’ will be configured to inject and produce from only the B6/B5 zones). Pattern ‘S’ is located in the highest position structurally within the entire reef complex, and it contains one injector and 5 producers on 80 acre spacing. Solvent injection in Pattern ‘S’ commenced in December 1985 and was terminated in 1995 with approximately 140,870 e3 m3 (5 Bcf) of solvent injection, which equates to 31.6% of the pattern HCPV, with B6 receiving injected solvent equivalent to approximately 65% of its zonal HCPV. The pattern has been on terminal waterflood since May 1995. Pattern ‘S’ was selected for this pilot because it is a small pattern in a mature area of the field that has been flooded with hydrocarbon solvent, it is isolated from recent or on-going hydrocarbon solvent injection, the reservoir pressure is above the CO2 minimum miscibility pressure and the reservoir within the pattern is stratified with numerous continuous intervals. The applicant is planning to inject a 10% HCPV (zonal) of CO2 or 33,660 tonnes to verify the ability to safely inject and produce CO2 with minimal corrosion, scale or asphaltene problems, and to confirm reservoir model predictions for trapped solvent recovery, incremental oil recovery and CO2 sequestration.
The targeted zone B6/B5 is isolated from the remainder of the reef build up in this pattern by a shale barrier (this provides good control and monitoring of flood performance).

About 110 tonnes /day (2 MMCFD) of CO2 will be trucked to the pilot, with 10 injection cycles of CO2 and water at 1:1 ratio over a 19 month period. The required storage and pumping facilities will be located at the 2-16-67-10W5 well site, and the equipment will be connected to the Unit control center via SCADA so it can be monitored continuously.
 
A pilot demonstrating that additional oil may be recovered from previously “hydrocarbon solvent” flooded areas of the Swan Hills Beaverhill Lake would increase ultimate oil recovery in this second largest conventional oil pool in Alberta, as well as potential replication for other Beaverhill Lake pools in the Swan Hills region . The use of CO2 as the miscible agent would also result in the permanent sequestration of significant volumes of carbon dioxide.

The following reports are currently available for public access:

Quarterly reports are available upon request – please contact EIPA.