Pembina Cardium CO2 EOR 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. The Pembina Cardium Pool is the largest conventional oilfield in Canada in terms of OOIP and total oil produced. The OOIP is 7.5 billion barrels and recovery through June 2003 is 1.213 billion barrels or 16% of OOIP. Approximately 70% of the reservoir has been waterflooded and the average waterflood recovery is about 23%. Studies show that an EOR scheme could recover 15-20% or more of the OOIP over those portions of the reservoir that can be miscible flooded.
To test the technical and economic feasibility of CO2 EOR in the Pembina Cardium A Pool (mature waterflood), the applicant wishes to initiate a CO2 EOR pilot in a two, back-to-back inverted 5 spots on 20 acre spacing in the pool. A closer spacing of 20 acre for the pilot, as opposed to the current 40 acre for the A pool, was chosen by the applicant to get pilot information in a reasonable time period. The applicant is planning to use the existing 6 wells and drill 2 new injectors central to the 2 new patterns (with planned major workovers, 3 well reactivation and conversion of 2 existing water injectors back to producers). This pilot was chosen because it provided clean, well sorted Cardium sand with minimum heterogeneity and a thin and likely non- effective conglomerate zone (conglomerates can act as thief zone and thus preventing the CO2 from contacting the majority of oil, which is contained in the sand). The selection was also influenced by the fact that the area has been infill drilled to 40 acre spacing in 1972, thus the area has extensive production history for better simulation history matching, as well as closer spacing to provide early pilot results.
Injection is planned at 750 mcf/day/well of 98% pure CO2 (total 79 tonnes/day of CO2), and will last for 3-5 years. 75 tonnes/day of CO2 will be purchased by the applicant for an initial 2 year-period. Total CO2 injection over a 2-year period is planned at 1.1 bcf (58,000 tonnes CO2), equivalent to 34% HCPV of the pilot area. The applicant expects incremental CO2 EOR recovery of 20% OOIP of the pilot, bringing the ultimate recovery to 58% OOIP. Necessary field facilities will be built including a new pilot battery at 8-11-48-9W5 which will include inlet separators, a solution gas compressor, a dehydrator and CO2 injection facilities including associated equipment necessary for injection of breakthrough CO2. The production system will generally be stainless steel, fibreglass or lined or coated to prevent corrosion.
A pilot demonstrating that additional oil may be recovered from previously waterflooded areas of the Pembina Cardium A (which is representative of 30-40% of the total pool) would increase ultimate oil recovery in this major conventional oil pool in Alberta, in addition to potential replication for other non-Pembina Cardium pools. 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.