CO2 EOR and storage in Jilin oilfield China: Monitoring program and preliminary results

• The first large CCS demonstration project in combination with EOR in China.
• A comprehensive and effective monitoring program was designed and implemented.
• Tracking CO2 migration effectively using gas tracers and ESP measurement.
• 200,000 tons of CO2 was injected and the primary storage efficiency is nearly 80%.

Jilin oilfield is conducting the first large scale demonstration project on CO2 EOR and storage in the northeast China. CO2 with high purity is produced from a nearby natural gas reservoir and injected into the tight oil reservoir of H-59 block. Up to early in 2012, more than 20×104 tons of CO2 has been injected into the reservoir through a miscible flooding scheme. In order to track the migration of CO2 in the reservoir and ensure a long-term storage safety, a monitoring program has been deployed in the field. The used monitoring techniques include wellbore integrity detecting, produced fluid sampling, CO2 gas tracer, electric spontaneous potential measurement, micro-seismic and cross-well seismic. An environmental monitoring program is also implemented for verifying CO2 leakage. Preliminary results indicate that it is effective to detect the movement of CO2 in the oil reservoir by jointly applying various monitoring techniques based on wellbores. After more than four years of operation since 2008, nearly 80% of injected CO2 has been stored in the reservoir with the rest of injected CO2 breakthrough in the production wells. CO2 storage safety needs more detailed and comprehensive monitoring data for further verification. The obtained preliminary monitoring experience can provide valuable guidance for the future enlarged Jilin project and other CO2 EOR and storage operations.