CO2 storage safety and leakage monitoring in the CCS demonstration project of Jilin oilfield, China. Issue 4 (20th February 2014) - Zhang, Liang
Abstract Jilin oilfield is conducting the first large‐scale demonstration project on CO2 storage and enhanced oil recovery (EOR) in the northeast of China. A comprehensive monitoring program has been designed and deployed in the target reservoir of block H‐59 using a wide range of techniques to monitor the injection and production systems, the CO2 migration fronts, and potential CO2 leakage pathways. Tube fault detection, corrosion inhibitors, anti‐CO2 corrosion cement, and production dynamic analysis have been adopted to guarantee the safety at the well site. CO2 movement in the reservoir is detected mainly by gas tracer, electric spontaneous potential measurement, and fluid sampling. Near‐surface environmental monitoring is also conducted around the injection site. Field experience has shown that the monitoring targets should be focused on the reservoir, near‐surface, and injection and production systems. Applying monitoring techniques to ensure the integrity of wellbores can not only prevent the leakage of CO2, but also avoid the blind expansion of monitoring program scopes. It is reliable and economical to take full advantage of techniques based on wellbores to monitor CO2 movement in oil reservoirs with dense well patterns. Up to April 2013, nearly 21.7 × 104 tons of CO2 has been injected without obvious leakage caused by integrity failure of wells or the geological structure of reservoir. More than 96% of injected CO2 has been safely stored with the rest of injected CO2 normally breakthrough in the production wells. The preliminary monitoring experience obtained can provide valuable guidance for the future enlarged Jilin project and other CO2 EOR and storage operations.