# A Review of Recent Progress of Carbon Capture, Utilization, and Storage (CCUS) in China
## 4 Progress of CO\({}_{2}\) Utilization in China
### Development Status of CO\({}_{2}\) Geological Utilization in China
#### 4.3.1. \(\mathrm{CO}_{2}\)-Enhanced Oil Recovery (\(\mathrm{CO}_{2}\)-EOR) in China  
CO\({}_{2}\)-EOR is injecting CO\({}_{2}\) into the reservoir to modify the flow characteristics of the multiphase fluid in porous media, including interfacial tension reduction, oil viscosity reduction and oil permeability improvement, thereby enhancing oil recovery [113]. CO\({}_{2}\)-EOR is applicable to both conventional and unconventional reservoirs with low or ultra-low permeability. China's CO\({}_{2}\)-EOR technologies and apparatus are extremely advanced because CO\({}_{2}\) flooding research and applications have been carried out in China since the 1960s [97]. Currently, China's CO\({}_{2}\)-EOR has already progressed to the stage of industrial demonstration. The annual CO\({}_{2}\) utilization scale for EOR is approximately 1.54 million tonnes, and the cumulative CO\({}_{2}\) storage has exceeded more than 660 \(\times\) 10\({}^{4}\) tonnes [83], still demonstrating considerable potential. The distribution of CO\({}_{2}\) emission sources and the geological characteristics need to be considered when selecting the location for CO\({}_{2}\)-EOR projects. China's iron and steel enterprises are mainly distributed in the east and north, and the large amount of CO\({}_{2}\) emissions produced during the steel production process can serve as the CO\({}_{2}\) source for CO\({}_{2}\)-EOR projects. For the basins that are also located in the east and north of China, such as the Ordos Basin, Songliao Basin, and Bohai Bay Basin, there is a shorter CO\({}_{2}\) transport distance between the CO\({}_{2}\) emission sources and these basins, namely, good spatial matching. Therefore, these basins are regarded as priority areas for China's CO\({}_{2}\)-EOR project implementation [50] due to the substantial advantage of good spatial matching. For the Tarim Basin and Junggar Basin situated in the northwest of China, although there are fewer CO\({}_{2}\) emission sources nearby, they are still considered to be appropriate areas for CO\({}_{2}\)-EOR projects due to their favorable geological characteristics and high geological storage capacities. Due to the close integration of CO\({}_{2}\) with oil production in CO\({}_{2}\)-EOR, most of the CO\({}_{2}\)-EOR projects in China are undertaken by oil companies, including CNPC, Sinopec, and Shaanxi Yanchang Petroleum. By 2021, there are nine major CO\({}_{2}\)-EOR projects in operation. The CNPC Jilin oilfield CO\({}_{2}\)-EOR project is currently the largest CCUS project in Asia, and it is also the only project in China among the 21 large CCUS projects currently operating across the world. It adopts pre-combustion capture combined with associated gas separation technology and pipeline transport, with a CO\({}_{2}\) injection capacity of 60 \(\times\) 10\({}^{4}\) tonnes/year [50] and an oil production capacity of approximately 10 \(\times\) 10\({}^{4}\) tonnes/year [83]. The cumulative CO\({}_{2}\) storage has reached 2.12 million tonnes since it was put into operation in 2008 [83]. Another representative national demonstration project in China is the Daqing Oilfield CO\({}_{2}\)-EOR project. It adopts the pre-combustion method to capture CO\({}_{2}\) generated from natural gas processing and uses a combination of tanker truck and pipeline for CO\({}_{2}\) transport, realizing CO\({}_{2}\) injection of 30 \(\times\) 10\({}^{4}\) tonnes/year and oil production of 10 \(\times\) 10\({}^{4}\) tonnes/year [83]. The current CO\({}_{2}\)-EOR projects in China are listed in Table 6. According to the results of CO\({}_{2}\)-EOR in Jilin and Daqing oilfields, oil recovery can be enhanced by 10-25% through CO\({}_{2}\)-EOR, that is, approximately 1.0 tonnes of oil increment for every 2.0-3.0 tonnes of CO\({}_{2}\) injection, indicating obvious advantages in oil increment and CO\({}_{2}\) storage [83].