The earth environment that human beings rely on is seriously threatened by air pollution and global climate change caused by massive CO2 emissions into the atmosphere. Several studies show that geological storage is an effective way to dispose of CO2. Most oilfields in China have entered middle and late development stages, and a great proportion of them are suitable for CO2-EOR and carbon storage. Enormous economic and social benefits could be brought about by applying CO2-EOR technologies in these oilfields. Therefore, the objective of this paper is to systematically screen, assess, and sort the oilfields in China for their suitability for CO2-EOR and assess potential economic and social benefits for implementing CO2-EOR.
First, the screening criteria of the reservoirs suitable for CO2-EOR used in previous studies by many experts were summarized. Second, the screening of Chinese oilfields suitable for CO2-EOR was first executed based on these screening criteria. Then, a comprehensive assessment and sorting of reservoirs suitable for CO2-EOR was carried out using the fuzzy analytic hierarchy process (FAHP) method. Finally, potential economic and social benefits due to CO2-EOR in China were assessed.
Based on data from 511 onshore oilfields in China, the screening result indicates that 151 oilfields are suitable for CO2 miscible flooding and 1 oilfield is suitable for CO2 immiscible flooding. Using the fuzzy analytic hierarchy process method, the 152 oilfields were synthetically assessed and sorted and their potential benefits were evaluated. Using enhanced oil recovery from 5% to 20%, the resulting incremental production could be 3.45×108t to 13.81×108t, respectively, and the CO2 storage potential could be 8.55×108t to 34.19×108t. Total potential economic benefits could reach $76.15 billion to $710.75 billion, CO2 emission reduction benefits could be $0.35 billion to $64.27 billion, energy security benefits could be $0.84 billion to $3.35 billion, and the total benefits could reach $77.34 billion to $778.37 billion. The implementation of CO2-EOR in China could greatly contribute to the Chinese economy and carbon reduction commitment.
This study conducted a survey of the suitability of Chinese oilfields for CO2 EOR, evaluated and sorting the suitability of different oilfields comprehensively and finally calculated the potential economic and social benefits. This study will provide a foundation for the implementation of a CO2-EOR program in China.