CO2 Trapping State in Saline Aquifers and its Implications for Site-scale Storage Capacity Assessment
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- 作者：Yiman Li ; liyiman@mail.iggcas.ac.cn ; Zhonghe Pang
- 关键词：CO2 trapping state ; site-scale ; Guantao formation ; storage capacity assessment method ; carbon-13 and oxygen-18
- 刊名：Procedia Earth and Planetary Science
- 出版年：2017
- 出版时间：2017
- 年：2017
- 卷：17
- 期：Complete
- 页码：488-491
- 全文大小：135 K
- 卷排序：17
文摘
Final trapping state of CO2 in the formation water is key to site selection and long-term safety for commercial scale CO2 geological storage projects. CO2 trapping mechanisms in deep saline aquifers and contribution percentages of different trapping states are reviewed. CO2 will be trapped in free gas state, soluble state and mineral state ultimately once being injected and mineral state can only be effective on the timeframe of tens of thousands of years. For pilot and commercial scale CO2 sequestration projects, site scale CO2 storage capacity assessment with timeframe of a hundred to a thousand year is practical and CO2 trapped in mineral state can be ignored. Assessing methods for CO2 stored in free gas state and soluble state are proposed in the paper based on pH changes, carbon-13 and oxygen -18 isotope exchanges between formation water and injected CO2. Using the suggested methods and water chemistry and isotopic data from experiments and field test for Neogene Guantao and Minghuazhen formations, CO2 stored in soluble state are calculated to be 12.5 g/kgw and 0.22 g/kgw while CO2 stored in free gas state takes 23∼36% of the effective pore volume.