溶解性が形成水に閉じ込められるのは,天然ガス田の支配的なCO2沈殿地であるためである
Stuart M V Gilfillan1, Barbara Sherwood Lollar, Greg Holland
1School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK. stuart.gilfillan@ed.ac.uk
Nature
|April 3, 2009
まとめ
二酸化炭素 (CO2) の地質学的貯蔵は,CO2の運命を理解することに依存しています. 天然ガスの鉱床は,CO2が主に形成水に溶け,鉱物降水が軽微な役割を果たしていることを示しています.
科学分野:
- 地質化学 地質化学
- 環境科学 環境科学
- 地質学 地質学 地質学
背景:
- 深い地質層に二酸化炭素 (CO2) を注入することは,工業的な炭素の捕獲と貯蔵のための重要な戦略です.
- 注入されたCO2の長期的運命を評価することは,現場の設計と安全モデリングに不可欠ですが,短期的な観測から決定することは困難です.
研究 の 目的:
- 天然ガス田におけるCO2の流体相からの除去の主なメカニズムを特定し,定量化する.
- これらの天然の類型を用いて,人類によるCO2の貯蔵の長期的振る舞いを,千年にわたる時間スケールで予測する.
主な方法:
- 北米,中国,欧州の9つの天然ガス田における貴重ガスと炭素同位体の分析.
- 地質学的貯蔵条件をシミュレートするために,自然にCO2相が支配するフィールドの調査.
主要な成果:
- 研究された9つの分野のうち7つの分野 (シリシクラスティックまたは炭酸塩石質学) で,形成水 (pH 5-5.8) でのCO2溶解が支配的な除去メカニズムでした.
- 2つのシリシクラスティックフィールドでは,炭酸塩鉱物の降水が最大18%のCO2損失を構成しており,これは小規模な捕獲メカニズムであることを示している.
結論:
- 地質学的鉱物固定は,研究された天然ガス田でCO2を捕まえる小さなメカニズムである.
- 同様の地質学的システムにおける人為的なCO2貯蔵の長期的なモデルは,形成水中の溶けたCO2の潜在的移動性を優先すべきである.
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