Solubility trapping in formation water as dominant CO2 sink in natural gas fields
Solubility trapping in formation water as dominant CO2 sink in natural gas fields
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DOI：
10.1038/nature07852
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发表时间：
2009-04-02
期刊：
影响因子：
64.8
通讯作者：
Ballentine, Chris J.
中科院分区：
文献类型：
--
作者：
Gilfillan, Stuart M. V.;Lollar, Barbara Sherwood;Ballentine, Chris J.
将CO2注入深层地质层被提议作为一种安全和经济上有利的储存从工业点源捕获的CO2的手段（1-3）。然而，根据对现有处置场的十年观测结果，很难评估地下CO2泛滥的长期后果（1，2）。场地设计和长期安全建模都主要取决于CO2在场地寿命期间的储存方式和地点（2-4）。在地质储存场内，注入的二氧化碳可以溶解在溶液中或沉淀为碳酸盐矿物。在这里，我们确定和量化的主要机制，在北美，中国和欧洲的9个天然气田的CO2流体相去除，使用惰性气体和碳同位素示踪剂。在我们的研究中调查的天然气田主要由CO2相，并提供了一个自然的模拟评估的地质存储人为CO2在千年的时间尺度（1，2，5，6）。我们发现，在7个气田与硅质岩或碳酸盐岩为主的储层岩性，溶解在地层水中的pH值为5-5.8是唯一的主要汇CO2。在具有硅质岩储层岩性的两个油田，不能排除通过作为碳酸盐矿物的降水损失一些CO2，但最多可占就位CO2损失的18%。鉴于我们的研究结果，地质矿物固定是一个小的CO2捕集机制，在天然气田，我们建议，长期人为CO2储存模型在类似的地质系统应侧重于潜在的流动性溶解在水中的CO2。
Injecting CO2 into deep geological strata is proposed as a safe and economically favourable means of storing CO2 captured from industrial point sources(1-3). It is difficult, however, to assess the long-term consequences of CO2 flooding in the subsurface from decadal observations of existing disposal sites(1,2). Both the site design and long-term safety modelling critically depend on how and where CO2 will be stored in the site over its lifetime(2-4). Within a geological storage site, the injected CO2 can dissolve in solution or precipitate as carbonate minerals. Here we identify and quantify the principal mechanism of CO2 fluid phase removal in nine natural gas fields in North America, China and Europe, using noble gas and carbon isotope tracers. The natural gas fields investigated in our study are dominated by a CO2 phase and provide a natural analogue for assessing the geological storage of anthropogenic CO2 over millennial timescales(1,2,5,6). We find that in seven gas fields with siliciclastic or carbonate-dominated reservoir lithologies, dissolution in formation water at a pH of 5-5.8 is the sole major sink for CO2. In two fields with siliciclastic reservoir lithologies, some CO2 loss through precipitation as carbonate minerals cannot be ruled out, but can account for a maximum of 18 per cent of the loss of emplaced CO2. In view of our findings that geological mineral fixation is a minor CO2 trapping mechanism in natural gas fields, we suggest that long-term anthropogenic CO2 storage models in similar geological systems should focus on the potential mobility of CO2 dissolved in water.