Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-0754, United States.
Environ Sci Technol. 2011 Aug 1;45(15):6676-82. doi: 10.1021/es201279e. Epub 2011 Jul 14.
Microorganisms can strongly influence the chemical and physical properties of the subsurface. Changes in microbial activity caused by geological CO(2) storage, therefore, have the potential to influence the capacity, injectivity, and integrity of CO(2) storage reservoirs and ultimately the environmental impact of CO(2) injection. This analysis uses free energy calculations to examine variation in energy available to Fe(III) and SO(4)(2-) reducers and methanogens because of changes in the bulk composition of brine and shallow groundwater following subsurface CO(2) injection. Calculations were performed using data from two field experiments, the Frio Formation experiment and an experiment at the Zero Emission Research and Technology test site. Energy available for Fe(III) reduction increased significantly during CO(2) injection in both experiments, largely because of a decrease in pH from near-neutral levels to just below 6. Energy available to SO(4)(2-) reducers and methanogens varied little. These changes can lead to a greater rate of microbial Fe(III) reduction following subsurface CO(2) injection in reservoirs where Fe(III) oxides or oxyhydroxides are available and the rate of Fe(III) reduction is limited by energy available prior to injection.
微生物可以强烈影响地下的化学和物理性质。因此，由于地质 CO(2)储存引起的微生物活动的变化有可能影响 CO(2)储存储层的容量、注入能力和完整性，并最终影响 CO(2)注入的环境影响。本分析使用自由能计算来研究由于地下 CO(2)注入后卤水和浅层地下水的总体组成发生变化，Fe(III)和 SO(4)(2-)还原剂和产甲烷菌可用能量的变化。计算使用来自两个现场实验的数据(Frio 组实验和零排放研究和技术测试场的实验)进行。在两个实验中，CO(2)注入期间 Fe(III)还原的可用能量显著增加，主要是由于 pH 值从接近中性水平降至略低于 6。SO(4)(2-)还原剂和产甲烷菌的可用能量变化不大。这些变化可能导致在储层中微生物 Fe(III)还原的速率增加，这些储层中存在 Fe(III)氧化物或氢氧化物，并且在注入之前可用能量限制 Fe(III)还原的速率。
