Experimental observation of permeability changes in dolomite at CO2 sequestration conditions.

Injection of cool CO2 into geothermally warm carbonate reservoirs for storage or geothermal energy production may lower near-well temperature and lead to mass transfer along flow paths leading away from the well. To investigate this process, a dolomite core was subjected to a 650 h, high pressure, CO2 saturated, flow-through experiment. Permeability increased from 10(-15.

Permeability reduction produced by grain reorganization and accumulation of exsolved CO2 during geologic carbon sequestration: a new CO2 trapping mechanism.

Carbon sequestration experiments were conducted on uncemented sediment and lithified rock from the Eau Claire Formation, which consisted primarily of K-feldspar and quartz. Cores were heated to accentuate reactivity between fluid and mineral grains and to force CO(2) exsolution. Measured permeability of one sediment core ultimately reduced by 4 orders of magnitude as it was incrementally heated from 21 to 150 °C.

Classification of thermal patterns at karst springs and cave streams.

Thermal patterns of karst springs and cave streams provide potentially useful information concerning aquifer geometry and recharge. Temperature monitoring at 25 springs and cave streams in southeastern Minnesota has shown four distinct thermal patterns. These patterns can be divided into two types: those produced by flow paths with ineffective heat exchange, such as conduits, and those produced by flow paths with effective heat exchange, such as small fractures and pore space.