Effect of injected CO2 on geochemical alteration of the Altmark gas reservoir in Germany

摘要: Capturing CO2 from point sources and storing it in geologic formations is a potential option for allaying the level atmosphere. In order to evaluate effect of geological storage on rock-water interaction, batch experiments were performed sandstone samples taken Altmark reservoir, Germany, under situ conditions 125 °C 50 bar partial pressure. Two sets pulverized sample material placed inside closed reactor (a) saturated (b) free environment 5, 9 14 days. A 3M NaCl brine was used both cases mimic reservoir formation water. For “CO2 free” environment, Ar as pressure medium. The mainly composed quartz, feldspars, anhydrite, calcite, illite chlorite minerals. Chemical analyses liquid phase suggested dissolution calcite anhydrite cases. However, more pronounced presence CO2. addition, enhanced feldspar Solid analysis by X-ray diffraction Mossbauer spectroscopy did not show any secondary mineral precipitation. Moreover, evidence significant changes redox conditions. Calculations total dissolved solids’ concentrations indicated that extent factor approximately 1.5 during injection CO2, which might improve injectivity capacity targeted reservoir. experimental data provide basis numerical simulations injected long-term geochemical alteration at scale.