Natural Gas Storage in Basalt Aquifers of the Columbia Basin, Pacific Northwest USA: A Guide to Site Characterization

Abstract

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Geological, geochemical and social-scientific assessment of basaltic aquifers as potential storage sites for CO2

“…In the present study, we estimate the capacity of the Deccan Traps, Siberian Traps, Ethiopian Flood Basalts, Parana Flood Basalts and Icelandic Basalt, in addition to the CRBG, using assumptions similar to those of McGrail et al (2006) (average porosity, 15%; net aquifer thickness from 10 m, one available interflow zone, to 100 m, 10 available interflow zones). McGrail et al (2006) assumed a net aquifer thickness of 100 m (10 available interflows, each one 10 m thick), based on the research of Reidel et al (2002). In this study, however, we assumed a net aquifer thickness from 10 m to 100 m. Because flood basalts consist of tens to hundreds of individual lava flows and the thickness of a typical target formation is about 200 m (depth from 800 to 1000 m), in the minimum case, it is possible for there to be only one available interflow zone and for the net thickness of the target aquifer to be only 10 m.…”

The new Wallula CO2 project may revive the old Columbia River Basalt (western USA) nuclear-waste repository project

“…The high-porosity tops of basalt flows are attractive targets for underground storage projects, not only for nuclear waste but also for natural gas (Reidel et al 2002) and carbon dioxide (McGrail et al 2011(McGrail et al , 2014McGrail and Schaef 2015;Matter et al 2016). The reasons for the attractiveness, of course, are different.…”

“…Consider that a carbon-dioxide injection project in the CRB can be seen as a hydrology data collection event with a built-in time accelerator, which is convenient for projections concerning groundwater and nuclear waste disposal. The case of the deep CRB groundwater is especially interesting because it is very old: >30,000 years or even >100,000 years according to 14 C or helium data, respectively (Reidel et al 2002). Chemically, the old groundwaters are characterised by high pH as well as high sodium and fluoride concentrations, whereas calcium and magnesium concentrations are low.…”

“…Chemically, the old groundwaters are characterised by high pH as well as high sodium and fluoride concentrations, whereas calcium and magnesium concentrations are low. Both the Hanford Reference Repository and the Wallula CO 2 injection zone (Table 1) are in typical deep CRB groundwater (Reidel et al 2002;McGrail et al 2009;Lavalleur 2012), where formation temperature ranges from 37 to 54°C.…”

“…The low-Eh and low-pH side of the native-copper stability field is the copper-sulphide phase boundary (CuS and CuS 2 ). The position of this boundary depends on the total activity of aqueous sulphur species (ΣS), which is ≤1.5 × 10 −3 in CRB groundwater (Grande Ronde Basalt Formation; Reidel et al 2002). Provided the bentonite backfill contains no sulphur-bearing minerals, the corrosion of the copper container is constrained by the diffusion of aqueous sulphide from the igneous rock aquifer through the bentonite to the container surface.…”