Hydrogeochemical Modeling for Natural Analogue Study of CO2 Leakage due to Matsushiro Earthquake Swarm

ABSTRACTThe use of sediment laid down in a Scottish loch during the Flandrian marine transgression as a source term for a “natural analogue” study of elemental migration in clays over a timescale of 103 − 104 y has been investigated. Depth profiles of over 20 elements have been measured which illustrate varying post depositional behaviour ranging from effectively total immobility to complete redistribution throughout the sediment profile. These results are contrasted with laboratory batch sorption data for a range of nuclides on samples of this sediment.

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Microscale Research on Effective Geosequestration of CO2 in Coal Reservoir: A Natural Analogue Study in Haishiwan Coalfield, China

Geofluids ◽

10.1155/2018/3015038 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Kaizhong Zhang ◽

Wei Li ◽

Yuanping Cheng ◽

Jun Dong ◽

Qingyi Tu ◽

...

Keyword(s):

Oil Shale ◽

Strong Support ◽

Natural Analogue ◽

Geological Time ◽

Reservoir Properties ◽

Long Term Storage ◽

Analogue Study ◽

Before And After ◽

Seepage Channel ◽

Coal Reservoir

A natural analogue study in CO2-rich coalfield (Haishiwan, China) provides a strong support for safe, reliable, and long-term storage by analyzing the mechanism of CO2 migration, entrapment, and storage in coal reservoir. Thus, effects of geological tectonism on reservoir properties were investigated. Simultaneously, coal and oil shale samples before and after supercritical CO2 (SCCO2) treatment via geochemical reactor were collected to analyze changes in pore structure, functional group distributions, and SCCO2 extraction. Observations from in situ properties of coal seam indicate that there is a positive relationship with CH4 contents and F19 fault whereas CO2 and carbonate contents decrease as the distance from F19 increases. Analysis of pore properties reveals that SCCO2 enlarges the development of coal pore and facilitates the diffusion and seepage channel of coal reservoir, while no changes in larger pores are found in oil shale, which may restrain fluids from passing through. Then, oxygen-containing functional groups are mobilized by SCCO2 from oil shale, associated with a decrease in sorption sites. The sealing capacity of cap rock (oil shale) and geological tectonism (F19 fault), as the major contributors to CO2 enrichment and accumulation, provides insights into the suitable selection of CCGS site for long geological time.

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Reaction of bentonite in low-alkali cement leachates: an overview of the Cyprus Natural Analogue Project (CNAP)

Mineralogical Magazine ◽

10.1180/minmag.2012.076.8.17 ◽

2012 ◽

Vol 76 (8) ◽

pp. 3019-3022 ◽

Cited By ~ 2

Author(s):

W. R. Alexander ◽

A. E. Milodowski ◽

A. F. Pitty ◽

S. M. L. Hardie ◽

S. J. Kemp ◽

...

Keyword(s):

Critical Path ◽

Series Data ◽

Reaction Products ◽

Natural Analogue ◽

Rock Interaction ◽

Analogue Study ◽

Bentonite Buffer ◽

Slow Kinetics ◽

Decay Series ◽

Natural Decay

AbstractThe Cyprus Natural Analogue Project was carried out due to the requirement to support ongoing laboratory and modelling efforts on the potential reaction of the bentonite buffer with cementitious leachates in the repository engineered barrier system. Although it is known that the higher pH (12.5–13) leachates from ordinary Portland cement will degrade bentonite, it is unclear if this will also be the case for the lower pH (10–11) leachates typical of low alkali cements. Ongoing laboratory and underground rock laboratory programmes, which are currently investigating this, face the obstacle of slow kinetics and the production of short-lived metastable phases, meaning obtaining unambiguous results may take decades. It was therefore decided to implement a focussed natural analogue study on bentonite/low alkali cement leachate reactions to provide indications of the probable long-term reaction products and reaction pathways to provide feedback on the existing short-term investigations noted above and to ascertain if any critical path research and development needs to be instigated now. The results of the analyses presented here, in this short overview of the project, suggest that there has been very limited alkaline groundwater reaction with the bentonite. This is generally supported by both the geomorphological evidence and the natural decay series data which imply groundwater/rock interaction in the last 105 a.

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