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Abstract
The Moxa Arch Anticline is a regional-scale northwest-trending uplift in
western Wyoming and it has been chosen for CO2 capture and storage. The Nugget
Sandstone is a deep saline aquifer that has been a candidate for CO2 storage.
In this paper we compare the amount of mineral and solution trapping in
comparison with dynamic hysteresis trapping based on compositional simulation.
To the best of our knowledge this is the first paper to computationally assess
the chemical trapping in the Nugget formation and to compare these three
trapping mechanisms against each other.
Reaction-path and kinetic modeling of CO2–brine–mineral reactions in the Nugget
formation was investigated to probe the factors that affect capacity for CO2
chemical trapping. The geochemical simulation of this system was explored in
order to assess how mineralogy might change and the relative importance of
mineral and solution trapping phenomena through time. Mineral trapping is
simulated with both GWB and GEM-GHG. The maximum mineral trapping is 5 g of CO2
per ton of reacted rock, and solution trapping is 3.47 g/kg rock. In
comparison, a recent computational study of the Rose Run sandstone, Ohio
indicates a much higher mineral trapping capacity, mainly because of reservoir
pressure in addition to the presence of glauconite as an iron source for
siderite formation.
These results reveal that mineral trapping in the Nugget formation is not
significant but that total chemical trapping might be much more than that of
hysteresis trapping. Therefore, the contribution and importance of chemical
trapping in CO2 sequestration should be taken into account for assessment of
CO2 sequestration.
Introduction
This paper is extension to our former paper, SPE 132447. Much deeper depth is
targeted here and also all trapping mechanisms are integrated in one simulator
which means we can see the effect of different trapping mechanisms on each
other. In addition, simulated mineral trapping with GEM-GHG, multiphase flow
simulator, is compared with results of GWB, single phase simulator. CO2
sequestration is becoming one of the hot topics cross all disciplines. Most of
countries in the world are spending large amount of money to investigate CO2
sequestration feasibility and shortcomings e.g. cap rock leakage. Underground
formation became the target for CO2-sequestraion such as abundant oil and gas
fields, coal bed methane and saline aquifer. The saline aquifers have the
maximum capacity. For instance in North America, saline aquifers capacity is
8±4 Billion metric tons, around 94% of total capacity while the mature
hydrocarbon reservoirs has 4% of total capacity (DOE and NETL, Carbon and
Sequestration Atlas for the USA and Canada, 2008). All saline aquifers which
have salinity above 10000 ppm are acceptable for CO2-sequestration based on
U.S. Environmental Protection Agency. There have been a lot of researches on
CO2-Sequestration in last decades all over the world; The Netherlands (Lohuis,
1993), Alberta basin, Canada (Bachu et al., 1994; Gunter et al., 2004; Cantucci
et al., 2009), North Sea (Korbol and Kaddour, 1995) and USA (Zerai et al.,
2006; Han et al., 2009).
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