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Communication dans un congrès

Both experimental study and numerical modelling of the effect of temperature gradient on CO2 injection

Abstract : CO2 injection and underground storage obviously requires dealing with temperature differences between the injection well and the reservoir. Temperature enhances both species transport and reactions kinetics, while CO2 solubility also greatly decreases with temperature. This point could be of great importance especially in wellbore surroundings, although it has not been the subject of devoted studies up to now. To assess this issue, an experimental set up, COTAGES, has been designed (Fig.1). It consists in a 0.72m-long cylindrical autoclave (the diameter is 2.1cm) that can be filled with 12 fiberglass/teflon packets containing 12.5 grams of mineral grains and a pre-equilibrated saline aqueous solution. When loaded, one end of the autoclave is heaten up and maintained at 100°C. After having reached a steady-state, the other end is around 30°C. Finally, CO2 is injected in the cold zone (100 bars) and, from this moment, the experiment lasts 1 month while both pressure and temperatures (3 zones) are being monitored. The first results show the same general trend for both a reservoir rock such as oolitic limestone (Lavoux, France) and clay minerals such as COx argillite (Lundin, France). In these two experiments, a global mass loss is observed for all the packets except for those comprised between 75 and 95°C. There, a mass gain is noted and is remarkably important in the case of clay (greater than 11.5%). The greater losses are recorded around 65-70°C and are also of greater importance for COx clay (up to 10.0%). During the whole experiments, quite important variations of the total pressure are observed. Even if they are partly related to CO2 dissolution into water and to temperature variations (due to regulation), they shall also depend on involved chemical reactions. Indeed, after injection, pressure drastically decreases (up to 50 bar less). Since CO2 solubility is higher in the cold zone (more than 4 times), the aqueous solution gets more acidic there. It leads to a more important carbonates dissolution, thus to increases of CO2 fugacity and consequently of the global pressure. Furthermore, the calcium content tends to be greater in this cold-dissolution zone then Ca diffuses towards the hotter zone locally and it implies calcite precipitation. As evidence of this phenomenon, plugs, related to massive calcite precipitation, are observed in these regions and newly crystallized calcite can be seen on SEM images. In order to clearly understand the reasons of the observed behaviour, numerical computations performed with the reaction-transport code HYTEC have to be run. Several scenarios can thus be simulated to check various assumptions. Firstly, different initial repartitions of the CO2 can be tested: in some kind of reservoir in the cold/injection zone or everywhere in the autoclave (due to high initial pressure gradient). Secondly, the competition between the implied processes, their respective kinetics and their temperature dependance can be assessed too: thermodynamics and/or kinetics of chemical reactions and transport kinetics (diffusion). Modeling becomes then of great help to interpret the experimental results and even to better design the evolution of the experimental set-up.
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https://hal-mines-paristech.archives-ouvertes.fr/hal-00634846
Contributeur : Jérôme Corvisier <>
Soumis le : lundi 24 octobre 2011 - 10:17:51
Dernière modification le : mercredi 14 octobre 2020 - 03:52:22
Archivage à long terme le : : mercredi 25 janvier 2012 - 02:25:12

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corvisier2010-agu.pdf
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  • HAL Id : hal-00634846, version 1

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Jérôme Corvisier, Vincent Lagneau, Emmanuel Jobard, Jérôme Sterpenich, Jacques Pironon. Both experimental study and numerical modelling of the effect of temperature gradient on CO2 injection. American Geophysical Union, Dec 2010, San Francisco, United States. ⟨hal-00634846⟩

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