Supercritical CO2 intrusion into caprocks: experimental observations and numerical simulations

Geologic storage of carbon dioxide (CO2), mainly in deep saline aquifers, has emerged as a key solution to reach the Paris Agreement goal of limiting the global temperature increase below 2ºC and effectively mitigate climate change. The injected CO2 is less dense at the storage condictions than the resident brine and tends to flow upward by buoyancy. Therefore, to achieve the primary objective of permanently storing CO2 underground during geological time scales, the host reservoir should be overlain by a low-permeability and high-entry pressure caprock that prevents CO2 escaping from the storage formation. Meanwhile, the caprock sealing capacity is of particular significance and yet to be assessed in more detail. In this presentation, we aim at shedding light on the flow processes governing potential CO2 leakage through shaly caprocks by combining experimental observations and numerical simulations. We present breakthrough experiments on Opalinus Clay, which is a representative caprock for CO2 storage. These experiments reproduce supercritical CO2 intrusion and flow through the caprock sample under representative reservoir conditions. Next, we address numerical simulation of the breakthrough experiments using a twophase flow model in deformable porous media to provide a mechanistic interpretation of experimental observations. Overall, we conclude that CO2 leakage through the caprock is dominated by molecular diffusion rather than by rapid bulk volumetric advection.

Bibliographic Details

Main Authors:	Rahimzadeh Kivi, I., Vilarrasa, Víctor, Makhnenko, R.
Other Authors:	Vilarrasa, Víctor [0000-0003-1169-4469]
Format:	material didáctico biblioteca
Language:	English
Published:	2021-01-21
Subjects:	Geologic carbon storage, Caprock, CO2,
Online Access:	http://hdl.handle.net/10261/246835
Tags:	Add Tag No Tags, Be the first to tag this record!