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Title: CO2 Leakage Into Shallow Aquifers: Modeling CO2 Gas Evolution and Accumulation at Interfaces of Heterogeneity

The physicochemical processes associated with CO2 leakage into shallow aquifer systems are complex and span multiple spatial and time scales. Continuum-scale numerical models that faithfully represent the underlying pore-scale physics are required to predict the long-term behavior and aid in risk analysis regarding regulatory and management decisions. This study focuses on benchmarking the numerical simulator, FEHM, with intermediate-scale column experiments of CO2 gas evolution in homogeneous and heterogeneous sand configurations. Inverse modeling was conducted to calibrate model parameters and determine model sensitivity to the observed steady-state saturation profiles. It is shown that FEHM is a powerful tool that is capable of capturing the experimentally observed out ow rates and saturation profiles. Moreover, FEHM captures the transition from single- to multi-phase flow and CO2 gas accumulation at interfaces separating sands. We also derive a simple expression, based on Darcy's law, for the pressure at which CO2 free phase gas is observed and show that it reliably predicts the location at which single-phase flow transitions to multi-phase flow.
Authors:
 [1] ;  [2] ;  [3] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Earth System Observations
  2. Colorado School of Mines, Golden, CO (United States). Center for Experimental Study of Subsurface Environomental Processes
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computational Earth Sciences
OSTI Identifier:
1246338
Report Number(s):
LA-UR--14-28232
Journal ID: ISSN 1876-6102; PII: S1876610214021675
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Energy Procedia
Additional Journal Information:
Journal Volume: 63; Journal Issue: C; Journal ID: ISSN 1876-6102
Publisher:
Elsevier
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES