Speaker
Description
The injection of CO2 into saline water-bearing formations for long-term carbon capture and underground storage (CCS) alters the subsurface mineral stability and can lead to the alteration of reactive minerals prior to long-term mineralization. We simulate how the alteration of reactive cements in Morrow B and Entrada sandstone changes different facies’ absolute permeability by combining X-ray computed tomography (XRCT) 3D models of pre- and post-experiment samples and single phase Lattice Boltzmann (LB) simulations. The LB simulations are placed in an iterative framework where microporosity of reactive facies is varied until the continuum-scale changes in permeability are matched. Both the Morrow B and Entrada Formations are targets for long-term CCUS. Both formations have been separated into different hydraulic flow units (HFU). The Entrada Formation has relatively few units (< 3), but the Morrow B formation has been broken into between five and eight HFUs, defined by pore size distribution as quantified by mercury porosimetry. In both cases, the pore size distribution is correlated with depositional microenvironment and cementation. Flow-through experiments at reservoir conditions were conducted on each HFU, with one experiment with formation water only and two tests at different flow rates with formation water at 66-77% CO2 saturation. Very small changes in porosity (often <1-2% absolute change) via reactive cement dissolution were observed. Permeability changes in CO2-reacted samples ranged from decreases within the same magnitude to increases of more than an order of magnitude. XRCT (10 um voxel resolution) analysis was performed, and porosity and microporous facies were thresholded from the data. Using the solid/microporous/pore voxels from XRCT analysis, we simulated flow using single relaxation time, single phase Lattice Boltzmann on the Palabos platform for the least and the most altered samples to (a) understand how minor dissolution and precipitation of minerals lead to HFU-level changes in permeability, and (b) provide an iterative way of scaling pore scale simulations to the continuum scale changes in permeability.
Funding for this project is provided by the U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) through the Southwest Regional Partnership on Carbon Sequestration (SWP) under Award No. DE-FC26-05NT42591. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
| Country | USA |
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