QUANTIFYING MICROTEXTURAL CONTROLS ON CHANGES IN ABSOLUTE PERMEABILITY DURING FLUID-ROCK INTERACTIONS USING LATTICE BOLTZMANN SIMULATIONS OF XRCT-MEASURED SANDSTONE PORE NETWORKS

The injection of CO2 into saline water-bearing formations for long-term carbon capture and underground storage (CCUS) to mitigate anthropogenic climate change drives the alteration and precipitation of minerals. We simulate how the alteration of reactive cements in Morrow B 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 simulations. The Morrow B sandstone in the Farnsworth Unit of North Texas is the site of enhanced oil recovery and CCUS operations. The sandstone has been classified into five hydraulic flow units (HFU) defined by pore size distribution and permeability, correlated with complicated 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 understand how minor dissolution and precipitation of minerals lead to HFU-level changes in permeability. XRCT imaging of reservoir rocks with a qualitative understanding of reactive phases may provide a path to forecast injectivity changes.

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.