Geologic heterogeneity controls on CO₂ migration and trapping

In this dissertation, we study the influence of small-scale geologic heterogeneities (mm to dm) on buoyant, vertical migration of CO₂ at intermediate length scales (sub-meter) in two different ways: using numerical simulations in highly resolved geologic models, and by visualizing flow through lab generated bedform fabrics. In the first part of this dissertation, we present a new technique to generate high resolution, 3D geocellular models that capture depositional architectures in a realistic manner. We then use a reduced physics formulation (Invasion Percolation) to simulate the migration of CO₂ through the developed models. Results from these simulations provide insight into how the trapped saturation is a non-linear function of the capillary entry pressure contrast between the primary lithologic features. This dependence suggests that some ability to predict CO₂ storage performance can be achieved from common sedimentological descriptors. In the second half, we develop a unique experimental technique to generate intermediate scale (0.6m x 0.6m) beadpacks that mimic natural sedimentary features in a reproducible manner. We then perform a set of two-phase flow experiments in heterogeneous beadpacks with cross-stratified geometry, where the underlying geometry is kept constant but the grain size contrast is varied, analogous to our simulations. The experiments are conducted at atmospheric conditions using an immiscible fluid pair that mirrors the physical properties of supercritical CO₂ and brine at reservoir conditions. Light transmission is used to visualize the flows in real time and quantify fluid saturations at the millimeter scale. Observations from these experiments help corroborate our simulation results, showing that geometry and grain size variability strongly influence CO₂ flow and trapping behavior in a non-linear fashion. We then conduct similar experiments at different flow rates and demonstrate the persistence of heterogeneity effects even at high flow rates and capillary numbers in such vertical flows. These results help demarcate trapping behavior at near well bore and far field conditions. Together these experiments provide a unique opportunity to visualize complex multiphase flow dynamics in realistic geologic fabrics at the sub-meter scale, and can help bridge understanding between core scale experiments and reservoir scale observationsPetroleum and Geosystems Engineerin

SCALABLE CONTINUOUS-FLOW PROCESSES FOR MANUFACTURING PLASMONIC NANOMATERIALS

Master'sMASTER OF ENGINEERIN