Master's Thesis Defense - Cody Prather
- Monday, April 20, 2015 at 12:00pm
- Roberts Hall, Room 121 - view map
Cody Prather M.S. Thesis Defense : NMR studies of capillary trapping in geologic CO2 sequestration and immiscible two-phase flow in porous media
Significant increases in atmospheric concentrations of CO2 has led to the need for viable means for reducing emissions of this greenhouse gas. Carbon capture and sequestration (CCS) is the process by which CO2 is captured and injected into deep underground saline aquifers, or in depleted oil and gas fields, for secure storage. Capillary trapping is a prominent mechanism for initially trapping CO2 in pore structures of these deep underground rock formations. It is therefore important to characterize and understand the residual saturation and distribution of CO2 within the pore structure.
Nuclear magnetic resonance (NMR) techniques are used to noninvasively monitor the drainage/imbibition of air, CO2, and scCO2 with DI H2O in a Berea sandstone rock core under reservoir conditions. Because of the thermophysical properties of scCO2, analogue fluids used for simplification, such as air, may not be representative of the actual processes under geologic conditions. Thus, this study will compare the capillary trapping of air with that of supercritical CO2, as well as subcritical CO2 to supercritical CO2. Furthermore, the distribution of the H2O in the pores is monitored via NMR relaxometry in order to provide some insight into which pores may trap the nonwetting phase and to track the drainage/imbibition through the pore structure.
Also, a brief NMR study of immiscible two-phase flow in porous media will be discussed. Because of its unpredictable nature and existence in many industries, it would prove valuable to determine flow patterns and understand the fluid mechanisms from a capillary number/pressure gradient relationship. Therefore, NMR techniques are utilized to provide snapshots of the water saturation distribution within a bead pack and help elucidate flow patterns during the steady state regime.
- Department of Mechanical & Industrial Engineering