Mississippi State University
Date of Degree
Dissertation - Open Access
Doctor of Philosophy (Ph.D)
James Worth Bagley College of Engineering
Dave C. Swalm School of Chemical Engineering
As the world pushes for ‘greener’ technologies and carbon neutrality, efforts have focused on creating novel ways to mitigate humankind’s carbon footprint. Carbon capture and storage (CCS) has become a prevalent technique that has proven to be an effective long-term method to safely relocate excess carbon dioxide (CO2) into subsurface formations. However, CCS is a newer technique which requires constant monitoring due to potential leakage pathways present in CO2 storage sites; therefore, a preventive approach to seal leakage pathways is recommended. This dissertation explores the potential of CO2-sensitive polyacrylamide (CO2-SPAM) as a novel sealing agent for enhanced oil recovery (EOR) and CCS applications. This manuscript explores the strength and weaknesses of various CO2-triggered chemicals and selects the appropriate fit for subsurface in-situ sealing. Relevant literature shows that CO2-SPAM can significantly reduce permeability in porous media. Additionally, organically cross-linked polyacrylamide-based gels, of which CO2-SPAM is one, are thermally stable, resistant to low pH levels, highly injectable, and widely used in various industrial processes. These characteristics make CO2-SPAM a suitable candidate for in-situ sealing. Further studies were performed to comprehend the chemical mechanism, rheological behavior, and injection effects of CO2-SPAM into subsurface formations. Firstly, past literature knowledge and organic chemistry principals were used to develop the complete chemical breakdown of CO2-SPAM gel’s synthesis. Secondly, the effect of salt and polyacrylamide (PAM) concentrations on gelation time, gel strength and viscosity were tested through qualitative (Sydansk gel strength coding system) and quantitative methods (rheometer measurement). The results showed that high salinities increase gelation time and decrease gel strength and viscosity, while high PAM concentrations do the opposite. Lastly, the effects on geomechanical stresses caused by CO2-SPAM injection into the subsurface are also addressed by using the image well method for pore pressure estimation, and frictional faulting theory. The final results determined that the injection of aqueous CO2-SPAM would induce seismicity in normal faulting zones dipping at a large array of angles in the plane of failure. These findings are significant as they determine the potential of induced seismicity in the area of CCS, which in this case was the Raton basin.
Quan Lopez, Iris Laihmen, "Experimental study on CO2-sensitive polyacrylamide as potential in-situ sealing agent for CO2 leakage pathways in geological storage sites" (2022). Theses and Dissertations. 5555.