Advanced Petrophysical and Facies Investigations of the Conasauga to Determine Impact on CO2 Storage and Site Selection
Amber Conner and Autumn Haagsma
Battelle
Abstract
The application of sedimentology and stratigraphy is important when evaluating potential reservoirs for CO2 storage. It is used to represent heterogeneity within a system and to predict how the formations change where there is limited data. The geologic concepts are used to better define storage systems, inform decision making, estimate CO2 storage volumes, and predict where CO2 will move. Advanced petrophysical analysis and facies characterization are critical tools in developing the geologic concepts.
Advanced petrophysics provides a detailed chemical and physical rock assessment, beyond basic petrophysical technologies, to better understand subsurface lithology, porosity, permeability, and fluid saturations. This helps guide the identification and classification of key facies that contribute to the system heterogeneity. These characteristics can then be correlated to basic petrophysical data to better identify and map reservoir attributes across a larger region.
The advanced petrophysical approach was applied to the Cambrian aged siliciclastics and carbonates of the Conasauga Group in Ohio. The Conasauga Group was previously characterized and classified as shaley carbonate due to high gamma ray signatures and carbonate facies. Multiple data types including wireline logs, both basic triple combo logs and advanced logs such as elemental spectroscopy, and whole and sidewall cores were integrated. Data was used to determine appropriate facies to represent the reservoir and non-reservoir intervals across Ohio. Facies characteristics were informed by elemental spectroscopy and core description data and then cross referenced with traditional log data including gamma ray, neutron porosity, photoelectric effect, and resistivity to define rock lithology.
The results show the importance of applying sedimentology and stratigraphy tools to a potential reservoir to identify prime storage intervals and locations. The Conasauga Group had the greatest potential for CO2 storage volumes in the central Ohio region, specifically in the identified feldspathic sandstone facies. Estimated storage volumes ranged from 17 to 42 Mt CO2/km3, making this formation a top storage target in Ohio.
BIO
Amber Conner
Amber Conner is a research geologist at Battelle with a focus on carbon capture, utilization, and storage projects. She leads formation characterization, site selection, CO2 monitoring, and risk mitigation assessments. She has a Bachelor of Science in geology from Central Michigan University and is currently pursuing a Masters in geology from the Ohio University.
Autumn Haagsma
Autumn Haagsma is a research geologist at Battelle with a focus on carbon capture, utilization, and storage projects. She leads formation characterization, site selection, static earth modeling, and risk assessments. She has a bachelors of science in physics and geology from Central Michigan University, a Masters of science in geophysics from the University of Minnesota, and currently pursuing a PhD in geology from Miami University.