Geomechanical Effects of CO2 Saturated Brine on Reservoir and Seal Rocks

Reducing the amount of CO2 in our atmosphere is a critical goal that we all recognize as essential. Addressing the issue requires careful consideration of different reservoirs that can be utilized for sequestration purposes, including coal seams, enhanced oil recovery, depleted hydrocarbon reservoirs, and deep saline aquifers. Currently, there is a growing interest in deep saline aquifers due to their vast storage potential and the absence of previous penetrations that may lead to CO2 leakage. Nevertheless, the long-term consequences of CO2 injection on the seal and reservoir rocks remain uncertain, specifically with respect to water pH levels. Research suggests that significant CO2 equilibration with lowsalinity waters could result in the pH of brine reaching 3.5 pH, exhibiting a deleterious effect on calcite, potassium feldspars and high surface area clay minerals. Furthermore, multiple minerals could be adversely impacted by prolonged exposure to CO2. Fortunately, software packages such as PHREEQC and OLI permit static and dynamic geochemical models, while established core analysis methods can assess variations in strength, texture, and visual appearance of both seal and injection reservoir rocks. As such, we will delve into these conventional core analysis methods to evaluate potential changes in rocks with very low permeability and porosity, as well as high-quality target injection reservoirs. All content contained within this webinar is copyrighted by Kory Holmes and its use and/or reproduction outside the portal requires express permission from Kory Holmes.

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