Impact of Biogeomechanical Process on CO2 Sequestration in Hydrocarbon-Depleted Carbonate Reservoirs

Abstract

ABSTRACT: Carbon dioxide (CO2) sequestration in depleted oil and gas reservoirs is a key technology to mitigate anthropogenic CO2 emissions. In this study, we experimentally investigate the impact of biogeomechanical alteration on CO2 storage in a hydrocarbon-depleted carbonate reservoir using core samples from a deep carbonate formation in the Permian Basin United States. We first obtain the mechanical and microstructural properties of the carbonate samples using the scratch test method, and we treat the samples with a bacteria strain at distinct conditions. Then we expose the samples to CO2 in a supercritical state (ScCO2) for 21 days. We obtain the post-treatment properties of the microbially-treated samples and analyze the effect of the modified properties on long-term CO2 storage in the carbonate formation. Our results indicate that in hydrocarbon-depleted carbonate reservoirs, microbially-altered properties can enhance mechanical integrity and provide potential long-term security for stored CO2. 1 INTRODUCTION Carbon capture and storage (CCS) in geologic formations is a key technology for climate change to mitigate anthropogenic CO2 emission (Holloway, 1997; Lackner, 2003; Lebedev et al., 2017; Badghaish and Schwartz, 2021; Kolawole et al., 2021a; Ozotta et al., 2021a; Schwartz, 2022). Geologic media such as saline aquifers (Langenfeld et al., 2017a), limestone (Gozalpour et al., 2005; Lebedev et al., 2017), sandstone, basalt (Langenfeld et al., 2017b; Menefee and Ellis, 2021), and shale (Fatah et al., 2021a, 2021b; Kolawole et al., 2021a, 2021b, 2021c; Onwumelu et al., 2021; Ozotta et al., 2021a, 2021b, 2021c) are potential target CO2 storage reservoirs. Biogeomechanics is an emerging field of geomechanics that investigates geomechanical responses of microbial-rock interactions (Kolawole et al., 2021a, 2021b, 2021c). The microbe, Sporosarcina pasteurii (ATCC® 11859™) (Yoon et al., 2001), is observed to rapidly precipitate calcite in sand columns as the bacteria growth increases, for selective cementation and plugging of porous media (Stocks-Fischer et al., 1999; Kolawole et al., 2021a, 2021b).