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doi:10.2204/iodp.proc.337.202.2017

Introduction

One of the scientific objectives of Integrated Ocean Drilling Program (IODP) Expedition 337 was to examine the feasibility of geological CO2 sequestration in deep offshore coal-formation repositories (Inagaki et al., 2012). Riser drilling during Expedition 337 penetrated a 2466 m deep sedimentary sequence at Site C0020 that included a series of coal-bearing layers at ~1.9–2.0 km below seafloor where microbial methanogenesis via CO2 reduction was observed (Inagaki et al., 2015). Hydrocarbon reservoirs (e.g., unmineable subsurface petroleum fields and coal beds) have been considered for use as geologic CO2 repositories. Likewise, recovery of coal bed methane associated with hydrocarbon reservoirs is possibly facilitated by CO2 injection and thus can contribute to decreasing the energy cost associated with such a venture (e.g., Gunter et al., 1997; White et al., 2003). To evaluate the potential of these applications, permeability data are important; however, permeability data from deeply buried offshore coal-bearing formations are rare. Here, we report relevant characteristics at Site C0020 by conducting flow-through permeability experiments on coal samples and grain-size analysis of a sand layer interbedded with the lignite coal.