エタノールベントナイト混合液の多孔質媒体内への圧入と孔隙の閉塞に関する実験

抄録

Storage of carbon dioxide in deep geological formations is considered to be an effective measure for mitigation of global warming because it uses many of the same technologies that have been developed in upstream oil and gas industry. However, in the implementation of carbon dioxide geological storage, development of more reliable well plugging method is one of the critical issues for long-term reduction of potential risk of carbon dioxide leakage through the abandoned injection wells.
We carried out a preliminary study on prevention of carbon dioxide leakage by use of ethanol-bentonite slurry injected into the near-wellbore formation during well abandonment procedure to reduce its permeability. We conducted a set of horizontal one-dimensional flow experiments using a glass-bead packed bed in a transparent acrylic cylindrical holder for four types of ethanol-bentonite slurry, which respectively had a different kind of bentonite clay suspended. We confirmed by visual observation that ethanol-bentonite slurry might be injected with filtration depending on the type of bentonite clay. A certain degree of pore plugging by hydration swelling of bentonite clay with time elapsed after injection was estimated to occur from the result of pressure drop measurement.