| 摘要 |
A method is provided for blocking high permeability channels in subterranean geological formations, using swelling clay. A slurry is prepare d by mixing swelling clay, such as bentonite, into an aqueous solution containing the salt of certain cations, which inhibit clay swelling. The cations K~, Ca2~ a nd Mg2~, among others, are inhibitive of clay swelling. The clay slurry is introduced into a geological formation, where it preferentialy enters channels of high permeability. There the slurry is contacted by NaCl brine solution present in natural or injected drive fluids, and the inhibitive cations bound to the clay particles are replaced by Na~ ions, which attract water molecules and promote clay swelling. The Na~ - clay swells to up to 10 times its original volume, causing the shiny to acquire a gel- like consistency. The clay gel so formed is capable of blocking the flow of water, and can resist pressure of up to 500 kPa per meter.
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