| 摘要 |
Drilling of wells in subfreezing environments is conducted by using a fluid which contains a major amount of an aqueous medium such as sea water or fresh water, a heteropolysaccharide produced by the action of bacteria of the genus Xanthomonas, an oxygenated hydrocarbon dispersant which may be a polyhydric alcohol such as ethylene glycol and, optionally, an alkaline medium to provide a desired pH, the polyhydric alcohol aiding in the dispersion of the heteropolysaccharide in the aqueous medium and acting as a freezing point depressant of the drilling fluid.
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