| 摘要 |
The secondary recovery of petroleum from subterranean formations by the waterflooding method is improved so that the said formations remain pervious, permit the fluid water to flow unimpeded and displace the residual oil from said formations by incorporating into the fluid water which is injected through an input well into said formations, a composition consisting essentially of a copolymer of methyl vinyl ether and maleic anhydride having a specific viscosity of from about 1.3 to 10 and from about 0.2 percent to about 1.5 percent by weight based on the total weight of the composition, of a mixture of inorganic salts consisting of alkali metal chloride, sodium bicarbonate and either calcium or magnesium chloride.
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