| 摘要 |
The invention provides a method for the enhanced recovery of oil from an oil-bearing stratum having a zone of high fluid permeability through plugging of this zone by introducing into the stratum a gelable solution which, in the case of use under moderately high operating temperatures in the stratum, comprises a polyphenolic lignin extract, a formaldehyde source and sufficient alkaline material to give a solution having a pH of at least 9.0 and which, in the case of higher operating temperatures, comprises a lignosulfonate and a source of formaldehyde or tannin in aqueous solution.
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