Method of treating a high temperature formation to permit the use therein of temperature sensitive hydrophilic, viscosity increasing polymers

Abstract From the Canadian patent

Polymer flooding is an effective means of increasing the sweep efficiency of a displacement process for recovering petroleum from a subterranean petroleum, containing formation; however most polymers suitable for, use in flooding operations hydrolyze or otherwise decompose at temperatures above about 150°F to 200°F and the tem-, perature of many subterranean petroleum-containing formations is in excess of 150°F-200°F. Polymers may be employed in tertiary recovery in formations whose temperatures are greater than the temperature stability limit of the polymer if the formation temperature is first reduced by introducing an aqueous fluid such as water at a temperature substantially below the …