COMPOSITION FOR SELECTIVE LIMITATION OF WATER INFLUX IN PRODUCTION WELLS Russian patent published in 2024 - IPC C09K8/508 E21B33/138 E21B43/32 

FIELD: chemistry; mining.

SUBSTANCE: invention relates to compositions for limiting water influx in production wells during injection of the composition throughout the perforation interval, including in wells with an open hole and in wells with a horizontal hole. Composition contains 0.05-0.5 wt.% of a stabilizer – chromium acetate, 0.1-0.5 wt.% of a polymer reagent – an acrylic polymer, 0.01-0.5 wt.% of a surface property regulator – an amphoteric surfactant based on trimethylaminoacetic acid and water. Acrylic polymer used is anionic polyacrylamide with a degree of ionogenicity in range of 5-10 wt.% and molecular weight in range of 10-15 million amu. Amphoteric surfactant used is a derivative of trimethylaminoacetic acid with a C₁₁-C₁₆ radical in a mixture with ethylene glycol in ratio of 1:1÷2. Composition additionally contains 0.01-0.05 wt.% of a water-repellent regulator based on 3-aminopropyltriethoxysilane, as well as an acidity regulator – caustic soda.

EFFECT: providing selective action of the water-insulating composition due to sorption of components of the composition on the surface of the rock and changing its surface properties without forming a gel based on the polymer-crosslinker system, while maintaining its insulating properties for a long time and thereby increasing the duration of the water isolation effect with preservation of thermal stability under conditions of different formation temperatures (20-80 °C).

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