BLOCKING BIOPOLYMER COMPOSITION Russian patent published in 2021 - IPC C09K8/35 C09K8/44 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, in particular to water-based drilling fluids used during well completion, and to process fluids used during underground well repairs in fields with a fractured-pore type of reservoir under conditions of abnormally low reservoir pressures and high gas factor. The technical result of the invention is to ensure the regulation of gel time, which allows composition to be delivered directly to the bottom of the well, and thermal stability of the composition with possible regulation of composition rheological properties, preserving filtration and capacitance characteristics of the bottomhole formation zone. The blocking biopolymer composition contains a polysaccharide gel-forming agent, which uses xanthan gum, cross linker and water. The composition additionally contains a crosslinking regulator "2-Mercaptoethanol", and chromium acetate is used as a crosslayer with the following ratio of components, mass. %: xanthan gum from 0.5 to 1.2, chromium acetate from 0.15 to 0.2, crosslinking regulator "2-Mercaptoethanol" from 0.06 to 0.13, water - the rest.

EFFECT: invention ensures regulation of gel time, which allows composition to be delivered directly to well bottom, and composition thermal stability with possible regulation of composition rheological properties, preserving filtration and capacitance characteristics of the bottomhole formation zone.

1 cl, 2 tbl