HYDROGEL FLUSHING SYSTEM FOR DRILLING AND PRIMARY OPENING OF LOW-PERMEABILITY RESERVOIRS Russian patent published in 2025 - IPC C09K8/10 E21B21/00 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, namely to hydrogel drilling fluids for drilling oil and gas wells. System with density of 1,050-1,100 kg/m³ for drilling and primary exposure of low-permeability reservoirs includes a structure-forming agent, a filtrate yield reducer, a stabilizer, a hydrogel structure stabilizer and water. As a structure-forming agent, bischofite and sodium hydroxide are used, as a filtrate release agent – magnesium oxide, as a stabilizer – xanthan gum "Bioxan", and the hydrogel structure stabilizer is low-viscosity polyanionic cellulose "ПАЦ-Н", with the following ratio of components, wt.%: bischofite 6.2-19.6, sodium hydroxide NaOH 3.8-3.9, magnesium oxide MgO 1.6-0.8, xanthan gum "Bioxan" 0.2-0.1, low-viscosity polyanionic cellulose "ПАЦ-Н" 1.6, water – balance.

EFFECT: increasing inhibiting capacity of hydrogel drilling system, excluding contraction effect during cementing of casing strings of wells.

1 cl, 3 tbl