METHOD OF PRODUCING REAGENT FOR CLAY DRILLING FLUIDS Russian patent published in 2024 - IPC C09K8/35 

FIELD: drilling soil or rocks; chemistry.

SUBSTANCE: invention relates to drilling of oil and gas wells, in particular to reagents for chemical treatment of drilling fluids in various mining and geological conditions. Method involves modifying 50% aqueous solution of sodium lignosulphonate followed by drying. Polycondensation of acrylamide and citric acid with formalin in the presence of hydroquinone at temperature of 90°C for 3 hours at molar ratio of acrylamide : citric acid : formalin : hydroquinone 2:2:4:0.02. Further, sodium lignosulphonate is modified in two steps, where, first, into the obtained mass of the synthesized modifying agent in portions, with constant stirring, aqueous solution of technical sodium lignosulphonate is added at a ratio by weight of dry substances of modifying agent to technical sodium lignosulphonate of 48.9 wt.% :  49.7 wt.% at process temperature 80±5°C and duration of 2 hours. Then, at the second stage of modification, nitrilotrimethylphosphonic acid is added to the reaction mass with constant stirring, and the process is carried out at temperature of 60±5°C for 1 hour, wherein initial components are used at the following ratio, wt.%: 50% aqueous solution of sodium lignosulphonate – 49.7, synthesized modifier – 48.9, and nitrilotrimethylphosphonic acid – 1.4.

EFFECT: obtaining modified lignosulphonate reagent for clay drilling muds, having effective reduction of relative viscosity indices and resistance to temperature aggression.

1 cl, 2 tbl, 15 ex