POLYCATIONIC DRILLING FLUID FOR DRILLING SALT DEPOSITS Russian patent published in 2023 - IPC C09K8/24 

FIELD: water-based drilling fluids.

SUBSTANCE: invention can be used when drilling unstable clayey rocks and opening productive formations. The drilling fluid contains, wt.%: clay powder 1.4-2.7; cationic polymer Silfok-2540S 0.8-1.6; high molecular weight thickening xanthan biopolymer Glamin 0.14-0.27; modified starch Reamil 1.4-2.0; sodium chloride 21-25; flotation reagent oxal T-92 0.7-2.1; water - the rest; barite 430-1700 kg/m³ over 100 wt.%. Barite is used in an amount of 430-1130 kg/m³ to obtain a drilling fluid density of 1.50-2.00 g/cm³, in an amount from more than 1130 to 1700 kg/m³ to obtain a drilling fluid density of more than 2.00 to 2.40 g/cm³.

EFFECT: production of a salt-saturated, high-density drilling fluid with improved structural and rheological properties, resistant to aggressive factors.

4 cl, 1 tbl