LOW CLAY POLYCATIONIC DRILLING FLUID Russian patent published in 2023 - IPC C09K8/24 

FIELD: drilling fluids.

SUBSTANCE: invention relates to water-based inhibitory low-clay polycationic drilling fluids and can be used in drilling of argillaceous and productive deposits and workover of wells, where there are strict environmental requirements. The drilling fluid contains, by % of weight: clay powder 1.6-2.1; chalk 4.1-7.0; starch 0.8-2.1; cationic polymer polyepichlorohydrinadimethylamine in liquid form with an active substance concentration of 30 to 50 % 4.0-5.0; glycerine or propylene glycol 4.0-10.6; cationic polymer Silfok-2540C; the rest is water.

EFFECT: increased efficiency of drilling, as well as improved quality of repair of wells with low formation pressures.

2 cl, 1 tbl