ACIDIC FLUSHING FLUID FOR POLYCATIONIC DRILLING FLUIDS Russian patent published in 2025 - IPC C09K8/40 

FIELD: mining; chemistry.

SUBSTANCE: invention relates to oil and gas industry in well construction, in particular, to flushing fluids used for separation of grouting and drilling fluids, destruction and removal of filter cake of polycationic drilling fluid from well wall and film of polycationic drilling fluid from casing string. Acidic flushing fluid for polycationic drilling fluids contains the following, wt.%: citric acid 3.00-10.00; oxalic acid 1.30-2.20; alkali metal chloride 1.50-3.00; triethanolamine 0.30-0.45; water 84.35-93.90. Alkali metal chloride used is sodium chloride or potassium chloride or a mixture thereof.

EFFECT: improving quality of well cementing due to enlarging the area of contact of cement stone with the well wall, complete destruction and removal of filtration crust of polycationic drilling fluid from the well wall and removal of polycationic drilling fluid film from the casing string.

1 cl, 1 tbl, 8 ex