STRUCTURED FLUSH FLUID Russian patent published in 2023 - IPC C09K8/40 

FIELD: oil and gas well construction.

SUBSTANCE: flush fluids used in the process of casing wells to separate drilling and cement slurries, remove clay filter cake and ensure high-quality adhesion of cement stone to the casing string and rocks that form the walls of the well. The structured flush fluid contains a gelling agent, a stabilizer and a weighting agent. Lime is used as a gelling agent, a complex of water-soluble salts containing sodium chloride and/or potassium chloride, ammonium nitrate, sulfate and/or chloride of ns²np¹ elements in the form of boron and/or aluminum and/or gallium compounds is used as a stabilizer and sodium tetraborate at their specific ratio, and as a weighting agent - calcium carbonate, and/or barium sulfate, and/or iron oxide (III) at their specific ratio.

EFFECT: creation of a pseudo-plastic structured flush fluid that optimally meets the requirements of well casing under conditions of normal and abnormally high formation pressure (AHFP), which are drilled using polymer-clay loaded drilling mud.

2 cl, 1 tbl