BOREHOLE FLUIDS AND METHOD FOR USE THEREOF Russian patent published in 2019 - IPC C09K8/35 C09K8/34 C09K8/64 C09K8/80 E21B43/26 E21B43/267 

FIELD: soil or rock drilling.

SUBSTANCE: group of inventions relates to fluids for well operations. Reference fluid for producing well fluids comprises a mixture of synthetic aliphatic hydrocarbons obtained from a stream of Fischer-Tropsch synthesis products and containing more than 96 % aliphatic hydrocarbons with carbon atoms from C6 to C30, wherein the ratio of homologues with C9 and lower carbon atoms is less than about 0.35 wt. %, wherein said aliphatic hydrocarbons contain a greater amount of branched hydrocarbons than linear hydrocarbons, where the point of aliphatic hydrocarbon ignition is about 180 °F (82.22 °C) and more and wherein said fluid medium has a lubricating factor of 0.17 and less, and wherein the lubricating property is defined as the friction coefficient of the metal ring rotating in the base fluid at 60 rpm on the hard metal surface at 150 psi. Borehole fluid comprises said base fluid and at least one additive selected from a group consisting of emulsifiers, wetting agents, thickeners, weighting agents, water loss reducing agents, proppants and aerosol substances for forming gravel pack.

EFFECT: technical result is higher drilling speed, reduced twisting and axial loads on drill column, possibility of use in horizontal wells.

22 cl, 4 dwg, 4 tbl