CARBON-BASED DRILLING FLUID WITH MULTI-WALLED CARBON NANOTUBES (MWCNT) Russian patent published in 2024 - IPC C09K8/36 B82Y99/00 

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry, namely to construction of production wells in difficult geological conditions. Hydrocarbon-based drilling mud, which is an inverse emulsion, contains a dispersion medium – low-viscosity base oil for hydrocarbon-based solutions REBASE grade “РС-230”, disperse medium – aqueous calcium chloride brine CaCl₂ 35 vol.%, nonionic emulsifier REBASE of “РС-510” grade based on esters of higher unsaturated fatty acids, structure-forming agent – organobentonite CPRHS, water-repellent agent ABR is a hydrocarbon solution of condensation products of fatty acids and amines, multi-walled carbon nanotubes MWCNT Taunit-MD, inner diameter of which is 5-15 nm, and outer diameter is 8-30 nm, specific surface area is more than 270 m², length exceeds 5 mcm, number of carbon layers is 30-40 pieces, at the following ratio of components, wt.%: said brine 39.9-40.4; emulsifier REBASE “PC-510” 2.16; organobentonite CP-RHS 1.40; water repellent ABR 0.375; MWCNT Taunit-MD 0.1-0.5; said oil is the rest. MWCNTs Taunit-MD are added to said brine and mixed with a high-speed mixer at 20,000 rpm. Obtained suspension is treated with an ultrasonic disperser for 60 minutes at power of 40 W. In said oil CP-RHS organobentonite, emulsifier REBASE “PC-510”, water repellent ABR are added, then said oil and brine with MWCNT-MD are connected during continuous mixing on a high-speed mixer at 20,000 rpm.

EFFECT: maintaining stability of well walls during well construction in areas of abnormally high formation temperatures in weakly consolidated rocks, reduction of water consumption and drilling wastes with simultaneous reduction of reagent consumption.

1 cl, 4 dwg, 2 tbl