DRILLING MUD Russian patent published in 2018 - IPC C09K8/08 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the field of drilling oil and gas wells, in particular to non-clay drilling fluids used for washing wells during drilling and opening of a productive formation with a vertical, oblique-directed or horizontal section of the shaft. Drilling mud comprises, wt%: Xanthan Petro biopolymer 0.3-0.45; modified starch 1.5-2.5; magnesium oxide 0.2-0.5; liquid water repellant - Petro Safe reagent 0.03-0.06; potassium alum 0.03-1.0; water - the balance. If necessary, the drilling mud may further contain at least one component from the group comprising a bactericide 0.01-0.05 wt%, marble chips 5-30 wt% or barite 5-40 wt%, sodium hydroxide 0.01-0.1 wt%, polyglycol 1-3 wt%, a lubricating additive 0.4-3 wt%.

EFFECT: technical result is lower interfacial tension at the boundary between the filtrate of the drilling mud and the formation fluid, reduced filtration of drilling mud into the reservoir with increased thermal stability of the mud.

1 cl, 1 tbl, 12 ex