DRILLING FLUID Russian patent published in 2023 - IPC C09K8/08 C09K8/38 

FIELD: drilling gas and oil wells.

SUBSTANCE: invention relates to the development of compositions of low-density drilling fluids for opening fractured intervals with abnormally low formation pressures. The drilling fluid comprises, wt.%: a filtration reducer and a drilling fluid stabilizer - a biopolymer based on xanthan gum Bioxan 0.25-0.50; hydrophobizing reagent based on tri(2-hydroxyethyl)amine and propane-1,2-diol - Polyphobe 0.8-1.0; a substance based on hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine to prevent degradation and decomposition of drilling fluid during long-term use - Polybaccid 0.05-0.10; foaming complex based on 1-hydroxyethylene diphosphonic acid - Polyphoscor 0.05-0.10; foaming composition based on alkyl C_10-16 N,N-dimethyl-N-benzylammonium chloride - Polypron-4 0.1-0.2; biodegradable bridging agent and filtration reducer for fresh and mineralized drilling fluids - peat-alkaline reagent Polygum 4.5-6.5; foam-forming organomineral complex of surfactants based on 2-hydroxy-1,2,3-propanetricarboxylic acid and diiron trisulfate - Polyreotsit 0.3-0.5; the rest is water.

EFFECT: reduction in well construction time, no catastrophic losses during drilling, and preservation of the reservoir properties.

1 cl, 1 tbl