METHOD FOR DRILLING AND PRIMARY OPENING OF PRODUCTIVE LAYERS Russian patent published in 2021 - IPC E21B21/00 C09K8/10 

FIELD: mining industry.

SUBSTANCE: invention relates to the field of drilling wells. The method for drilling and primary opening of productive formations in difficult mining and geological conditions includes the preparation of a water-based drilling mud containing, kg/m³: caustic and/or soda ash 0.3-1.3; sodium chloride 100.0-250.0; defoamer 0.1-0.5; bischofite 80.0-100.0; starch reagent 8.0-10.0 or high-viscosity carboxymethylcellulose 3.0-8.0; xanthan biopolymer 1.0-3.0; lubricant additive 0.5-2.0; drilling from under the conductor using the specified drilling mud, replacing part of the specified drilling mud 10-30 m before the cover of the productive formation with a portion of 60-80 m³ of the second prepared water-based drilling mud containing, kg/m³: caustic and/or soda ash 0.3-1.3; sodium chloride 220.0-250.0; defoamer 0.1-0.5; bischofite 100.0-120.0; starch reagent 12.0-14.0 or high-viscosity carboxymethylcellulose 3.0-8.0; xanthan biopolymer 2.0-4.0; colmatant calcium carbonate 30.0-65.0; lubricant additive 3.0-6.0, opening of the productive formation using the second drilling mud.

EFFECT: increased productivity and quality of well construction in difficult mining and geological conditions due to the complex effect of the composition of the drilling mud and the appropriate application technology.

1 cl, 6 tbl, 1 ex