SOLID PHASE-FREE DRILLING MUD (VARIANTS) Russian patent published in 2007 - IPC C09K8/08 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to drilling mud used for opening productive bed-collector. By the first variant drilling mud contains the following components, wt.-%: biopolymer xanthane "Saraksan-T" or "Saraksan", 0.2-0.6; chemically modified starch, 0.2-0.8; calcium nitrate, 14-50; ammonium nitrate, 2-7; froth breaker "Sofeksil 9056-20", 0.01-0.15, and water, the balance. By the second variant drilling mud contains the following components, wt.-%: biopolymer xanthane "Saraksan-T" or "Saraksan", 0.2-0.3; chemically modified starch, 0.1-0.3; calcium nitrate, 14-50; ammonium nitrate, 2-7; calcium chloride, 15-20; froth breaker "Sofeksil 9056-20", 0.01-0.15, and water, the balance. The density value of drilling mud is 1100-1600 kg/m³. Invention provides the creature of solid phase-free drilling mud and with retaining its rheological and filtrating indices for a long time and independently of the drilling mud density value.

EFFECT: improved and valuable properties of drilling mud.

2 cl, 2 tbl, 2 ex