CLAY-FREE DRILLING MUD Russian patent published in 2001 - IPC

FIELD: drilling fluids. SUBSTANCE: clay-free drilling mud for drilling boreholes with abnormally high formation pressures, including water and acrylic ingredient, contains mineralized water (in particular, formation water), 0.1-0.3% polyacrylamide as acrylic ingredient, and, additionally, 0.2- 0.25% long-chain anionic cellulose polymer, and 1.0-1.5% sodium silicate. EFFECT: preserved initial collecting properties of producing formation and ensured high flocculating properties for removal of drilling cuttings when exposing productive strata with high formation pressures. 2 cl, 1 tbl