METHOD OF TREATMENT OF DRILLING MUD WITH COMBINE REAGENT Russian patent published in 1999 - IPC

FIELD: drilling muds applicable in well drilling, particularly, preparation of high calcium drilling muds. SUBSTANCE: claimed method provides for use of cement- reagent supplying calcium ions, clay which prevents solidification of mixture and forms structure, viscosity reducer in form of spent sulfite-alcohol liquor or its derivatives, caustic soda and water, with the following amounts of components, wt.%: cement 10-25; clay 10-25; caustic soda 0.2-0.4; viscosity reducer 4-8; the balance water. Said composition is introduced into initial drilling mud in amount of 8-15% in 20-30 h for cement hydration after introduction of cement. EFFECT: higher efficiency. 4 cl, 1 tbl