DRILLING FLUID FOR INJECTION AND REPAIR OF WELLS Russian patent published in 2003 - IPC

FIELD: oil and gas production. SUBSTANCE: invention relates to drilling fluids for injection and repair of wells as well as to washing fluids that can be used for killing wells when mounting bottom screened pipes and performing underground and total repair of wells. Drilling fluid contains, wt %: chalk 15-30, mineral salt 0.2-1.0, carboxymethylcellulose 0.5-1.0, alkali 0.05- 0.1, surfactant 0.01-0,03, condensed sulfite-alcohol distillery dregs, foam suppressor (flotation reagent) 2.0-5.0, and water - the rest. Fluid can further contain 5-7% of mud powder. EFFECT: increased stability of fluid, reduced clogging of productive formation, and enhanced efficiency of subsequent salt-acid treatment. 2 cl, 3 tbl, 2 ex