DRILLING MUD Russian patent published in 1998 - IPC

FIELD: drilling of petroleum and gas wells. SUBSTANCE: in order to prepare highly inhibited drilling mud, three main inhibiting components ((CaCl₂,Ca(OH)₂,NaOH)) and foam suppressor in known formulation of chlorocalcium solution are substituted for one-component complex salt. The claimed drilling mud comprises clay, CMC and complex salt, the ratio of ingredients being as follows (wt %): 8-20 bentonite; 5-7 ; 1-2 CMC-600; 1.75-3.5 complex salt, and the water balance. In substituting three main inhabitants components for complex salt in known formulation of chlorocalcium solution equivalent CaCl₂ content (1-2 wt %) is retained and calcium cation concentration is maintained in filtrate at 3000-5000 ml/l. Inhibiting properties of the claimed solution is almost by twice as superior as identical properties of prior art chlorocalcium formulation of drilling mud. EFFECT: improved properties of drilling mud. 1 dwg, 2 tbl