METHOD OF CHEMICAL TREATMENT OF CLAY DRILLING MUDS Russian patent published in 1999 - IPC

FIELD: drilling of oil and gas wells. SUBSTANCE: method comprises adding preliminarily prepared peat-lignosulfonate agent to clay suspension-based drilling mud in amount of 2-7 wt % (0.1-0.3 % by dry matter). Agent is prepared under stationary conditions or prior to treating drilling mud using stirring devices. Agent retains technological activity for 24 months. Peat-lignosulfonate agent comprises the following ingredients, wt %: peat, 4.5-5.5; caustic soda, 0.0325-0.40; industrial ligno-sulfonates, 0.75-1.25; sodium and potassium bichromates; and water, the balance. Agent is essentially brown homogeneous paste-like compound which trickles down by gravity or pumped through. Method is ecologically safe. EFFECT: lower catching dangerous properties of drilling mud due to lower friction coefficient and higher inhibiting properties; efficiency of chemical treatment and reduced cost and labor consumption. 2 cl, 2 ex, 2 tbl