GROUTING MORTAR Russian patent published in 2001 - IPC

FIELD: well drilling. SUBSTANCE: invention relates to drilling oil and gas wells in formations with abnormally high pressures within temperature range between 60 and 140 C. Grouting mortar contains, wt %: grouting Portland cement 15.38-25.74, barite 22.06-46.15, hydraulic power station fly ashes 15.38-25.74, water - the balance. Portland cement is first mixed with fly ashes and resulting mixture is then introduced into vacuum hydraulic mixer simultaneously with 70-80 wt % of barite based on its projected amount and water fed under pressure. Thus obtained solution is stirred and hydraulically activated by recycling it through hydraulic mixer. After addition of the rest of barite, hydraulic activation of solution is repeated several times at pressure 8.0-12.0 MPa. EFFECT: increased heat resistance and strength of cement stone. 4 cl, 1 dwg, 2 tbl