METHOD OF STRENGTHENING WELL WALL IN DRILLING Russian patent published in 2000 - IPC

FIELD: oil-and-gas producing industry. SUBSTANCE: method relates to methods of preservation of reservoir properties of producing formation during their primary drilling. Method includes treatment of well wall with jet of drilling mud flowing out of side nozzle of colmatage sub and containing finely dispersed fraction in the form of finely dispersed hydrophobic material with particles sizing from 0.1 to 100 mcm. Said drilling mud is supplied to well wall surface layer at velocity of 70-80 m/s with its concentration of 0.02-0.03 wt.% during drilling in. Finely dispersed hydrophobic material may be used in the form of swollen graphite or white black, or aerosil, or perlite. Prior to supplying of finely dispersed hydrophobic material to drilling mud, it is mixed with oil and surfactant in the following ratio of components, wt.%: finely dispersed hydrophobic material, 0.02-0.03; oil, 10; surfactant, 0.01; drilling mud, the balance. EFFECT: strengthening of well wall in drilling due to increased efficiency of isolation of permeable formations at the moment of their primary drilling in. 3 cl, 1 dwg, 1 tbl