METHOD FOR COLMATAGE OF WELL PERMEABLE FORMATION Russian patent published in 1995 - IPC

FIELD: oil producing industry. SUBSTANCE: colmatage of formation at definite distances and preset intervals is effected by periodic injection in formation of fringes consisting of two sedimentation process solutions separated by spacer fluid which acts also as displacing fluid. Distance of interval of colmatage zone in formation in region of mixing of sedimentation process solutions is determined under the conditions of equality of width of fringes at definite distance of their supply to formation with length of filtration dispersion at same distance. Fringe width is calculated by the formula , where λ is parameter of hydrodispersion, m; l_f is boundary of zone of piston displacement, m; a is factor considering flow structure. Sedimentation solutions are used in form of aqueous solutions of sodium bisulfate and calcium chloride. Displacing fluid is used in form of formation water and surfactant compatible with formation water. EFFECT: speeded up colmatage of permeable formation in preset length of colmatage interval. 3 cl, 1 dwg