METHOD FOR WATER-PERMEABLE RESERVOIR ISOLATION Russian patent published in 2006 - IPC E21B43/32 

FIELD: oil production industry, particularly to isolate water-permeable formation intervals during well repair and plugging operations.

SUBSTANCE: method involves injecting aqueous solution of high-modulus sodium silicate and acid gel-generation agent; leaving thereof in well for time enough for gel forming and creating isolation screen having thickness determined as L=(P_d·K)/grad(P_s), where L is isolation screen thickness, m; P_d is rate of differential pressure drawdown in flooded productive reservoir area, MPa; K is load factor of isolation screen, K=1.2; grad(P_s) is gradient of initial pressure of reservoir water filtration through screen, wherein grad(P_s) is equal to 7.7-40.0 on experimental investigation data, MPa/m. The high-modulus sodium silicate is colloid sodium silicate, the acid gel-generation agent is liquid waste obtained during electrochemical metal coating application. Above components are mixed to form solution having pH value of 3-9.

EFFECT: increased efficiency due to increased strength of obtained isolation screen due to usage of solution having optimal gel forming time and determining of optimal isolation screen thickness, reduced time of isolation screen forming, extended range of gel forming materials along with improved ecology and possibility to utilize industrial waste.

1 ex, 2 tbl, 4 dwg