The FLO-CHEK® system is an externally catalyzed, soluble silicate system designed to control subsurface brine in production / injection wells in the area near the wellbore. Because of the method of reaction (externally catalyzed), the depth of matrix penetration is limited to the near-wellbore area. The temperature range is 40°F to 550°F (4°C to 288°C). This service can be used to handle problems, such as underground water movement behind casing, bottom-water production, and lost circulation. Drilling can continue once lost circulation is reduced with the FLO-CHEK system.
The FLO-CHEK system is often used ahead of a cement squeeze. In a two-stage operation, this material forms a very stiff, semisolid gel when it intermixes with a fluid containing multivalent cations, such as calcium or magnesium, and the reaction is instant. The FLO-CHEK system also reacts with formation brines (depending on the chemical makeup). However, the rate of reaction and the strength of the gel formed can be reduced considerably. If formation brines are used for this process, laboratory testing is required. The gel forms a bridge to block or divert the cement slurry. As the cement slurry intermixes with the FLOCHEK system, a very stiff gel that prevents cement from entering that zone forms. In some severe downhole conditions, it may be necessary to perform multiple stages. In freshwater or low brine concentration zones, pump a reactive brine (10% CaCl2) spearhead into the problem zone to react with the FLO-CHEK system.