A Silicate Based Process for Plugging the Near Well Bore Formation

Abstract : A method for treating the surrounding of a well using a reactive suspension is studied, using silicate based solutions. They present the following key qualities: high performance, long term chemical stability, good injectivity, little environmental impact. We present an experimental investigation of the precipitation of commercial low-cost potassium silicate solutions, using a weak acid to lower the pH. Experiments were performed between 20°C and 60°C, by adding a non-hazardous acidic compound to the silica based solution. Bulk gelation times were estimated between a few minutes to 4 days. A coreflood injection experiment was then performed on an analog sandstone sample, representative of CO 2 formation, by using an optimum mixture with viscosity close to water. After a few days, a breakthrough experiment was performed by increasing gradually the differential pressure across the sample. Preliminary results indicate a very large strength of the order of 600 bar/m.