Design No. Temperature (°C) Base NaCl Ambient Test 1 1 22.0 21.2 27.1 Test 2 1 22.9 21.8 27.8 Test 3 2 23.4 22.7 28.5 Test 4 2 23.7 23.2 28.9 Test 5 3 24.5 23.8 29.5 Test 6 3 24.6 24.4 30.0 The observed thermal homogeneity minimized experimental variability associated with thermal effects, ensuring that the differences recorded in initial viscosity and gel time are mainly related to chemical formulation and the relative dosage of activators and retarders. In the case of colloidal silica systems, moderate temperatures contributed to maintaining suspension stability prior to NaCl activation, preventing premature flocculation processes. 5.2 Initial Viscosity, Density, and Gel Time of the Systems The integrated results of Zahn viscosity, dynamic viscosity, density, and gel time (Tables 9 to 14) show that all evaluated systems exhibit very low initial viscosity, ranging approximately between 3.7 and 6.4 cP. This behavior confirms their high fluidity prior to the onset of gelation and their clear advantage over cementitious grouts, even ultrafine ones, for injection applications in narrow fractures and media with high pore connectivity. Table 9 – Viscosity (Zahn cup and dynamic), density, and gel time results for the acrylamide-based system Acrylamide-based system Test Design No. Zahn Viscosity (s) Dynamic Viscosity (cP) Density (kg/L) Gel Time (min) Test 1 1 32.64 3.68 1.03 45.47 Test 2 1 - - - 64.10 Test 3 2 - - - 86.11 Test 4 2 - - - 84.27 Table 10 – Viscosity (Zahn cup and dynamic), density, and gel time results for acrylate system A Acrylate system A Test Design No. Zahn Viscosity (s) Dynamic Viscosity (cP) Density (kg/L) Gel Time (min) Test 1 1 33.09 4.13 1.06 32.00 Test 2 1 33.12 4.16 1.06 41.17 Test 3 2 - - - 39.10 Test 4 2 - - - 41.12 Table 11 – Viscosity (Zahn cup and dynamic), density, and gel time results for acrylate system B Acrylate system B
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