Smart Cement Piezoresistivity Characterization with Sodium Metasilicate under Temperature and Curing Environments for Oil Well–Cementing

The smart cement behavior with 0.3% sodium metasilicate (SMS) at 80°C (176°F) under two different environments was investigated in this study. The smart cement was made using the class H oil well cement and 0.1% conductive filler to make it a bulk chemo-piezoresistive material with highly sensing property. The smart cement was cured in air and also submerged in water-saturated sand at 80°C up to 28 days. The smart cement initial resistivity (ρo) decreased from 0.97 to 0.87 Ω·m with 0.3% SMS, a 10% decrease. Similarly the minimum resistivity (ρmin) decreased from 0.81 to 0.72 Ω·m with 0.3% SMS, an 11% decrease, which is an indication of the chemo-resistivity of the smart cement. The resistivity changes were higher than the unit weight changes in the smart material. The resistivity of the smart material oven cured in saturated sand at 80°C was 55 to 75% less than the resistivity of the material cured at 80°C after curing for one, seven, and 28 days. The material resistivity with 0.3% SMS cured in ...