Characterization of the Smart Oilwell Cement Modified with Metakaolin
For a successful cementing operation, it is critical to determine the flow of cement slurry between the casing and formation, the setting of cement in place and performance of the cement after hardening. At present there is no technology available to monitor cementing operations in real time from the time of placement to the end of the borehole service life.
In this study well cement was modified using carbon fibers and other additives to give it better sensing properties, also known as smart cement, so that its behavior can be monitored during the cementing operation and its life time. The electrical resistivity was identified as the sensing property of the smart cement slurry and hardened cement. In this study up to 10% Metakaolin was used. Metakaolin increased the initial resistivity of cement by 25%, the piezoresistive behavior of the cement increased by about 60% and the cement compressive strength improved by about 20%. Contamination can be detected by means of the initial resistivity and its negative effect on the compressive strength and sensing properties was reduced by means of the addition of Metakaolin.