Method for monitoring cement using polymer-based capsules

A method for monitoring structural integrity of a cemented wellbore, the method comprising the steps of:

• mixing an aramide capsule, a cement, and a water to form a cement slurry, where the aramide capsule is formed by the steps of:
• mixing a continuous solvent and a surfactant to produce a continuous phase;
• mixing a dispersed solvent and a dispersed monomer to produce a dispersed phase, where the dispersed solvent and the continuous solvent are immiscible;
• mixing the continuous phase and the dispersed phase to form a mixture having an emulsion such that the dispersed phase is dispersed as droplets in the continuous phase, where an interface defines the droplets of the dispersed phase dispersed in the continuous phase;
• adding a crosslinker to the mixture;
• allowing an aramide polymer to form on the interface of the droplets, such that the aramide polymer forms a semi-permeable membrane around a core, where the core contains the dispersed phase, such that the semi-permeable membrane around the core forms the aramide capsule;
• allowing the aramide capsule to settle from the mixture;
• separating the aramide capsule from the mixture using a separation method;
• and
• drying the aramide capsule such that the core is hollow, where the aramide capsule exists as a free flowing powder;
• injecting the cement slurry into a drilled wellbore;
• allowing the cement slurry to set to form the cemented wellbore, where the aramide capsule is embedded in the cemented wellbore;
• and
• detecting imperfections of the cemented wellbore by measuring electrical conductivity of the cemented wellbore.