Polymer-cement composites with adhesion and re-adhesion (healing) to casing capability for geothermal wellbore applications

Abstract Deterioration of cement/casing adhesion in wellbore scenarios can result in unwanted and potentially harmful leakage with the potential of serious repair costs. In this work, the authors explore the use of self-healing polymers added to conventional wellbore cements as a way to bring about self-healing and readhering (to casing) properties to the composite. Self-healing capability was demonstrated by permeability analysis showing that polymer-cement composites reduce flow by 50–70% at cement bulk and at the cement/steel interface. Use of atomistic simulations imply that these polymers have good wetting properties on the steel surfaces. Interactions between steel/polymer and cement/polymer are complementary, resulting in a wider range of bonding patterns. Cracks seem to expose under-coordinated sites that result in more bonding interactions, which agrees well with the permeability measurements showing high degree of healed cracks and cement-steel interfacial gaps together with an overall increased in structural integrity of these advanced polymer-cement composite materials.