Wells are subjected to substantial stresses from pressure and well testing, injection and stimulation treatments, thermal effects, production cycling, and changes in the surrounding formation over years, even decades. The casing string will expand or contract with these changes and stress the casing, the cement sheath and the formation. If these stresses exceed the capacity of the cement sheath, the annular seal can succumb to these forces, compromising zonal isolation and reducing the economics of the well through loss of hydrocarbon production, production of unwanted fluids and/or costly remediation.
To help avoid remedial cementing or plug and abandonment of the wellbore, Halliburton has scientifically investigated the potential damage to the cement sheath and offers a class of expanding, self-healing cements. The new system works on the premise that the migrating fluids react with the cement, causing it to expand and automatically seal the flow path, helping prevent further fluid migration. The latest of these systems are LifeCem™ and LifeSeal™ cements. The reactive components of these cement systems will remain dormant in the annulus, automatically responding in the event of encountering unwanted hydrocarbons and re-establishing the annular seal.