An operator developing a geothermal field to generate and provide electricity in Indonesia focused on minimizing the potential for failure of planned wells throughout the expected field life. One of the main areas where this effort was directed was in the design and execution of primary cementing jobs during well construction. Wells drilled and completed earlier, in
Phase I, were found to suffer from various wellbore integrity issues. Inspection log data and cement job records from existing wells suggest the zonal isolation problems experienced on earlier wells may have been related to (1) structural failure of the conventional cement sheaths used and/or (2) ineffective cement slurry placement caused by poor hole cleaning of the drilling fluid and/or (3) ineffective removal of drill cuttings from the well during the hole cleaning.

Structural damage to the cement sheath can sometimes be in the form of debonding at the casing, formation interfaces, cement sheath cracking, and/or compressive shear. The damage can be  caused by stresses on the cement sheath brought on by well events such as cement hydration, well completion, and steam production. These events change the temperature and pressure under which the cement slurry is placed and cured. If these changes are severe, the cement sheath may be damaged, leading to zonal isolation failure.