Long-Term Evaluation of Low-Density Cement, Based on Hollow Glass Microspheres, Aids in Providing Effective Zonal Isolation in HP/HT Wells: Laboratory Studies and Field Applications

摘要

Cementing a string in one stage is a challenging task, especially in the presence of weak formations. Cement slurry losses during placement is highly possible if the equivalent circulating density (ECD) exceeds 11 lb/gal during placement. A conventional method to overcome this challenge is to use multi-stage cementing by setting the stage tool above the loss circulation zone. However, field data indicate that the tool can fail, thus causing serious delay and economic loss. A second method for zonal isolation is to use low density cement.