Technique for insulating a wellbore with silicate foam

摘要

Disclosed herein is a method for thermally insulating a well. The well is insulated by boiling a solution containing silicate in contact with well tubing to form a coating of silicate on the tubing. A fluid substantially free of silicate also contacts the well tubing to buffer a lower portion of the tubing from the silicate solution. This substantially silicate-free fluid prevents silicate foam coating on the lower portion of the tubing and thus alleviates problems associated with having silicate foam coated thereon.