Abstract: Well AT21X， which is an ultra-deep exploration well in Tahe Oilfield， adopts the ϕ 177.8 mm liner
cementing. The cementing operation is difficult owning to the deep depth， high temperature in the bottom hole，
high content of chloride ions and special well-structure. During the cementing， two slurries of different setting
times were used. In the slurries， 2% micro-silicon and 0.2% TAS153 were used to solve the problems caused by
the high temperature， high salt content， easy channeling and high water-loss when cementing an interval containing
salt formation. So the performances of cement slurries were improved as well as the cementing quality. Cementing
quality test result is that 100% cemented intervals are qualified， 90% good and excellent. The cementing technique
used provides a good example and some useful experiences， and can bring some guidance for the future cementing
operations concerning salt formation.

Key words: salt formation, liner cementing, cement slurry, cementing technology, pre-flushes