The following guidelines should be considered to to avoid hole related problems ....
1. In 12 1/4" hole, do not use 9 1/2" drill collars. Reduce the number of drill collars by replacing them with HWDP if possible.
2. When reaming long intervals, use the minimum practical number of drill collars, (see (1) above concerning HWDP). Also, avoid using stabilisers, unless hole indications dictate otherwise, in which case only the minimum amount should be used.
3. In case of hole problems use nozzles no smaller than 16/32" (13 mm).
4. On check trips prior to running casing, or in between logs, run less drill collars if possible, but leave the position of the remaining stabilisers unchanged.