A number of issues can arise when drilling through Zechstein formation
s that have a bearing on the health and safety of personnel, as well a
s on the time to complete operations and final well costs. Operational
problems present some intrinsic hazard or safety risk. Additionally,
the procedures applied to alleviate these problems also present a safe
ty risk, as they are usually nonroutine and unfamiliar, thus increasin
g the likelihood of errors. In this paper, the operational issues, the
ir causative mechanisms, and alleviation procedures are introduced and
categorized. Decision analysis is applied to each of the operational
issues, for both the well planning stage and for the drillsite, which
relates the well responses to the causative mechanism and, therefore,
to the selection of the most appropriate alleviation procedure.