Shell Expro was confronted with an unacceptable high cost attributable to drillstring failure in 1991. One specific drilling unit experienced 5 failures within a two month period. The cost of these failures alone was estimated to be more than £2 MM.
A Drillstring Failure Prevention Quality Improvement Project (QIP) was instigated with the objective of reducing drillstring failure frequency, and hence Non Productive Time (NPT) costs, by at least 50% in 2 years. This goal has been achieved by carrying out detailed autopsies of failed components to determine 'root cause' of failures.
Analysis of the root causes and symptoms resulted in a series of improvement strategies which have been implemented to successfully reduce drillstring failure. NPT costs associated with drillstring failure have been dramatically reduced from £6.5 MM in 1992, to less than £1.0 MM in 1994.