Non-Productive Time (NPT) Analysis, New Opportunity in Drilling Operation Management

As time goes by, increase in world energy demand forces oil and gas companies to drill deeper in order to produce more oil and gas for satisfying human needs. This requires drilling deeper layers with variable characteristics and consequently facing with more drilling problems. Much time should be spent on dealing with drilling problems as well become deeper. Non-Productive Time (NPT) is defined as time which drilling operation is ceased or penetration rate is very low. Time spent on fishing, pipe stuck, weather, tool transportation, lost circulation and tripping in/out can be counted as NPT. In project management point of view, drilling operation should be always at least on schedule and on budget. Occurrence of drilling problems and some technical and untechnical waitings push drilling operation behind the schedule. This means spending much time on a project which financially is not favoured for drilling contractors. Total drilling time can be broken down to conventional drilling time, reducible and irreducible nonproductive time. Recognizing reducible NPTs in order to diminishing them through an integrated management plan for future works is of great demand in drilling industry. In this paper, drilling time for over 10 wells in Middle East is analysed which showed that wellbore stability issues and trip time are major causes of NPT especially in drilling non-vertical wells. This integrated drilling management study resulted in a modified well proposal based on reducing NPT for future drilling operation in the area under study.