THE APPLICATION OF CRITICAL PATH SCHEDULING TO ONSHORE DRILLING RIG MOVES

Abstract

One of a number of techniques to increase efficiency in the engineering industry which have appeared in the last few decades is Critical Path Scheduling. It is not much used in the petroleum industry, because its application is limited, but in many activities associated with drilling it can save time and money. Its use is illustrated by applying it to a typical rig move.

There is a time-cost relationship on any job. An unplanned job will take a time and have a cost which can be reduced by Critical Path Scheduling to a point where cost is minimal, because further reductions in time will involve overtime, airfreight, and other abnormal charges. These factors can be analysed and better judgements can be made.

The method used to apply Critical Path Scheduling is the Time Scale Arrow Diagram. It is a manual technique suitable for small to medium size jobs which has advantages in analysis and presentation over conventional methods employing computers. A rectangular, or parallel line diagram is used.

A rig move is a complex operation whose costs can be a significant part of those for a whole drilling operation. It is usual to rely on experienced personnel to arrange for the rig preparation, loading, trucking, and rigging up at the new location to be done in the most efficient way. Jobs vary depending on the arrangements between the operator and the contractor, distances, local conditions, and other such factors. The Critical Path Schedule enables an analysis to be made beforehand which will assist in obtaining maxiumum efficiency in the operation.