This paper will examine an unusual intervention case history for a major UK North Sea operator, where a specialised coiled tubing (CT) conveyed mechanical cutter system was used to allow the recovery of stuck drill pipe.

Previous to the CT being mobilised to the offshore installation, a number of conventional drill pipe recovery techniques had been tried. However, all proved unsuccessful in freeing the stuck DP.

The decision was made to mobilise CT, dictated by both the need to free the High Strength S-135 DP and to confirm the degree of ID access for future intervention options. Ultimately a series of three mechanical cuts were made within the drill string. All cuts were at depths greater than 14,000 feet with 11.8 PPG OBM in the well. The particular challenges presented during this operation and the steps taken to provide a successful outcome will be explored.

Keywords:
drill string, drill pipe, mud motor, tool joint, anchor, flow rate, mechanical cutter, circulation sub, upstream oil & gas, coiled tubing operations
Subjects:
Drillstring Design, Drilling Operations, Drilling Equipment, Drilling Fluids and Materials, Completion Installation and Operations, Well Intervention, Coiled tubing operations
Copyright 2003, Society of Petroleum Engineers
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