Auto Release Drill Collars

Abstract The drilling industry is currently exploring various ways of reducing costs through multitude of initiatives. One of the major areas where there is potential for cost reduction is downtime due to drill string failures. Differentially stuck pipe (DSP) occurrences are common everywhere, and account for a significant amount of non-productive time and ends up as one of the major causes of increased well costs. In some areas, events related to differentially stuck pipe can be responsible for as much as 40% of the total well cost. The risks if DSP increases when drilling depleted reservoirs, and, due to the low profitability of such projects, any undesired event could hurt the economics of these developments. Even though this is an old problem, with new drilling technologies, especially related to the use of drill collars, which is one of the main component of down hole assembly which in 60% of cases gets stuck, therefore there is a need to redesign the drill collars which can be able to drill ahead even in case of depleted reservoirs without getting differential stuck. In this paper, a new solution to DSP has been proposed. In addition, field cases are presented describing what the losses due to DSP are; the best option to reduce the risks of DSP is suggested. A simple drill collar is designed in such a way that the surface area of the drill collar is not is contact with the depleted reservoir or mud cake which is built up at the side of the wall. The drill collar is designed in such a way that it does not get differential stuck, can drill ahead and easily retrieved even in depleted reservoirs or in case of thick cake built at the side of the well bore wall. This technique will eliminate many of the conventional stuck pipe problems allowing for easier and fasten drilling, thus saving rig time and ultimately economics of the entire operation at a fraction of increased cost in the new drill collar.