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Drilling with casing is among the top ten promising technologies to reduce well construction costs. It consists in using directly the casing as the drill string. Such a technique does not only reduces tripping time, but also decreases the risk of downhole problems and provides a safer working environment, all leading to an overall well construction cost cut by 30%.However casing connections were initially designed to withstand static tensile loads and have poor fatigue resistance properties. Intermediate solution was to use metal to metal seal buttress threads, which enable to drill down to 3,000 m with some success. The performances of these connections using thermo-chemical surface treatments have been investigated using a fit for purpose workbench, and promising results such as a 32% increase in admissible fatigue load, as well as an elastic limit of threads increase in 50%, have been observed. A complete fracture analysis was performed using Scanning Electron Microscopy (SEM).
About the author
Emil Leporcher accomplished his double Master's program in both Ecole Centrale in Lyon and in TsingHua University in Beijing in 2008. Then he joined the oil&gas industry, where he pioneered in optimizing operating efficiency, thanks to the permanent implementation of new technologies, to extend the life time of existing producing wells.
