Transient method implemented under unsteady-state conditions for low and very low permeability measurements on cuttings

摘要

This paper reorts a complete description of a device, a numerical method and of a new experimental procedure that allows direct measurements of low and very low permeability on cuttings (small fragments of rock, down to 1-2 mm in diameter). The results show the determination of shale permeability even in the order of few nanodarcies. This technique is included in a complete package of 'standard' measurements on cuttings (sonic, rock strength, porosity) and in particular it extends the range of permeability measurements, technique already developed for reservoir cuttings and presented elsewhere. Thanks to this technique it is now possible to obtain, while drilling, a complete 'permeability log' of rock formation even for very low values.