Perforation cleaning tools

摘要

In accordance with illustrative embodiments of the present invention, a well perforation cleaning tool includes a fluidic oscillator that creates pressure pulsations which induce cyclical stresses in the walls of the perforations and causes damaged skins thereon to disintegrate in order to improve the productivity of the well. The output passages of one embodiment of the fluidic oscillator are connected to respective internal storage cavities and each cavity is communicated with the annulus by a pair of outlet passages. In other embodiments, relatively short length external cavities communicate with the output passages to provide means by which the pressure pulsations are conveyed to the well annulus. Cylindrical filter tubes having a plurality of sets of axially spaced slots are adjustably mounted at the upper and lower ends of the tool may, if desired, be used to provide resistances which substantially confine the pressure pulsations to the immediate vicinity of the tool body. Both tubing conveyed and coil tubing conveyed tools are disclosed.