| CPC B24C 7/00 (2013.01) [B24C 1/045 (2013.01); B24C 5/04 (2013.01); E21B 43/11 (2013.01)] | 18 Claims |

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1. A fluid-driven dual-mode tool, operating as a component in a drill string and generally cylindrically shaped, wherein interrupting and then reinstating the inflow of pressurized fluid into an upper end of the tool from the drill string allows starting and stopping forcibly ejected fluid from the tool for abrading or perforating a target, comprising:
an upper sub accessing the interior of the drill string above the tool and a lower sub accessing the interior of the drill string and a bottom hole assembly below the tool;
a first set of flow paths connecting with a central bore in the tool and exiting on the sides of the tool, which provide abrasive pressurized fluid at the exits when open;
a second set of flow paths connecting with the central bore and exiting into the lower sub;
a J-slot piston with an outer surface having a ratchet path etched around its circumference, said ratchet path having alternating peaks and valleys, and said ratchet path is engaged with one or more guiding pins fixed on an inner wall of the tool, said J-slot piston further including at least one pair of flow channels extending axially through the J-slot piston and wherein said flow channels are alternately aligned with either the first set of flow paths or the second set of flow paths if the pins reside between peaks in the ratchet path;
a spring that applies a force to move the J-slot piston towards the upper end of the tool such that both the first and the second set of flow paths are accessing the central bore, thereby permitting flow through both the first and the second set of flow paths, and
wherein moving the J-slot piston down causes the pins to slide along the ratchet path and the J-slot piston to rotate until the pins set in between peaks where either the first set of flow paths or the second set of flow paths are aligned with the flow channels.
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