Actuation assembly and method for actuating a downhole tool

A method for actuating a downhole tool having a tool housing and an actuation member, the method comprising:

• providing a downhole power unit having a power unit housing and a moveable shaft;
• providing a stroke extender having an extender housing and an extender mandrel;
• operably associating the power unit housing with the extender housing and operably associating the moveable shaft with the extender mandrel;
• operably associating the extender housing with the tool housing and the actuation member and operably associating the extender mandrel with the actuation member;
• and
• oscillating the moveable shaft in first and second longitudinal directions relative to the power unit housing which causes oscillation
• the extender mandrel in the first and second longitudinal directions relative to the extender housing
• which causes progressive shifting of the actuation member in the first direction relative to the tool housing, thereby actuating the downhole tool, wherein the downhole tool does not include a J-slot mechanism.

An actuation assembly for setting a through tubing bridge plug having an adaptor and an actuation rod, the actuation assembly comprising:

• a downhole power unit having a power unit housing and a moveable shaft;
• and
• a stroke extender having a extender housing and an extender mandrel longitudinally movable within the extender housing, the power unit housing operably associated with the extender housing, the moveable shaft operably associated with the extender mandrel;
• wherein the extender housing is operably associated with the adaptor and the actuation rod;
• wherein the extender mandrel is operably associated with the actuation rod such that oscillatory uphole and downhole movement of the moveable shaft relative to the power unit housing causes oscillatory movement of the extender mandrel relative to the extender housing which shifts the actuation rod in the uphole direction relative to the adaptor, thereby setting the through tubing bridge plug;
• and wherein the through tubing bridge plug does not include a J-slot mechanism.