UNDERREAMER FOR INCREASING A WELLBORE DIAMETER

摘要

An underreamer for increasing a diameter of a wellbore. The underreamer may include a body with first and second cutter blocks coupled to the body. The first cutter block may have a recess formed therein, and the second cutter block may be positioned in the recess. The first and second cutter blocks may move between retracted and expanded states. In the retracted state, the first and second cutter blocks may have an outer diameter less than or equal to an outer diameter of the body. In the expanded state, the first and second cutter blocks may have different outer diameters, with each being greater than the outer diameter of the body. A method may include running the underreamer into a wellbore, expanding the first and second cutter blocks, and moving the underreamer axially in the wellbore to increase the diameter of the wellbore.

主权项

1. An underreamer, comprising:
a body; a first cutter block movably coupled to the body and having a recess therein, the first cutter block being movable between a retracted state and an expanded state, wherein in the retracted state an outer diameter of the first cutter block is less than or equal to an outer diameter of the body, and in the expanded state the outer diameter of the first cutter block is greater than the outer diameter of the body; and a second cutter block positioned within the recess of the first cutter block and movably coupled to the body, the first cutter block, or both, the second cutter block being movable between a retracted state and an expanded state, wherein in the retracted state an outer diameter of the second cutter block is less than or equal to the outer diameter of the body, and in the expanded state the outer diameter of the second cutter block is greater than the outer diameter of the first cutter block in its expanded state.