Underreamer for increasing a wellbore diameter

A downhole tool, comprising:

• a body defining an axial bore;
• a control unit within the axial bore, the control unit including:
• a control system adapted to process a signal;
• an activation system coupled to the control system and adapted to move in response to the control system processing the signal;
• and
• a valve within the axial bore and coupled to the activation system, the valve having a first configuration obstructing fluid flow through the valve and a second configuration allowing fluid flow through the valve;
• and
• a flow tube coupled to the valve and adapted to have fluid flow therethrough when the valve is in the second configuration, the fluid flowing along a radially inward path from the axial bore, through the valve, and into the flow tube.

A downhole tool, comprising:

• a body;
• a mandrel within the body, the mandrel having a port fluidly coupled to a channel;
• a reciprocating body within the body of the downhole tool and configured to move axially between first and second positions with respect to the mandrel, the reciprocating body blocking fluid flow through the port when in the first position and the reciprocating body allowing fluid flow through the port when in the second position;
• a piston within the body of the downhole tool and a chamber being defined between the piston and the mandrel, the piston including a port configured to align with the port of the mandrel when the reciprocating body is in the second position, the channel of the mandrel allowing a radially inward and axially downward flow a path of fluid communication to the chamber;
• and
• a plurality of expandable elements movably coupled to the body and configured to move from a radially inward position when the reciprocating body is in the first position to a radially outward position when the reciprocating body is in the second position.