Downhole wireline machining tool string

A downhole wireline machining tool string for increasing an inner diameter of a well tubular metal structure in a well or cutting out a piece, the downhole wireline machining tool string having a longitudinal axis and comprising:

• a rotatable tool part comprising a machining tool having a first end part, a second end part with a drill bit, a diameter and a circumference, and
• a stationary tool part comprising:
• a wireline, and
• a driving unit configured to rotate the rotatable tool part and electrically powered through the wireline,
• wherein the machining tool comprises a body having an outer face and a fastener configured to fasten a machined piece, the fastener being configured to resiliently flex to engage an inside diameter of the machined piece drilled by the drill bit, at which point the fastener is non-rotatably fixed to the inside diameter of the machined piece whilst the rotatable part continues to rotate relative to the fastener, and
• wherein the machining tool has a bore arranged coincident with a centre axis of the machining tool around which the rotatable tool part rotates, the bore having a bore inlet located at the front of the tool string and extending into the second end part.

A machining tool for increasing an inner diameter of a well tubular metal structure in a well, comprising:

• a body,
• a drill bit,
• a fastener circumferenting the body,
• a core drill having a circumferential wall with inserts, said circumferential wall circumferenting the body, and
• a wireline to electrically power rotation of the drill bit,
• wherein the machining tool includes a leading end structured to engage a restriction extending from or formed as part of the inner diameter of the well tubular structure, the machining tool including a bore inlet extending from the front of the tool and into the leading end to reduce engagement between the leading end and the restriction, the bore inlet being adapted to receive a machined piece of the restriction during machining operation, and
• wherein the fastener is configured to engage an inside diameter of the machined piece, at which point the fastener is non-rotatably fixed to the inside diameter of the machined piece whilst the drill bit continues to rotate relative to the fastener.