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US 8,042,613 B2Granted
Drilling head for reboring a stuck valve
AssigneeWeltec A/S
InventorsJørgen Hallundbaek, Sven Karsten Jensen, Thomas Sune Andersen
Life of this patent
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Abstract
A drilling head, method of drilling, and use of the drilling head, for reboring a stuck valve or drilling into the formation downhole and, in particular a drilling tool having a drilling head and a driving unit. The drilling head includes a hole saw beside a drill bit for cutting out a piece from the stuck valve. A drilling system includes the drilling tool and a driving tool for moving the drilling tool downhole.
Claims22
A downhole drilling head, comprising:
- a hole saw having a cylindrical body with a circumferential rim and a longitudinal axis going through a centre of the cylindrical body, and
- a drill bit extending along the longitudinal axis and through the centre of the cylindrical body,
- wherein the circumferential rim has at least one cutting edge inclining at least partly towards the longitudinal axis of the cylindrical body, and
- wherein the cutting edge is rotatable and capable of cutting a piece out of at least one of a stuck metal valve or a formation downhole, and
- wherein the cutting edge inclines at least partly towards the longitudinal axis of the cylindrical body so that an inner diameter (D) of the body decreases at least 2% forming a tip diameter (d) at a tip of the cutting edge.
2 more elements
A downhole drilling head, comprising:
- a hole saw having a cylindrical body with a circumferential rim and a longitudinal axis going through a centre of the cylindrical body, and
- a drill bit extending along the longitudinal axis and through the centre of the cylindrical body,
- wherein the circumferential rim has at least one rotatable cutting edge capable of cutting a piece out of a stuck valve or a formation downhole, and
- wherein the drill bit has a retractable projection;
- when drilling, the projection is retracted when the projection is passed by the piece cut out by the cutting edge, the projection subsequently returning to a projected position, and the piece thus returning with the drilling bit when the drilling ends, wherein at least a part of the retractable projection is located within the cylindrical body of the hole saw.
2 more elements
Dependencies are inferred from the claim text.