Oilfield downhole wellbore section mill
View Patent ↗A section mill features extendable cutting blades and centering blades that are pressure actuated for sequential extension of the centering blades before the cutting blades. Applied pressure results in flow through a flow restriction that creates a force on return springs associated with the centering and the cutting blades. The springs allow extension of the centering blades before the cutting blades. Another spring returns a mandrel to the run in position on cessation of flow. The blades are extended or retracted with a rack and pinion drive system.
1. A tool for cutting tubular at a subterranean location, comprising:
a stationary housing;
at least one extendable cutting blade pivotally mounted on a fixed pivot on said housing;
at least one extendable centering blade pivotally mounted on a fixed pivot on said housing;
said centering blade extends to the tubular before said cutting blade;
said housing has a passage therethrough with a movable mandrel assembly disposed in said passage;
said mandrel assembly further comprising a mandrel sequentially moving spaced drive sleeves respectively associated with said centering blade and said cutting blade for extension of said centering blade before said cutting blade.
2. The tool of claim 1 , wherein:
said cutting and centering blades are axially spaced on said housing.
3. The tool of claim 1 , wherein:
said mandrel assembly responsively moves to applied pressure in said passage.
4. The tool of claim 1 , wherein:
said mandrel assembly is operatively connected to said cutting and centering blades such that axial movement of said mandrel assembly rotates said cutting and centering blades about respective pivotal connections for said cutting and centering blades.
5. The tool of claim 4 , wherein:
said mandrel assembly is connected to said cutting and centering blades with respective rack and pinion assemblies.
6. The tool of claim 5 , wherein:
said rack for said cutting and centering blades is located on said mandrel and said pinion for said cutting and centering blades is located at an end of said cutting and centering blades.
7. The tool of claim 6 , wherein:
said cutting and centering blades are pivotally mounted in wall openings in said housing.
8. The tool of claim 3 , wherein:
said mandrel assembly comprises a flow restriction in said passage that responds to flow therethrough with an applied axial force to said mandrel assembly.
9. The tool of claim 1 , wherein:
said drive sleeves are axially spaced and a biasing member is associated with each said drive sleeve.
10. The tool of claim 9 , wherein:
applied pressure in said passage overcomes said biasing member associated with said centering blade at a first predetermined pressure to extend said centering blade whereupon a further increase in pressure in said passage overcomes said biasing member associated with said cutting blade for subsequent extension of said cutting blade from said housing.
11. The tool of claim 10 , further comprising:
a mandrel assembly return spring to move said mandrel assembly axially for retraction of said cutting and centering blades on removal of pressure from said housing.
12. The tool of claim 10 , wherein:
removal of pressure in said passage allows said biasing members to sequentially retract said cutting blade followed by said centering blade.
13. The tool of claim 1 , wherein:
said at least one cutting blade comprises a plurality of circumferentially spaced cutting blades;
said at least one centering blade comprises a plurality of circumferentially spaced centering blades.
14. The tool of claim 13 , wherein:
said centering blades have arcuate ends.
15. The tool of claim 13 , wherein:
said cutting blades comprise a cut out side and a milling edge with carbide inserts extending to adjacent a periphery of said blades.
16. The tool of claim 13 , wherein:
said plurality of cutting blades and said plurality of centering blades are fully retracted into housing openings for run in.
17. The tool of claim 13 , wherein:
said plurality of cutting blades and said plurality of centering blades are pivotally mounted to said housing and actuated with an axially movable mandrel assembly in a passage of said housing through a rack and pinion operable connection between said mandrel assembly and said plurality of cutting blades and said plurality of centering blades.