Intelligent section mill, method, and system

1. A section mill comprising:

a housing;

a cutter pivotally connected to the housing;

a drive piston operably connected to the cutter to radially expand or retract the cutter depending upon longitudinal position of the drive piston relative to the housing; and

a limit configuration including a pushblock in operable contact with the drive piston to limit drive piston stroke responsive to hydraulic pressure on the drive piston, wherein the pushblock contacts a shuttle dog that is in turn in contact with the drive piston and limits movement of the drive piston based upon shuttle dog position.

2. The mill as claimed in claim 1 wherein the limit configuration comprises an electric motor and a driver.

3. The mill as claimed in claim 2 wherein the driver is a lead screw and follower.

4. The mill as claimed in claim 1 wherein the pushblock has a plurality of steps thereon.

5. The mill as claimed in claim 1 wherein the drive piston includes a plurality of lands selectively interactive with the shuttle dog.

6. The mill as claimed in claim 1 wherein the mill includes a sensory apparatus to sense condition of structure radially outwardly of a casing to be cut.

7. The mill as claimed in claim 6 wherein the sensory apparatus is an acoustic sensor.

8. The mill as claimed in claim 1 wherein the mill employs log data to position the limit configuration.

9. A method for cutting casing comprising:

determining condition of a structure radially outward of a casing to be cut;

selecting an amount of expansion of a cutter based upon the determining, wherein the selecting includes limiting an actuation stroke to limit radial expansion of the cutter, and wherein the limiting is running an electric motor to move a pushblock mechanically connected to a drive piston that physically limits movement of the drive piston; and

cutting the casing.

10. The method as claimed in claim 9 wherein the determining is by reading a log.

11. The method as claimed in claim 9 wherein the determining is by sensing structure radially outside of the casing to be cut.

12. The method as claimed in claim 9 wherein the selecting includes communicating a signal to a limit configuration that limits the expansion of the cutter.

13. The method as claimed in claim 12 wherein the communicating is from a controller local to the cutter.

14. A borehole system comprising:

a borehole in a subsurface formation;

a string in the borehole; and

a section mill as claimed in claim 1 disposed in the borehole.

15. The borehole system as claimed in claim 14 further including a controller in communication with the limit configuration.

16. The borehole system as claimed in claim 15 wherein the controller is disposed in the same housing as the limit configuration.

17. A section mill comprising:

a housing;

a cutter pivotally connected to the housing;

a drive piston operably connected to the cutter to radially expand or retract the cutter depending upon longitudinal position of the drive piston relative to the housing; and

a limit configuration in operable contact with the drive piston to limit drive piston stroke responsive to hydraulic pressure on the drive piston, wherein the mill employs log data to position the limit configuration.

18. A method for cutting casing comprising:

determining condition of a structure radially outward of a casing to be cut;

selecting an amount of expansion of a cutter based upon the determining, wherein the selecting includes communicating a signal to a limit configuration that limits the expansion of the cutter; and

cutting the casing.