Patent ID: 9316079
Filing Date: 2016-04-19
CPC Classification: E21B

Claim Text:
1. A milling assembly for milling an orifice in a well casing, comprising: a flexible joint assembly that includes a drive yoke couplable to a drive tube that applies a rotational driving force to the flexible joint assembly, the flexible joint assembly including a plurality of straight yoke assemblies, a plurality of split yoke assemblies, and a cutter head, the drive yoke being pivotally joined to one of the plurality of straight yoke assemblies through a universal block, each of the plurality of straight yoke assemblies being pivotally joined to at least one of the split yoke assemblies through additional universal blocks, a distal most of the plurality of split yoke assemblies being pivotally joined with the cutter head through another universal block; a cylindrical split shoe having a passage for guiding the flexible joint assembly to bend toward an internal surface of the well casing where the orifice is to be milled; and a tubular sleeve that is disposed around the flexible joint assembly, the tubular sleeve being coupled to the drive tube by at least one shear pin, such that in response to the tubular sleeve engaging a proximal end of the cylindrical split shoe, the at least one shear pin is sheared through causing a momentary decrease in a weight of the drive tube that is detectable on a surface above the well casing, indicating that the flexible joint assembly is proximate to a location where the orifice is to be milled through the well casing, the cutter head being disposed at a distal end of the flexible joint assembly to contact the internal surface of the well casing and to mill the orifice through the well casing as the drive tube rotates the flexible joint assembly and the cutter head.