MILLING TOOLS WITH A SECONDARY ATTRITION SYSTEM

摘要

Milling systems, tools, and methods include using a mill with secondary attrition system to re-mill cuttings and other debris away from the face of the mill. The secondary attrition system may be located uphole of the mill may be used to stage conditioning and re-sizing of debris. After debris is generated by the mill, the secondary attrition system may re-mill the debris to a finer size before allowing the debris to pass out of the sleeve. The debris may be re-milled by secondary cutting elements while within an annular gap positioned radially between the sleeve and a drive shaft for the mill. The annular gap may have a variable width as a result of a tapered outer surface of the drive shaft and/or a tapered inner surface of the sleeve. The variable width may cause debris to be re-milled into increasingly finer sizes.

主权项

1. A secondary attrition system for a milling system, comprising:
a sleeve having an inner surface and an outer surface; a tubular component within the sleeve, the tubular component having an outer surface cooperating with the inner surface of the sleeve to define a gap having a variable width along at least a portion of a length of the tubular component; and at least one cutting element coupled to the inner surface of the sleeve or the outer surface of the tubular component.