Method and apparatus for identifying a bad mill track, and borehole system
A method for identifying a bad mill track, including running a whipstock assembly, including a whipstock, an anchor attached to the whipstock and a debris management device attached to the whipstock, the device including a tracer, to a kick-off point in a borehole, running a mill along the whipstock, and monitoring a cuttings stream for presence of the tracer. A whipstock assembly including a whipstock, an anchor attached to the whipstock, a debris management device attached to the anchor, the device inhibiting the migration of debris from a mill during use from migrating downhole of the anchor, and a tracer disposed in contact with the debris management device, the tracer configured for release from the device in the event the device is damaged. A borehole system, including a borehole in a subsurface formation, a string in the borehole, and a whipstock assembly disposed within or part of the string.
1 . A method for identifying a bad mill track, comprising:
running a whipstock assembly, including a whipstock, an anchor attached to the whipstock and a debris management device attached to the whipstock and configured to catch rather than drop debris created by a mill run against the whipstock, the device including a tracer, to a kick-off point in a borehole;
running a mill along the whipstock
catching debris with the debris management device, the debris management device comprising a material and the tracer comprising a material, the material of the tracer and the material of the device being mixed at a manufacturing stage of the whipstock assembly; and
monitoring a cuttings stream for presence of the tracer.
2 . The method as claimed in claim 1 , wherein the monitoring includes applying a light source to the cuttings stream.
3 . The method as claimed in claim 2 , wherein the light source includes ultraviolet light or black light.
4 . The method as claimed in claim 1 , wherein the tracer is florescent.
5 . The method as claimed in claim 1 , wherein in the event the mill follows a bad track and mills the debris management device the method includes releasing the tracer by the milling of the debris management device and identifying the tracer at a remote location.
6 . The method as claimed in claim 5 , wherein the remote location is a surface location.
7 . A whipstock assembly comprising:
a whipstock;
an anchor attached to the whipstock;
a debris management device attached to the anchor and extending radially outwardly from the anchor, the device inhibiting the migration of debris from a mill during use from migrating downhole of the anchor; and
a tracer disposed in contact with the debris management device, the tracer configured for release from the device in the event the device is damaged, wherein the debris management device comprises a material and the tracer comprises a material, the material of the tracer and the material of the device being mixed at a manufacturing stage of the whipstock assembly.
8 . The assembly as claimed in claim 7 , wherein the tracer is human-eye visibly distinct from cuttings.
9 . The assembly as claimed in claim 7 , wherein the tracer is a fluorescent material.
10 . A borehole system, comprising:
a borehole in a subsurface formation;
a string in the borehole; and
a whipstock assembly as claimed in claim 7 disposed within or as a part of the string.