Special Mills

STARTING MILL : OTI’s Starting Mills are used in conjunction with whipstock. These tools are used for orientation of the whipstock. This tool is initially used to lower the whipstock into the setting position prior to beginning the window milling operation. After setting the whipstock and shearing the shear bolt (setting stud), the Starting Mill’s taper rides down and against the pilot lug on the whipstock’s concave side forcing the mill to start cutting through the casing and into the formation.

Ordering Instructions:

When ordering or requesting quotations on starting mills, please specify:

  1. Size and weight if casing to be milled.
  2. Whipstock Dia.
  3. Dressed Dia. of the Mill.
  4. Top Pin Connection.
  5. Length.
  6. Any special feature.

WINDOW MILL : OTI’s Window Mills are used for cutting the window as a follow-up mill to the Starting Mill in whipstock operations. It moves down the angled face of the whip stock, milling out the casing for the entire length of the whipstock face. It is designed to grind the casing like a fine metal powder instead of metal shavings or chips. It can be used alone or in conjunction with a Watermelon Mill on a joint of drill pipe.

Ordering Instructions:

When ordering or requesting quotations on window mills, please specify:

  1. Size and weight if casing to be milled.
  2. Whipstock Dia.
  3. Dressed Dia. of the Mill.
  4. Top Pin Connection.
  5. Length.
  6. Any special feature.

WATERMELON / STRING MILL : OTI’s Watermelon Mills can be utilized in several bottom-hole assemblies during the window cutting operation. It is designed to mill up or down as it elongates and dresses the casing window. It can be used directly above the Window Mill or Tapered Mill, as well as above the first drill collar while drilling the first several feet of formation after the casing window is complete.
OTI’s String Mills can be used either as a stabilizer or as an elongating tool to assist in the milling of a longer and smoother casing window. It is run directly above the Window Mill in the whipstock operation. It is often used in conjunction with drill collars and taper mills when reaming out a tight hole in casing or formation.
Ordering Instructions:

When ordering or requesting quotations on watermelon / string mills, please specify:

  1. Size and weight if casing to be milled.
  2. Whipstock Dia.
  3. Dressed Dia. of the Mill.
  4. Top Pin & Bottom Box Connection.
  5. Length.
  6. Any special feature.