CASING SIDETRACKS MADE EASY.

Milling a section for sidetracking cased well bores results in a comparatively large volume of metal cuttings that must be removed from the well. Another disadvantage of milling a section is that extra trips may be required to replace knives on the section mill. The authors discuss several commonly used techniques of sidetracking from a milled section, examining both their advantages and disadvantages. Main emphasis is placed on the use of the diamond sidetrack mill which has found several applications, the most common being the sidetracking of existing casings for several hundred feet so that a liner may be run and a completion made.