| 摘要 |
Down hole assembly and method for forming a longitudinal window and a key-way in communication with the longitudinal window used in drilling multi-lateral well bores and for entry and reentry thereafter comprising, a first milling drill bit for milling the longitudinal window, a first whip stock having a guide surface, and orientation and positioning members located on the first whip stock for orienting and positioning tools to be used in forming the key-way in communication with the longitudinal window. A guide surface member is provided on the first whip stock member for guiding the first milling drill bit for milling a longitudinal window. A housing member for slidable mating with the first whip stock having a second drill bit member mounted in the housing member is provided for forming a down hole orientation key-way in communication with the longitudinally milled window. A second guide surface member positioned along the center line of the one surface guide member on the first whip stock is provided for guiding the second drill bit to drill a down hole orientation key-way in communication with the longitudinal window. A second whip stock having a forming member for forming an up hole orientation key-way in communication with the longitudinally milled window is provided with at least one guide surface member on the second whip stock member for guiding the forming member for forming the up hole orientation key-way in communication with the longitudinal window.
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