| 摘要 |
An assembly for drilling at least one lateral well from a well bore having a longitudinally premilled window formed therein and having a first orientation key-way member formed in the premilled window and in communication with the premilled window and located on the down hole portion of the premilled window and having a second orientation key-way member formed in the premilled window and in communication with the premilled window and located on the up hole portion of the premilled window. The window is provided with a cover for closing the premilled window and first and second orientation key way members from fluid communication. A whip stock is provided for drilling at least one multilateral well. A key is provided which is spring loaded for being received into the premilled window and guided into locking engagement in the first orientation key way as the key is lowered down hole. A method of using such assembly comprising adding a premilled window to the casing string and setting it and hen running an orientation tool to orientate the window and cememting the well casing. The cement, temporary orientation key, temporary mule shoe, and the cover are drilled out and a whip stock is set by landing the key in the key-way while lowering the whip stock. Once the whip stock is set the lateral well is drilled. Reentry is achieved by having a spring loaded key received into the premilled window and engaged upon up hole movement.
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