An assembly for formation and completion of deviated wellbores is disclosed which includes a toolguide and a casing section which can be used together or separately. The toolguide includes a lower orienting section and an upper section having a sloping face, commonly known as the directional portion of a whipstock. The toolguide is coated with a material such as epoxy or polyurethane to provide a repairable surface and one which can be removed to facilitate removal of the toolguide from the well bore. The lower orienting section has a latch which extends radially outwardly from the section and can be locked in the outwardly biased position. The casing section of the present invention includes a sleeve which can be moved between a first position in which access to the window opening of casing section is not affected and a second position in which the main casing is sealed from the liner section of a deviated wellbore to provide a hydraulic seal against passage of fluids from outside the casing of the wellbore into the main casing.
12 Claims, 8 Drawing Sheets