Abstract: In accordance with the present invention, a plurality of methods and devices are provided for solving important and serious problems posed by lateral (and especially multilateral) completion including methods and devices for re-entering selected lateral wells to perform completions work, additional drilling, or remedial and stimulation work. Various methods and devices are provided for assisting in the location and re-entry of lateral wells. Such re-entry devices include permanent or retrievable deflector (e.g., whipstock) devices. Preferably, the re-entry methods of this invention permit the bore size of the lateral wells to be the same or substantially the same bore size as the vertical wells.

Abstract: In accordance with the present invention, a plurality of methods and devices are provided for solving important and serious problems posed by lateral (and especially multilateral) completion in a wellbore including methods and devices for isolating a lateral well from other lateral branches in a multilateral well so as to prevent migration of fluids and to comply with regulations regarding the separate production of different production zones. Various methods and devices are provided for fluid isolation of a lateral well from other lateral wells and for separate production from a lateral well without commingling the production fluids. These methods include the use of a side pocket mandrel, whipstocks with sealable bores and valving techniques wherein valves are located at the surface or downhole at the junction of a particular lateral.