Abstract: The present invention provides a tool for use in wellbores. The tool is operated by the wellbore hydrostatic pressure. The tool includes one or more devices that operate when a mechanical force is applied to such devices. The tool includes at least one atmospheric chamber. A setting member disposed in the tool is utilized to provide the mechanical force in response to the application of the hydrostatic pressure thereto. Prior to activating the tool, the setting member is locked or restrained in an inoperative position. To operate the device, the tool is placed at a suitable location in the wellbore. The atmospheric chamber is charged with the wellbore fluid, which releases the setting member from its restrained or locked position, subjecting the setting member to the wellbore hydrostatic pressure, thereby providing the mechanical force to operate at least one of the devices.

Abstract: An apparatus and method of milling a liner extending from a deviated wellbore into a main wellbore is disclosed. The liner is inserted through a window and cemented in place with the cement extending back into the main wellbore. Mechanisms are provided on the liner to keep it away from the main wellbore casing wall to facilitate the proper operation of the washover tool. A top end taper is provided to help the washover tool reorient over the tubular liner if milling requires more than one trip into the well. A diverter is insertable prior to installation of the liner to assist in getting the liner to extend through a window. Upon milling through the liner, the washover tool straddles the diverter and latches into it to facilitate not only the removal of the diverter but also the entrapment of any debris created by the milling operation. Suitable sealing is provided with the diverter to keep the cement away from the latching mechanism during the cementing operation.

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.