Abstract: A method for logging a downhole formation in a wellbore. The method comprises drilling a wellbore with a drill bit coupled to a disconnect device. The disconnect device is then actuated to detach the drill bit from a portion of a conveyance. A logging operation is then performed between two portions of the disconnect device. The disconnect device may then be reattached.

Abstract: Apparatus and methods for selectively releasing a first wellbore component to a second wellbore component using a disconnect device. In one embodiment, the method includes coupling a disconnect device to a workstring and a downhole tool; performing a downhole operation using the downhole tool, and selectively releasing an upper portion of the disconnect device from a lower portion of the disconnect device, thereby releasing the downhole tool from the workstring. The method may also include reconnecting the upper portion of the disconnect device to the lower portion of the disconnect device. In one embodiment, the disconnect device is capable of transferring torque to the wellbore component.

Abstract: The present invention discloses a whipstock assembly (100) for use in forming a lateral borehole from a parent wellbore. The whipstock assembly comprises a body (122) and a deflection member 120) above the body. The deflection member includes aconcave portion (111) for deflecting a milling bit during a milling operation. Disposed on a perforation plate (110) portion of the concave portion is a raised surface feature (116). The raised surface supports a milling bit above the perforation plate portion during a milling operation. This, in turn, substantially prevents frictional contact between the milling bits and the perforation plate portion during a milling operation. The present invention also provides a novel method for manufacturing a whipstock in which a cavity portion is formed behind the perforation plate by milling out the backside of the deflection member and then joining a second back cover member to the whipstock body to complete the assembly.

Abstract: A method is provided that allows the operator to re-enter a primary wellbore from a lateral wellbore after the lateral wellbore has been completed. The method generally comprises the steps of locating a cutting device such as a milling bit adjacent a tubular such as a liner within a wellbore, rotating the milling bit while maintaining an axial position of the milling bit relative to the liner to initiate an opening, and rotating and axially advancing the milling bit to complete the opening. In addition, a bottom hole assembly that facilitates re-entry into the primary wellbore from a lateral wellbore is provided. The bottom hole assembly generally includes a drill collar or other heavy pipe structure, and a mill. The mill has a body and cutting structures. The cutting structures apply lateral force against a surrounding pipe to form an initial lip through the wall of the pipe.