Provided, in one aspect, is a whipstock. The whipstock may include a tubular having a longitudinal passageway extending along a length thereof, the tubular having a tapered face extending along at least a portion of the length; a support structure movably coupled to the tubular and extendable across the tapered face, wherein the support structure is operable to move from a first closed position closing the longitudinal passageway and a second open position exposing the longitudinal passageway; and a locking mechanism in the tubular for releasably holding the support structure in the first position.

A deflector assembly for an object in a well. The deflector assembly may include a tubular housing and a core plug. The tubular housing may include a window through a wall of the tubular housing, a deflector below the window. The deflector may include a cavity extending through an axial length of the deflector and a deflector angled surface that is shaped to direct the object toward the window. The core plug may be removably coupleable within the cavity and include a receptacle and a second angled surface that is shaped to direct the object toward the window. The second angled surface is aligned with the deflector angled surface. The core plug may be coupleable with the deflector so as to rotate with the deflector.

Systems, methods, and apparatus are disclosed allowing relative movement between downhole tools while remaining in electrical communication. In one example, a first tool comprising a first connector body is configured for connecting to a second connector body of a second tool. A sliding connector housing has an electrical strip axially arranged along the connector housing, wherein the first or second connector body is moveably secured to the connector housing in sliding electrical contact with the electrical strip. The first and second connector bodies are releasably connectable to each other, thereby allowing relative movement between the first and second tools via the connector housing while maintaining electrical and fluid communication between the first and second tools

A bottom hole assembly can include a mill and a whipstock having an upper end and an opening. A retractable pin extends from the mill into the opening. A section of the whipstock is separable from the whipstock in response to a force applied to the mill. The section is positioned between the opening and the upper end. A method can include positioning a bottom hole assembly in a well, the bottom hole assembly including a whipstock releasably secured to a mill, and then releasing the mill from the whipstock by separating a section of the whipstock from a remainder of the whipstock. Another method can include conveying a bottom hole assembly into a well, setting an anchor, then applying pressure to a hydraulic release mechanism, and then applying a force to the mill, thereby separating a section of the whipstock from a remainder of the whipstock.

A bottom hole assembly (BHA) includes a top sub-assembly configured to couple to a downhole conveyance to move into a wellbore that includes completion components secured in the wellbore; a drill bit configured to drill out and remove a first portion of a subset of the completion components; and an expandable reamer including a cutting assembly and configured to adjust between a retracted position in which a diameter of the cutting assembly is less than a diameter of a bore through at least one of the completion components and an activated position in which the diameter of the cutting assembly is greater than the diameter of the bore. The expandable reamer is further configured to remove a second portion of the subset of the completion components in the activated position.

A bottom hole assembly (BHA) includes a top sub-assembly configured to couple to a downhole conveyance to move into a wellbore that includes completion components secured in the wellbore; a drill bit configured to drill out and remove a first portion of a subset of the completion components; and an expandable reamer including a cutting assembly and configured to adjust between a retracted position in which a diameter of the cutting assembly is less than a diameter of a bore through at least one of the completion components and an activated position in which the diameter of the cutting assembly is greater than the diameter of the bore. The expandable reamer is further configured to remove a second portion of the subset of the completion components in the activated position.

Provided is a buoyant guide sub for use with a downhole oilfield conveyance. The buoyant guide sub, in one aspect, includes a hollow tubular structure, the hollow tubular structure including one or more tubular walls. The buoyant guide sub, according to at least one aspect, further includes a housing coupled to and slidable relative to the hollow tubular structure, the hollow tubular structure and the housing operable to form a pressurized chamber, the hollow tubular structure and housing having a combined mass per unit volume less than a specific gravity of 2.

Provided is a buoyant guide sub for use with a downhole oilfield conveyance. The buoyant guide sub, in one aspect, includes a hollow tubular structure, the hollow tubular structure including one or more tubular walls. The buoyant guide sub, according to at least one aspect, further includes a housing coupled to and slidable relative to the hollow tubular structure, the hollow tubular structure and the housing operable to form a pressurized chamber, the hollow tubular structure and housing having a combined mass per unit volume less than a specific gravity of 2.

A wellbore isolation system includes a junction positioned at an intersection of a first wellbore and a second wellbore, and a deflector disposed in the junction such that a path into the first leg of the junction is obstructed and engaged with the first leg of the junction to form a fluid and pressure tight seal. The junction includes a first leg extending downhole into the first wellbore, and a second leg extending downhole into the second wellbore.

A wellbore isolation system includes a junction positioned at an intersection of a first wellbore and a second wellbore, and a deflector disposed in the junction such that a path into the first leg of the junction is obstructed and engaged with the first leg of the junction to form a fluid and pressure tight seal. The junction includes a first leg extending downhole into the first wellbore, and a second leg extending downhole into the second wellbore.