Provided, in one aspect, is an anchor for use with a downhole tool in a wellbore. The anchor, according to this aspect, may include a base pipe; and one or more expandable chambers positioned radially about the base pipe. The one or more expandable chambers may, in some aspects, be configured to move from a first collapsed state to a second activated state; and the one or more expandable chambers may be operable to handle at least 20.7 Bar of internal pressure in the second activated state to engage a wall of a wellbore.

A drilling wedge that has, in addition to a normal connector rod, two wings that extend from the sides of the wedge. These wings are angular members that fill much of the space in the larger casing around the wedge. These wings prevent a milling assembly from sliding past the wedge or from moving off to the side, where an exit through the pipe or casing in the wrong place can occur. Instead, the wings help to keep the milling assembly in the proper position on the tray of the wedge to ensure that the milling assembly reaches the proper exit point in the casing. The wings are retracted when the HEW is deployed through the narrower pipe. Once the HEW is properly positioned, the guide cone is extended and the wings are deployed.

A mill including a housing having a fluid bypass pathway, a milling feature at a longitudinal end of the housing, a chamber defined by the housing, and a piston disposed in communication with the chamber, the piston defining a fluid passageway initially aligned with the fluid bypass pathway, the piston responsive to pump pressure to move toward the milling feature, the movement misaligning the fluid passageway with the fluid bypass pathway.

A drill bit for drilling a bore, the drill bit comprising: an outer housing; a primary cutting structure defining a cutting plane of a first diameter; a flow path arranged to let drilling fluid flow through the drill bit; and a deployable blade assembly at least partially located within the outer housing, the deployable blade assembly comprising a cutting structure and being arranged to be axially movable from a first position, in which the deployable cutting structure is recessed with respect to the primary cutting structure, towards the cutting plane, to a second position; wherein when the deployable blade assembly is in the second position, the deployable cutting structure defines a cutting diameter which is less than or equal to the first diameter.

A bottom hole assembly for use in a subterranean well can include a whipstock, a mill releasably secured to the whipstock, an antenna, and a release mechanism configured to release the mill from the whipstock in response to a predetermined radio frequency signal received by the antenna. A method can include positioning a bottom hole assembly in a well, the bottom hole assembly including a mill and a whipstock releasably secured to the mill, and then releasing the mill from the whipstock by displacing a radio frequency identification tag into the bottom hole assembly. A well system can include a bottom hole assembly comprising an anchor, a whipstock and a mill, and a radio frequency identification tag displaceable with fluid flow into the bottom hole assembly.

A collapsible bullnose assembly may include a mandrel, a bullnose secured to a distal end of the mandrel, a lower ramp disposed about the mandrel adjacent the bullnose and having a first ramped surface, and an upper ramp slidably disposed around and releasably secured to the mandrel. The upper ramp may have a second ramped surface axially offset from the first ramped surface. The collapsible bullnose assembly may further include a collapsible guide member having opposing ends initially supported on the first and second ramped surfaces and protruding radially outwardly of the bullnose. The collapsible guide member may be actuatable to a radially collapsed orientation in response to axially shifting the upper ramp along the mandrel to a released position away from the lower ramp.

A retrievable whipstock assembly for a wellbore includes a whipstock including a longitudinal body and an anchor connection, a deflection surface provided on the longitudinal body with a first engagement element, and a drilling assembly including a drill housing and a second engagement element. The second engagement element is selectively extendible between a recessed position and an extended position. In the extended position the second engagement element is engageable with the first engagement element.

A method of positioning a bottom hole assembly in a wellbore includes lowering the bottom hole assembly into the wellbore. The bottom hole assembly has a whipstock, a downhole tool, and a cleaning tool having a cleaning element. The method also includes cleaning at least a portion of a wall of the wellbore using the cleaning tool, and activating the downhole tool to engage the cleaned portion of the wall.

A multilateral well access system includes a directional guide and a mating surface profile. The directional guide includes a main body and an outer surface profile disposed on the main body. The main body defines a guide surface oriented non-parallelly to an elongate axis of the main body and a bore passing through the main body along the elongate axis. The mating surface profile is formed complementary to the outer surface profile of the directional guide and is engaged with the outer surface profile to secure the directional guide in a fixed position.

A whipstock assembly including a main body defining an axial direction extending through the main body, a circumferential direction, and a radial direction transverse to the axial direction, and a ramp body pivotally coupled to the main body, the ramp body defining a ramp surface that is oriented transverse to the radial direction, and where the ramp body is movable between a retracted position and an extended position, where the ramp surface is further from the main body in the axial direction in the extended position as compared to the retracted position and the ramp body is rotatable with respect to the main body about the circumferential direction.