Abstract: Sidetracking system including dual-action hydraulically operable anchor for positioning a whipstock in a wellbore and a bi-mill for milling an opening through a wellbore casing in a preplanned lateral drilling path in departure from the wellbore axis and through the wellbore casing or rock formation and in the direction of the drilling path. The anchor's upper and lower hydraulic pistons provide two compressive forces with a third mechanical force being applied from the attached whipstock and workstrin all forces being additive, to compressively set the floating mandrel. The three additive forces function to fix the anchor in the wellbore with extremely great force. The bi-mill mills an opening through a wellbore casing in a preplanned lateral drilling path in departure from the wellbore axis and through the wellbore casing or rock formation and in the direction of the drilling path.

Abstract: A dual-action hydraulically operable anchor includes a hydraulic anchor body for positioning a whipstock in a wellbore. A split clamp retains an upper sub and the hydraulic anchor body. A lower cap guides the hydraulic anchor within the wellbore. The floating mandrel transmits a hydraulic fluid into the fixed housing, transmitting compressive force from the upper hydraulic piston or from mechanical force applied to the whipstock above and adjoining the hydraulic anchor. The lower hydraulic piston operates along the floating mandrel using transmitted hydraulic fluid. A T-slot adapter and a slip move from a flush position along the fixed housing to an extended position along the fixed housing such that the slip firmly engages the wellbore to hold the hydraulic anchor and the whipstock in a fixed position for providing a path for lateral drilling outside the wellbore.

Abstract: A bi-mill mills an opening through a wellbore casing in a preplanned lateral drilling path in departure from the wellbore axis and through the wellbore casing or rock formation and in the direction of the drilling path. The bi-mill provides increase debris removal and cutting surfaces and includes an assembly having a lead mill and a follow mill and attaches to the wellbore whipstock. The lead mill further includes fluid passageways leading from the lead mill and exiting the nose of the lead mill. Debris removal channels channel milled debris away from the lead mill and in the direction of the follow mill form in a helical configuration for guiding debris milled by lead mill inserts along the debris removal channels. The lead mill and follow mill continue milling through the wellbore casing and into the underground rock formation a distance sufficient to initiate the preplanned drilling path.

Abstract: A dual-action hydraulically operable anchor includes a hydraulic anchor body for positioning a whipstock in a wellbore. A split clamp retains an upper sub and the hydraulic anchor body. A lower cap guides the hydraulic anchor within the wellbore. The floating mandrel transmits a hydraulic fluid into said fixed housing, transmitting compressive force from the upper hydraulic piston or from mechanical force applied to the whipstock above and adjoining the hydraulic anchor. The lower hydraulic piston operates along the floating mandrel using transmitted hydraulic fluid. A T-slot adapter and a slip move from a flush position along said fixed housing to an extended position along said fixed housing such that said slip firmly engages the wellbore to hold said hydraulic anchor and said whipstock in a fixed position for providing a path for lateral drilling outside the wellbore.