Abstract: Milling systems, tools, and methods include using a mill with secondary attrition system to re-mill cuttings and other debris away from the face of the mill. The secondary attrition system may be located uphole of the mill may be used to stage conditioning and re-sizing of debris. After debris is generated by the mill, the secondary attrition system may re-mill the debris to a finer size before allowing the debris to pass out of the sleeve. The debris may be re-milled by secondary cutting elements while within an annular gap positioned radially between the sleeve and a drive shaft for the mill. The annular gap may have a variable width as a result of a tapered outer surface of the drive shaft and/or a tapered inner surface of the sleeve. The variable width may cause debris to be re-milled into increasingly finer sizes.

Abstract: A departure device couples to a bit using a connector that facilitates release of the bit from the departure device. The connector may be more millable than the departure device and can transmit axial and torque loads between the bit and the departure device. The connector may include a material having lesser strength or hardness than the departure device, and may be millable by the bit. Another example connector may have connection points with the bit, and a movable member of the departure device may a force to the connector and contribute to releasing the connection between the bit and the departure device. A tensile connector between the bit and the movable member may apply a tension force to the movable member, urging the movable member toward an extended position in which the movable member is aligned coherently with a sloped face of the departure device.

Abstract: A milling tool includes a cutting block in a recess in a tool body. The cutting block is configured to extend radially outward from and retract radially inward toward the tool body. The milling tool further includes a milling blade in a recess or cut-out in the cutting block. The milling blade is configured to extend radially outward from and inwards toward the cutting block. One or more links may couple the milling blade to the tool body to cause the milling blade to move radially relative to the cutting block when the cutting block moves radially relative to the tool body. The milling tool may be used as a dual string section mill to remove any of an inner casing, an outer casing, or cement between the inner and outer casings.

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 sidetracking assembly employs a running tool for engaging the whipstock. A cement tube flows low-viscosity fluid through the whipstock to set a hydraulically actuable anchor and to transmit fluid cement further downhole in order to set a cement plug. A latch dog releasably associates the running tool with the whipstock. The latch dog disengages the running tool from the whipstock after the anchor is set. The running tool and cement tube can be raised a designed distance using a first pull tension, indicating that the cement tube is not restrained and that therefore an operation to pump cement to form a cement plug below the assembly may be executed. Following the cementing operation, a greater pull tension can be applied to release the cement tube from the whipstock, permitting complete withdrawal of the reusable running tool and cement tube from the wellbore.

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: Milling systems, tools, and methods include using a mill with secondary attrition system to re-mill cuttings and other debris away from the face of the mill. The secondary attrition system may be located uphole of the mill may be used to stage conditioning and re-sizing of debris. After debris is generated by the mill, the secondary attrition system may re-mill the debris to a finer size before allowing the debris to pass out of the sleeve. The debris may be re-milled by secondary cutting elements while within an annular gap positioned radially between the sleeve and a drive shaft for the mill. The annular gap may have a variable width as a result of a tapered outer surface of the drive shaft and/or a tapered inner surface of the sleeve. The variable width may cause debris to be re-milled into increasingly finer sizes.

Abstract: A sidetracking assembly employs a running tool for engaging the whipstock and providing structural support and fluid communication through the running tool. A cement tube operates in selective fluid communication with the running tool body for flowing low-viscosity fluid through the whipstock to set a hydraulically actuable anchor and to transmit fluid cement further downhole in order to set a cement plug. A latch dog releasably associates the running tool with the whipstock. A pressure-activated withdrawal mechanism releases the latch dog to disengage the running tool from the whipstock after the anchor is set. The running tool and cement tube can be raised a designed distance using a first pull tension, indicating that the cement tube is not restrained and that therefore an operation to pump cement to form a cement plug below the assembly may be executed.

Abstract: Milling systems, tools, and methods include using a mill with secondary attrition system to re-mill cuttings and other debris away from the face of the mill. The secondary attrition system may be located uphole of the mill may be used to stage conditioning and re-sizing of debris. After debris is generated by the mill, the secondary attrition system may re-mill the debris to a finer size before allowing the debris to pass out of the sleeve. The debris may be re-milled by secondary cutting elements while within an annular gap positioned radially between the sleeve and a drive shaft for the mill. The annular gap may have a variable width as a result of a tapered outer surface of the drive shaft and/or a tapered inner surface of the sleeve. The variable width may cause debris to be re-milled into increasingly finer sizes.

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.

Abstract: A milling tool includes a cutting block in a recess in a tool body. The cutting block is configured to extend radially outward from and retract radially inward toward the tool body. The milling tool further includes a milling blade in a recess or cut-out in the cutting block. The milling blade is configured to extend radially outward from and inwards toward the cutting block. One or more links may couple the milling blade to the tool body to cause the milling blade to move radially relative to the cutting block when the cutting block moves radially relative to the tool body. The milling tool may be used as a dual string section mill to remove any of an inner casing, an outer casing, or cement between the inner and outer casings.

Abstract: A departure device couples to a bit using a connector that facilitates release of the bit from the departure device. The connector may be more millable than the departure device and can transmit axial and torque loads between the bit and the departure device. The connector may include a material having lesser strength or hardness than the departure device, and may be millable by the bit. Another example connector may have connection points with the bit, and a movable member of the departure device may a force to the connector and contribute to releasing the connection between the bit and the departure device. A tensile connector between the bit and the movable member may apply a tension force to the movable member, urging the movable member toward an extended position in which the movable member is aligned coherently with a sloped face of the departure device.

Abstract: A dual string section milling tool includes a cutting block deployed in an axial recess in a tool body. The cutting block is configured to extend radially outward from and retract radially inward towards the tool body. The cutting block is further configured to remove a cement layer in a wellbore. The dual string section milling tool further includes a milling blade deployed in an axial slot disposed in the cutting block. The milling blade is configured to extend radially outward from and inwards towards the cutting block. The milling blade is further configured to cut and mill a section of casing string. The dual string section milling tool may be further configured to simultaneously remove cement and mill a wellbore tubular.

Abstract: A downhole tool for increasing a cross-sectional area of a wellbore is provided. The downhole tool may include a first drilling assembly including a first reaming tool for selectively increasing the cross-sectional area of the wellbore. A first ball seat may receive a first ball. At least one of the first ball seat and the first ball may deform to allow the first ball to pass through the first ball seat when a predetermined pressure is applied thereto. A first piston may be coupled to the first ball seat. The first ball seat and the first piston may stroke when the first ball is received within the first ball seat, thereby actuating the first reaming tool between an active state and an inactive state.

Abstract: A downhole tool includes a radial expansion assembly deployed about, and configured to rotate substantially freely with respect to, a tool mandrel. The expansion assembly includes at least one stabilizer block configured to extend radially outward from the mandrel into contact with a wellbore casing string. When deployed between uphole and downhole cones, the stabilizer block includes a plurality of angled splines configured to engage corresponding splines on the cones. Relative axial motion between the stabilizer block and the cones causes a corresponding radial extension or retraction of the stabilizer block.

Abstract: Milling systems, tools, and methods include using a mill with a barrier to promote re-circulation of debris and cuttings to the face of the mill. The face of the mill may include cutting elements. A barrier may obstruct the flow of cuttings and debris away from the face to re-circulate the cutting and debris to promote re-milling of the cuttings and debris by the cutting elements of the face of the mill. The barrier may include a hydraulic barrier formed by fluid expelled from nozzles in or above the mill. A secondary attrition system uphole of the mill may also be used to stage conditioning and re-sizing of cuttings and debris. After debris and cuttings pass through the barrier, the secondary attrition system may re-mill the cuttings and debris to a finer size before allowing the cuttings and debris to pass into the wellbore annulus for transport to the surface.

Abstract: Milling systems, tools, and methods include using a mill with secondary attrition system to re-mill cuttings and other debris away from the face of the mill. The secondary attrition system may be located uphole of the mill may be used to stage conditioning and re-sizing of debris. After debris is generated by the mill, the secondary attrition system may re-mill the debris to a finer size before allowing the debris to pass out of the sleeve. The debris may be re-milled by secondary cutting elements while within an annular gap positioned radially between the sleeve and a drive shaft for the mill. The annular gap may have a variable width as a result of a tapered outer surface of the drive shaft and/or a tapered inner surface of the sleeve. The variable width may cause debris to be re-milled into increasingly finer sizes.

Abstract: A system and method facilitate sidetracking by eliminating one or more trips downhole. A sidetracking system includes a whipstock assembly and a stinger assembly. The stinger assembly has a stinger which extends at least partially through the whipstock assembly. The stinger is coupled to a sub of the sidetracking system by a releasable latch mechanism, such as a shear pin or collet.

Abstract: A dual string section milling tool includes a cutting block deployed in an axial recess in a tool body. The cutting block is configured to extend radially outward from and retract radially inward towards the tool body. The cutting block is further configured to remove a cement layer in a wellbore. The dual string section milling tool further includes a milling blade deployed in an axially slot disposed in the cutting block. The milling blade is configured to extend radially outward from and inwards towards the cutting block. The milling blade is further configured to cut and mill a section of casing string. The dual string section milling tool may be further configured to simultaneously remove cement and mill a wellbore tubular.

Abstract: A dual string section milling tool includes a cutting block deployed in an axial recess in a tool body. The cutting block is configured to extend radially outward from and retract radially inward towards the tool body. The cutting block is further configured to remove a cement layer in a wellbore. The dual string section milling tool further includes a milling blade deployed in an axially slot disposed in the cutting block. The milling blade is configured to extend radially outward from and inwards towards the cutting block. The milling blade is further configured to cut and mill a section of casing string. The dual string section milling tool may be further configured to simultaneously remove cement and mill a wellbore tubular.