An example drill bit is configured to operate within a wellbore of a hydrocarbon-bearing rock formation. The drill bit includes a drill bit body including at least one leg. The drill bit may include at least one roller cone rotatably mounted on the drill bit body. The roller cone includes a plurality of cutting elements for abrading or crushing rock. The drill bit includes at least one bearing mounted between a surface of the drill bit body and the at least one roller cone to facilitate rotation of the at least one roller cone. The drill bit system includes a lubrication system to reduce friction between moving parts of the drill bit. The drill bit system includes at least one wear sensor associated with the drill bit to sense physical wear on the drill bit.

Drill bit insert with a sintered cemented carbide body including a hard phase of tungsten carbide (WC) and a binder phase wherein the cemented carbide comprises 5.0-7.0 wt % Co, 0.10-0.35 wt % Cr, and a Cr/Co weight ratio of 0.015-0.058. The cemented carbide body has a hardness of 1520-1660 Hv30 and a toughness of K1.sub.c10.0 both measured in the bulk at the center of the longitudinal axis through the center of the insert, or 5 mm from any surface of the insert. The insert further has a surface toughness K1.sub.c12.0 measured at 0.5 mm below the surface of the body in a transverse direction to the longitudinal axis the insert. The invention also relates to a drill bit comprising the insert and the use of such a drill bit for drilling.

Drill bit insert with a sintered cemented carbide body including a hard phase of tungsten carbide (WC) and a binder phase wherein the cemented carbide comprises 5.0-7.0 wt % Co, 0.10-0.35 wt % Cr, and a Cr/Co weight ratio of 0.015-0.058. The cemented carbide body has a hardness of 1520-1660 Hv30 and a toughness of K1.sub.c10.0 both measured in the bulk at the center of the longitudinal axis through the center of the insert, or 5 mm from any surface of the insert. The insert further has a surface toughness K1.sub.c12.0 measured at 0.5 mm below the surface of the body in a transverse direction to the longitudinal axis the insert. The invention also relates to a drill bit comprising the insert and the use of such a drill bit for drilling.

A drilling rig has a bidirectional eccentric stabilizer for use in a wellbore. The bidirectional eccentric stabilizer is coupled between a drill string and a bottom hole assembly. The bidirectional eccentric stabilizer has a shaft connected between a first shaft end and a second shaft end, an annulus formed longitudinally through the shaft and a cutting portion formed on an outer surface of the shaft. The cutting portion has a first cutting portion, a second cutting portion, a plurality of helical blades, a plurality of flutes, a plurality of cutting nodes, and a plurality of impact arrestors. The bidirectional eccentric stabilizer has a center of eccentric rotation which is offset from the longitudinal axis of the shaft, enabling the bidirectional eccentric stabilizer to form a larger wellbore than a drill bit on the bottom hole assembly and a larger diameter wellbore than originally drilled by the drill bit.

A drilling rig has a bidirectional eccentric stabilizer for use in a wellbore. The bidirectional eccentric stabilizer is coupled between a drill string and a bottom hole assembly. The bidirectional eccentric stabilizer has a shaft connected between a first shaft end and a second shaft end, an annulus formed longitudinally through the shaft and a cutting portion formed on an outer surface of the shaft. The cutting portion has a first cutting portion, a second cutting portion, a plurality of helical blades, a plurality of flutes, a plurality of cutting nodes, and a plurality of impact arrestors. The bidirectional eccentric stabilizer has a center of eccentric rotation which is offset from the longitudinal axis of the shaft, enabling the bidirectional eccentric stabilizer to form a larger wellbore than a drill bit on the bottom hole assembly and a larger diameter wellbore than originally drilled by the drill bit.

An embodiment of a PCD insert comprises an embodiment of a PCD element joined to a cemented carbide substrate at an interface. The PCD element has internal diamond surfaces defining interstices between them. The PCD element comprises a masked or passivated region and an unmasked or unpassivated region, the unmasked or unpassivated region defining a boundary with the substrate, the boundary being the interface. At least some of the internal diamond surfaces of the masked or passivated region contact a mask or passivation medium, and some or all of the interstices of the masked or passivated region and of the unmasked or unpassivated region are at least partially filled with an infiltrant material.

An embodiment of a PCD insert comprises an embodiment of a PCD element joined to a cemented carbide substrate at an interface. The PCD element has internal diamond surfaces defining interstices between them. The PCD element comprises a masked or passivated region and an unmasked or unpassivated region, the unmasked or unpassivated region defining a boundary with the substrate, the boundary being the interface. At least some of the internal diamond surfaces of the masked or passivated region contact a mask or passivation medium, and some or all of the interstices of the masked or passivated region and of the unmasked or unpassivated region are at least partially filled with an infiltrant material.

A drilling system having retractable wings and method of using same. The system includes at least one wing, which can extend from the system once it engages in a casing and abuts against an abutment ring at the bottom end of the casing. When the system starts drilling a hole into the ground, the casing is installed down the hole. In one configuration, the at least one wing is at least partially retracted into the drilling system and locked in this position. In another configuration, the at least one wing extends from the drilling system and locks into an extended position. The system can be connected to a down-the-hole hammer, a top-hammer drilling rod, or any other suitable rock drilling tool/apparatus, and can be used with a single and a dual rotary drilling tool/apparatus.

A cutting element for a drill bit includes a PCD cutting face having a ridge that extends away from the periphery towards the center of the cutting face, terminating in a curved, central most ridge end. The cutting face further includes a surrounding surface consisting of the entire cutting face except for the ridge. The surrounding surface is free of flats and includes two side regions and a ramp region therebetween. The surrounding surface is continuously curved along a curved path that extends from the first side region to the ramp region to the other side region. In profile views, the surrounding surface may be linear moving from the top surface of the ridge to the periphery at every location along the curved path.

A concentric alignment device is provided that elevates the working face of a drill bit off of the inner wall of a casing or tubing to prevent premature wear of the working face of the drill bit. In horizontal drilling applications, the working face of a drill bit has a tendency to contact or rest on the inner wall of a casing or tubing, which negatively affects the working face of a drill bit. In some embodiments, one or more optional inserts are provided on the shank of a drill bit or on a centralizing sub such that the inserts contact the inner wall of a casing or tubing instead of the working face of the drill bit. In other embodiments, blade packages on a drill bit or sub contact the inner wall of a casing or tubing and also pump drilling fluid in a downhole direction.