The present invention relates to a combined crushing super-variable-diameter drill bit for natural gas hydrate exploitation, including a joint, an outer cylinder connected to the joint by thread, a nozzle I mounted in the outer cylinder, a mechanical locking mechanism, a blade telescoping mechanism, an end cap connected to the outer cylinder by thread, a seal ring IV mounted to the end cap, and a nozzle II mounted in the end cap by threaded connection. The present invention achieves integrated operation of conventional drilling and draw-back expanding, which can effectively solve the problems that the existing hydrate drill bit cannot drill a large borehole, cannot mechanically lock an extending position of the blade to stabilize the size of the borehole, and a single crushing method is inefficient.

The present invention relates to a combined crushing super-variable-diameter drill bit for natural gas hydrate exploitation, including a joint, an outer cylinder connected to the joint by thread, a nozzle I mounted in the outer cylinder, a mechanical locking mechanism, a blade telescoping mechanism, an end cap connected to the outer cylinder by thread, a seal ring IV mounted to the end cap, and a nozzle II mounted in the end cap by threaded connection. The present invention achieves integrated operation of conventional drilling and draw-back expanding, which can effectively solve the problems that the existing hydrate drill bit cannot drill a large borehole, cannot mechanically lock an extending position of the blade to stabilize the size of the borehole, and a single crushing method is inefficient.

A hybrid bit with roller cones having inserts is disclosed, includes a bit body, blades and roller cones. All the fixed cutting elements at the inner cone section, nose section and shoulder section of blades herein constitutes two sets of corresponding fixed cutting elements respectively, forming two profile envelopes of fixed cutting elements at least in the interval at the nose section and shoulder section, the two profile envelopes of fixed cutting elements are spaced at high and low intervals at the nose section and shoulder section, forming two stages of cutting by fixed cutting elements; and the cutting position of the cone insert mainly corresponds to the nose section and shoulder section of blades, the outermost cutting profile envelope of cone inserts formed by all or part of cutting elements on cones herein is higher than the outermost cutting profile envelope of fixed cutting elements, forming the third stage of cutting. The invention can effectively develop rate of penetration in hard and plastic formation, maintain and prolong the service life of the hybrid bit, and broaden the formation suitability of the hybrid bit.

A hybrid bit with roller cones having inserts is disclosed, includes a bit body, blades and roller cones. All the fixed cutting elements at the inner cone section, nose section and shoulder section of blades herein constitutes two sets of corresponding fixed cutting elements respectively, forming two profile envelopes of fixed cutting elements at least in the interval at the nose section and shoulder section, the two profile envelopes of fixed cutting elements are spaced at high and low intervals at the nose section and shoulder section, forming two stages of cutting by fixed cutting elements; and the cutting position of the cone insert mainly corresponds to the nose section and shoulder section of blades, the outermost cutting profile envelope of cone inserts formed by all or part of cutting elements on cones herein is higher than the outermost cutting profile envelope of fixed cutting elements, forming the third stage of cutting. The invention can effectively develop rate of penetration in hard and plastic formation, maintain and prolong the service life of the hybrid bit, and broaden the formation suitability of the hybrid bit.

Systems and methods for drilling a subterranean well with a drill bit include a drill bit body with a central bore. A plurality of ports extend through the nose end of the drill bit body from the central bore to an outside of the drill bit body. A blocked nozzle is located within one of the plurality of ports. The blocked nozzle has a nozzle bore end and a nozzle nose end opposite the nozzle bore end. A bore end disk is located at the nozzle bore end of the blocked nozzle, preventing a flow of fluids through the blocked nozzle past the bore end disk. A nose end disk is located at the nozzle nose end of the blocked nozzle, preventing the flow of fluids through the blocked nozzle past the nose end disk. The nose end disk and the bore end disk are removable.

Systems and methods for drilling a subterranean well with a drill bit include a drill bit body with a central bore. A plurality of ports extend through the nose end of the drill bit body from the central bore to an outside of the drill bit body. A blocked nozzle is located within one of the plurality of ports. The blocked nozzle has a nozzle bore end and a nozzle nose end opposite the nozzle bore end. A bore end disk is located at the nozzle bore end of the blocked nozzle, preventing a flow of fluids through the blocked nozzle past the bore end disk. A nose end disk is located at the nozzle nose end of the blocked nozzle, preventing the flow of fluids through the blocked nozzle past the nose end disk. The nose end disk and the bore end disk are removable.

An earth-boring tool may include at least one blade including a shoulder region and a face. A plurality of cutting elements may be arranged on the face of the blade and at least one cutting element may be positioned in the shoulder region such that a cutting face of the at least one cutting element is spaced a distance behind the face of the blade. A recessed portion of the blade may extend under at least one of the plurality of cutting elements arranged on the face of the blade and extending to the at least one cutting element positioned in the shoulder region.

An earth-boring tool may include at least one blade including a shoulder region and a face. A plurality of cutting elements may be arranged on the face of the blade and at least one cutting element may be positioned in the shoulder region such that a cutting face of the at least one cutting element is spaced a distance behind the face of the blade. A recessed portion of the blade may extend under at least one of the plurality of cutting elements arranged on the face of the blade and extending to the at least one cutting element positioned in the shoulder region.

A wellbore assembly includes a drill string and a drill bit in fluid communication with the drill string. The drill bit has a tubular wall, an internal fluid channel, a tapered tube, and a spring. The fluid channel receives and flows the drilling fluid from the drill bit bore and out the drill bit. The fluid channel includes an inwardly projecting shoulder. The tapered tube is disposed inside the fluid channel. The tube has a rim and a wall extending from and converging away from the rim in a flow direction of the drilling fluid. The spring is disposed between the inwardly projecting shoulder and the rim. The tapered tube is movable under fluidic pressure in the flow direction to compress or extend the spring. The tube pushes an obstruction in the fluid channel out of the fluid channel upon movement of the tube.

A wellbore assembly includes a drill string and a drill bit in fluid communication with the drill string. The drill bit has a tubular wall, an internal fluid channel, a tapered tube, and a spring. The fluid channel receives and flows the drilling fluid from the drill bit bore and out the drill bit. The fluid channel includes an inwardly projecting shoulder. The tapered tube is disposed inside the fluid channel. The tube has a rim and a wall extending from and converging away from the rim in a flow direction of the drilling fluid. The spring is disposed between the inwardly projecting shoulder and the rim. The tapered tube is movable under fluidic pressure in the flow direction to compress or extend the spring. The tube pushes an obstruction in the fluid channel out of the fluid channel upon movement of the tube.