A wellbore drill bit assembly includes a drill bit that includes a drilling fluid pathway that has an inlet fluidly connected to a drilling fluid entrance of the drill bit and an outlet fluidly connected to a drilling fluid exit of the drill bit; and a nozzle positioned in the drilling fluid pathway, where at least a portion of the nozzle includes a removable material configured to dissolve or erode in contact with a drilling fluid additive.

A wellbore drill bit assembly includes a drill bit that includes a drilling fluid pathway that has an inlet fluidly connected to a drilling fluid entrance of the drill bit and an outlet fluidly connected to a drilling fluid exit of the drill bit; and a nozzle positioned in the drilling fluid pathway, where at least a portion of the nozzle includes a removable material configured to dissolve or erode in contact with a drilling fluid additive.

A rotary steerable drill string (16) employs a drill bit (10) selected to positively contribute to underpressure in a preselected azimuthal segment of the borehole relative to an opposing azimuthal section. Generally, a high flow velocity of drilling fluid in the selected azimuthal segment relative to in other segments will result in a more pronounced underpressure in the selected azimuthal segment. Drill bit designs which locally enhance the drilling fluid flow velocity are proposed to be employed in the present rotary steerable drill string.

A rotary steerable drill string (16) employs a drill bit (10) selected to positively contribute to underpressure in a preselected azimuthal segment of the borehole relative to an opposing azimuthal section. Generally, a high flow velocity of drilling fluid in the selected azimuthal segment relative to in other segments will result in a more pronounced underpressure in the selected azimuthal segment. Drill bit designs which locally enhance the drilling fluid flow velocity are proposed to be employed in the present rotary steerable drill string.

An example drill bit includes a body that is connectable to a drill string. The body has a base configured to face downhole within a wellbore and a perimeter configured to face a wall of the wellbore. The body includes a first nozzle and a second nozzle. The first nozzle corresponds to a first channel that exits the body through the perimeter and the second nozzle corresponds to a second channel that exits the body through the base. The example drill bit also includes a bit cutter on the base of the body and a valve within the body. The valve is configured to move within the body to block either the first channel or the second channel.

An example drill bit includes a body that is connectable to a drill string. The body has a base configured to face downhole within a wellbore and a perimeter configured to face a wall of the wellbore. The body includes a first nozzle and a second nozzle. The first nozzle corresponds to a first channel that exits the body through the perimeter and the second nozzle corresponds to a second channel that exits the body through the base. The example drill bit also includes a bit cutter on the base of the body and a valve within the body. The valve is configured to move within the body to block either the first channel or the second channel.

A downhole tool for conveyance within a tubular secured in a wellbore extending into a subterranean formation. The downhole tool includes a sealing material and a laser apparatus operable to cut a slot in the tubular. The downhole tool is operable to provide melted sealing material within the slot.

A hydro boring system includes a hydro boring head and a vacuum tube. The hydro boring head includes a fluid nozzle that is configured to dispense a fluid during a boring process. The vacuum tube is in fluid communication with the hydro boring head, and the hydro boring system is configured to pull air through the hydro boring head and the vacuum tube during the boring process. A method of installing underground pipe using a hydro boring system includes positioning a hydro boring head adjacent to a material to be bored. The method also includes boring the material by activating a fluid nozzle such that a fluid is dispensed against the material to be bored process and pulling air through the hydro boring head while boring.

A hydro boring system includes a hydro boring head and a vacuum tube. The hydro boring head includes a fluid nozzle that is configured to dispense a fluid during a boring process. The vacuum tube is in fluid communication with the hydro boring head, and the hydro boring system is configured to pull air through the hydro boring head and the vacuum tube during the boring process. A method of installing underground pipe using a hydro boring system includes positioning a hydro boring head adjacent to a material to be bored. The method also includes boring the material by activating a fluid nozzle such that a fluid is dispensed against the material to be bored process and pulling air through the hydro boring head while boring.

A cutting table comprises hard material, and a fluid flow pathway within the hard material. The fluid flow pathway is configured to direct fluid proximate outermost boundaries of the hard material through one or more regions of the hard material inward of the outermost boundary of the hard material. A cutting element and an earth-boring tool are also described.