A shank adapter, rock drilling machine and method of mounting a shank adapter of a rock drilling machine inside a slide bearing element. The shank adapter includes a coupling head and a rotation portion at its opposite ends, and a flushing portion located therebetween. Outer diameters of the coupling head and the rotation portion are both greater than outer diameters of portions of the shank adaptor located therebetween.

Provided are systems and methods for drilling a horizontally-oriented well having a sigmoid-shaped wellbore including an upper sigmoid portion having a downward curving wellbore trajectory and a lower sigmoid portion having an upward curving wellbore trajectory. The upper sigmoid portion having a first trajectory having a generally horizontal gradient at an entry point of the wellbore and that increases in downward gradient to a vertical gradient at an inflection point. The lower sigmoid portion having a second trajectory that includes the vertical gradient at the inflection point and that decreases in downward gradient to a generally horizontal gradient at a horizontal transition point of the wellbore.

Provided are systems and methods for drilling a horizontally-oriented well having a sigmoid-shaped wellbore including an upper sigmoid portion having a downward curving wellbore trajectory and a lower sigmoid portion having an upward curving wellbore trajectory. The upper sigmoid portion having a first trajectory having a generally horizontal gradient at an entry point of the wellbore and that increases in downward gradient to a vertical gradient at an inflection point. The lower sigmoid portion having a second trajectory that includes the vertical gradient at the inflection point and that decreases in downward gradient to a generally horizontal gradient at a horizontal transition point of the wellbore.

Provided are systems and methods for drilling a horizontally-oriented well having a sigmoid-shaped wellbore including an upper sigmoid portion having a downward curving wellbore trajectory and a lower sigmoid portion having an upward curving wellbore trajectory. The upper sigmoid portion having a first trajectory having a generally horizontal gradient at an entry point of the wellbore and that increases in downward gradient to a vertical gradient at an inflection point. The lower sigmoid portion having a second trajectory that includes the vertical gradient at the inflection point and that decreases in downward gradient to a generally horizontal gradient at a horizontal transition point of the wellbore.

Provided are systems and methods for drilling a horizontally-oriented well having a sigmoid-shaped wellbore including an upper sigmoid portion having a downward curving wellbore trajectory and a lower sigmoid portion having an upward curving wellbore trajectory. The upper sigmoid portion having a first trajectory having a generally horizontal gradient at an entry point of the wellbore and that increases in downward gradient to a vertical gradient at an inflection point. The lower sigmoid portion having a second trajectory that includes the vertical gradient at the inflection point and that decreases in downward gradient to a generally horizontal gradient at a horizontal transition point of the wellbore.

A hybrid bit includes an earth-boring element and a percussion element. The earth-boring element and the percussion element are coaxially arranged, with the earth-boring element surrounding the percussion element. A reciprocating member of the percussion element may oscillate in a manner that enables a bottom end of the reciprocating member to repeatedly protrude from a bottom end of the earth-boring element and to be repeatedly withdrawn. A configuration of the earth-boring element may enable it to drill into and remove some materials from an earth formation, while the percussion element may enable the hybrid bit to drill into and remove difficult-to-drill materials, including abrasive materials and/or materials with high compressive forces, such as chert.

The invention relates to a drilling device for earth or rock drilling having a mast, a drill drive with a drill drive shaft for driving a drill rod in a rotating manner, a drill drive carriage, which is supported in a movable manner along the mast and on which the drill drive is arranged, and an oscillation drive, which is designed for generating an oscillation, arranged behind the drill drive in a drilling direction and connected to the drill rod for transmitting an oscillation, wherein a rear connecting end of the drill drive shaft of the drill drive or the drill rod projects rearwards from the drill drive. According to the invention provision is made in that on the connecting end a rotary coupling with a first coupling piece, which is connected in an axially fixed and torque-proof manner to the connecting end of the drill drive shaft, and a second coupling piece, which is axially fixed and rotatable relative to the first coupling piece, is provided. Furthermore, provision is made in that the oscillation drive has a clamping means which is designed for releasably clamping the second coupling piece, wherein in the clamped state an axially fixed connection is formed between the oscillation drive and the second coupling piece.

A bottomhole assembly includes: a drill bit operable to vibrate when engaged with a formation and rotated; and a suspension sub including: a stator barrel for connection to a pipe string; a traveler barrel for connection to the drill bit; a slip joint longitudinally coupling the traveler barrel to the stator barrel while allowing movement of the traveler barrel between an extended position and a retracted position; a torsional joint connecting the traveler barrel to the stator barrel at and between the positions; and one or more springs disposed between the stator barrel and the traveler barrel. The suspension is tuned relative to the drill bit to: dampen the vibration of the drill bit when the BHA is rotated at a first angular velocity; and resonate the vibration of the drill bit when the BHA is rotated at a second angular velocity, thereby imparting percussive energy to the drill bit.

A bottomhole assembly includes: a drill bit operable to vibrate when engaged with a formation and rotated; and a suspension sub including: a stator barrel for connection to a pipe string; a traveler barrel for connection to the drill bit; a slip joint longitudinally coupling the traveler barrel to the stator barrel while allowing movement of the traveler barrel between an extended position and a retracted position; a torsional joint connecting the traveler barrel to the stator barrel at and between the positions; and one or more springs disposed between the stator barrel and the traveler barrel. The suspension is tuned relative to the drill bit to: dampen the vibration of the drill bit when the BHA is rotated at a first angular velocity; and resonate the vibration of the drill bit when the BHA is rotated at a second angular velocity, thereby imparting percussive energy to the drill bit.

A weight-on-bit self-adjusting drill bit includes a reaming bit, a WOB adjusting element, a transmission mechanism and a pilot bit and a pulsating impact generating mechanism; the pulsating impact generating mechanism includes a centralizing element, a driving element, a rotating element and a throttling element which are placed and connected successively, the centralizing element, the driving element and the rotating element are connected successively, the throttling element is in clearance fit with the rotating element, both of the centralizing element and the throttling element are respectively provided with a flow-through passage for the drilling fluid to flow through, the driving element drives the rotating element to rotate, the rotating element rotates relative to the flow-through passage on the throttling element.