A torque-adaptive impact tool suitable for a PDC (Polycrystalline Diamond Compact) bit is provided, which includes a PDC bit, a rotary-driving power device, and a torque-adaptive impact tool above the PDC bit. The torque-adaptive impact tool is located between the PDC bit and the rotary-driving power device, includes an outer housing, an upper end cover, a main shaft, an elastic element, an upper impact body, and a lower impact body. In a case of a normal operation of the bit, the tool does not impact the bit, but rotates along with the rotary-driving power device for drilling. In a case that a rock-breaking torque required by the bit exceeds a driving torque, the tool impact the bit.

The invention discloses a set of valves that impart hydraulic pressure pulses at specific frequencies that provide oscillatory movement of a shuttle valve within a of a downhole tool operations. These vibrations can lead to pulses for vertical seismic profiling of formations drilled, to check the location of the bit, or to detect the presence of abnormal pore pressure ahead of the bit. The pressure pulses can also be used to enhance drilling and production of wells.

The invention discloses a set of valves that impart hydraulic pressure pulses at specific frequencies that provide oscillatory movement of a shuttle valve within a of a downhole tool operations. These vibrations can lead to pulses for vertical seismic profiling of formations drilled, to check the location of the bit, or to detect the presence of abnormal pore pressure ahead of the bit. The pressure pulses can also be used to enhance drilling and production of wells.

A drilling tool has an upstream drilling string, a downstream drilling bit, and a percussive device connected between the upstream drilling string and the downstream drilling bit. In a first state, the upstream drilling string is generated with elastic compression by the percussive device, and in a second state, the upstream drilling string releases the elastic compression to apply impacts on the downstream drilling bit through the percussive device. The drilling tool has a prolonged service life and can effectively reduce the drilling cost.

A drilling tool has an upstream drilling string, a downstream drilling bit, and a percussive device connected between the upstream drilling string and the downstream drilling bit. In a first state, the upstream drilling string is generated with elastic compression by the percussive device, and in a second state, the upstream drilling string releases the elastic compression to apply impacts on the downstream drilling bit through the percussive device. The drilling tool has a prolonged service life and can effectively reduce the drilling cost.

An apparatus for controlling lateral movement of a laterally translating component includes a first fixed housing that remains in a fixed position with respect to a central axis and a second housing interfaced with the laterally translating component that moves linearly along the central axis. The first fixed housing and the second housing together define a first fluid chamber and a second fluid chamber for containing fluid interconnected by a fluid channel. The second housing moves linearly between a first position along the central axis that defines a first size for the first fluid chamber and the second fluid chamber and a second position along the central axis that defines a second size for the first fluid chamber and the second fluid chamber to control flow of the fluid through the channel. The first size is larger than the second size. The second position of the second housing limits lateral movement of the second housing and the interfaced laterally translating component to a greater degree than the first position of the second housing limits the lateral movement of the second housing and the interfaced laterally translating component.

An apparatus for controlling lateral movement of a laterally translating component includes a first fixed housing that remains in a fixed position with respect to a central axis and a second housing interfaced with the laterally translating component that moves linearly along the central axis. The first fixed housing and the second housing together define a first fluid chamber and a second fluid chamber for containing fluid interconnected by a fluid channel. The second housing moves linearly between a first position along the central axis that defines a first size for the first fluid chamber and the second fluid chamber and a second position along the central axis that defines a second size for the first fluid chamber and the second fluid chamber to control flow of the fluid through the channel. The first size is larger than the second size. The second position of the second housing limits lateral movement of the second housing and the interfaced laterally translating component to a greater degree than the first position of the second housing limits the lateral movement of the second housing and the interfaced laterally translating component.

An apparatus for boring a wellbore, including a bit body having a first end, an inner cavity, and a second end. The first end is connected to a workstring that is configured to deliver a rotational force to the bit body. The inner cavity contains a profile having a first radial cam surface. The second end includes a working face containing a cutting member. The apparatus also includes a pilot bit rotatively connected within the inner cavity. A second radial cam surface is contained on a first end of the pilot bit. The first and second radial cam surfaces are operatively configured to deliver a hammering force. A second end of the pilot bit may include an engaging surface configured to engage a formation surrounding the wellbore. The bit body rotates relative to the pilot bit.

An apparatus for boring a wellbore, including a bit body having a first end, an inner cavity, and a second end. The first end is connected to a workstring that is configured to deliver a rotational force to the bit body. The inner cavity contains a profile having a first radial cam surface. The second end includes a working face containing a cutting member. The apparatus also includes a pilot bit rotatively connected within the inner cavity. A second radial cam surface is contained on a first end of the pilot bit. The first and second radial cam surfaces are operatively configured to deliver a hammering force. A second end of the pilot bit may include an engaging surface configured to engage a formation surrounding the wellbore. The bit body rotates relative to the pilot bit.

A downhole apparatus connected to a workstring within a wellbore. The workstring is connected to a bit member. The apparatus includes a mandrel operatively connected to a downhole motor mechanism, an anvil member operatively formed on the bit member, the anvil member being operatively connected to the mandrel, a radial bearing housing unit operatively connected to the workstring, with the radial bearing housing unit being disposed about the mandrel, and a hammer member slidably attached to the radial bearing housing unit.