Disclosed combination impact tool generates optimized linear hammering and vibrational impacts. Flow of pressurized fluid through an upper section of the tool generates linear hammering impacts, and flow of pressurized fluid through a lower section of the tool generates vibrational impacts. Flow of pressurized fluid through the lower section induces an eccentric arm to rotate and cause vibrational impacts. While frequency of hammering impacts can be controlled by varying pressure of the fluid flowing through the upper section, the frequency and amplitude of vibrational impacts can be controlled by varying weight of the eccentric arm and by varying pressure of the fluid flowing through lower section. Disclosed tool is particularly useful in drilling in shale and in fishing operations in a well-bore.

Disclosed is a fluid hammer tool with two separate fluid hammers in separate sections of the tool. The tool includes an upper poppet valve assembly along one fluid flow path, and a lower poppet valve assembly along a separate outer flow path. Both fluid flow paths are fed from an upper sub and both exit through a lower sub. Both poppet valves include spring return mechanisms. Sealing of each poppet valve propagates an upstream shock wave. The lower poppet valve assembly encounters greater fluid flow and generates a larger shock wave. In the period when the upper poppet valve is closed, the lower poppet valve cannot open.

A downhole rotary seal assembly is provided that includes a primary rotary seal, a barrier seal, and a seal carrier. The seal carrier includes an inner surface, an outer surface, and a first groove dimensioned to receive the primary rotary seal at the inner surface. The seal carrier also includes a second groove dimensioned to receive the barrier seal at the inner surface. An aperture is defined on the inner surface between the first groove and the second groove. A relief port is positioned between the first groove and the second groove, the relief port being positioned to fluidly couple the aperture and the outer surface. A valve provided in the relief port. The valve includes a check valve having a predefined crack pressure.

A drill string section of a drill string for drilling in the ground having arranged on the outside of the drill string section at least one marking by means of which abrasion can be recognized.

A fluid operated drilling device for drilling a hole includes a hammer connected to a drill rod, and a rotation device to rotate the drill rod and the hammer. The hammer includes a tubular main body, a back head, a cylindrical piston housing, a reciprocating piston and a space between the piston. The piston housing is divided by an annular pressurizing portion into first and second space portions for elevating and striking the piston. First communication channels from a hollow portion of the piston into a second space between the piston and the main body discharge fluid between the piston and the main body. A method for drilling a hole using the fluid operated drilling device is also disclosed.

A rock drilling arrangement includes an impact device having a frame, pressure chambers in the frame, and a piston arranged in the impact device. The arrangement further includes a rear mounting arrangement for attaching the impact device to a carriage, a front mounting arrangement for attaching the impact device to a machine component, at least one fore pressure accumulator arranged on a front side of the rear mounting arrangement in an axial direction of the piston, and at least one rear pressure accumulator arranged on a back side of the rear mounting arrangement. The fore pressure accumulator and the rear pressure accumulator are connected to one of the pressure chambers and arranged to absorb pressure fluctuations in the pressure chambers.

A rock drilling arrangement includes an impact device having a frame, pressure chambers in the frame, and a piston arranged in the impact device. The arrangement further includes a rear mounting arrangement for attaching the impact device to a carriage, a front mounting arrangement for attaching the impact device to a machine component, at least one fore pressure accumulator arranged on a front side of the rear mounting arrangement in an axial direction of the piston, and at least one rear pressure accumulator arranged on a back side of the rear mounting arrangement. The fore pressure accumulator and the rear pressure accumulator are connected to one of the pressure chambers and arranged to absorb pressure fluctuations in the pressure chambers.

A drilling tool is disclosed. The two ends of the drilling tool are respectively connected with an upper drilling tool and a drill bit. The drilling tool includes an axial striking part, a torsional striking part, and an auxiliary part. Under the combined action of a spring and a high-pressure drilling fluid, the hammer of the axial striking part generates an axial striking force to strike the upper housing; and the pendulum of the torsional striking part generates a torsional striking force to strike the lower housing. The reversing switch and the center tube are plugged together to simultaneously reverse torsion and axial striking forces, respectively. The high-pressure drilling fluid pushes the hammer and the pendulum to generate axial and torsional striking forces, respectively, to effectively increase the ROP and reduce the stick-slip phenomenon. The drilling tool is stable and reliable in a complex and changeable downhole environment.

A drilling tool is disclosed. The two ends of the drilling tool are respectively connected with an upper drilling tool and a drill bit. The drilling tool includes an axial striking part, a torsional striking part, and an auxiliary part. Under the combined action of a spring and a high-pressure drilling fluid, the hammer of the axial striking part generates an axial striking force to strike the upper housing; and the pendulum of the torsional striking part generates a torsional striking force to strike the lower housing. The reversing switch and the center tube are plugged together to simultaneously reverse torsion and axial striking forces, respectively. The high-pressure drilling fluid pushes the hammer and the pendulum to generate axial and torsional striking forces, respectively, to effectively increase the ROP and reduce the stick-slip phenomenon. The drilling tool is stable and reliable in a complex and changeable downhole environment.

The present invention relates to a drill bit assembly for fluid-operated percussion drill tools comprising a percussion bit having a head portion and a bit retaining portion. Engagement means are provided on the head portion engageable with complementary engagement means on a drive ring whereby rotational drive from the drive ring may be transmitted to the percussion bit. The assembly also comprises bit retaining means adapted for engagement with the bit retaining portion of the percussion bit to retain the percussion bit in the drill bit assembly. Connection means on the drive ring are adapted for connecting the drive ring to a drive means of the fluid-operated percussion drill tool. According to a first aspect, the drive ring comprises a plurality of separable part-annular drive dog segments, wherein the bit retaining means are provided on at least two of the drive dog segments. According to a second aspect the head portion of the bit comprises a main body and a plurality of bit inserts engaged therewith, and wherein the engagement means is provided by the bit inserts.