QJ All-Mechanical Drilling-While-Drilling Shock Tool

I. Uses and Features

　　The QJ-type all-mechanical downhole vibration tool is a mechanical device used for in-hole vibration and key retrieval during drilling operations. It integrates both upward and downward vibration functions, enabling it to resolve downhole sticking and other drilling incidents that may occur during drilling. It is the preferred vibration tool for directional and deep-well drilling operations.
　　The QJ-type all-mechanical downhole shock tool is resistant to oils and acidic/alkaline fluids within the pH range of 6 to 12, making it suitable for drilling conditions in both marine and onshore environments (including, but not limited to, oil-based muds and saltwater cements). It can operate normally under conditions ranging from -20℃ to 180℃.
　　The QJ-type all-mechanical downhole vibration tool has the following notable features:
　　⑴ Because a fully mechanical structure is employed, changes in the quality of the hydraulic oil inside the cavity will not affect the impact performance.
　　⑵ During operation, the internal cavity does not generate high pressure, ensuring excellent sealing performance and significantly extending its service life.
　　⑶ Before entering the well, set the upper and lower impact tonnages. Once you start operating downhole, these settings will no longer change, ensuring a constant impact force.
　　⑷ Due to its unique structure, the impact tool transmits torque more accurately and is better suited for drilling inclined wells.

II. Structure and Working Principle

　　1. Product marking

　　2. Structure

　　The structure of the mechanical downhole shock tool is shown in Figure 1. The shock tool mainly consists of an upper connection, an upper control sleeve, a middle sleeve, a lower control sleeve, a splined sleeve, a sealing nut, a splined shaft, an extended operating shaft, an operating shaft, an operating sleeve, a friction liner, Spring Tube I, Spring Tube II, Spring Tube III, upper and lower adjusting sleeves, upper and lower spacer sleeves, upper and lower centralizing sleeves, and various seals.

Figure 1

　　3. Working Principle of the Upward Impact

　　Place the vibrator in the locked position, then lift the drill string. Under the action of the upper elastic sleeve assembly, the drill string stores energy and experiences a delay. As the running shaft moves upward and reaches the predetermined tonnage, the locking mechanism is released, allowing the running shaft to slide out and the impact surface to strike upward, generating an upward impact. By repeating this process, the tool can deliver another upward impact.

　　4. Working Principle of Downward Impact

　　Place the vibrator in the locked position, then press down on the drill string. Under the action of the lower elastic sleeve assembly, the drill string stores energy and undergoes a delay. As the running shaft moves downward and reaches the predetermined tonnage, the locking mechanism is released, allowing the running shaft to slide out. The impact surface then strikes downward, generating a downstroke. By repeating this process, the tool can deliver additional downstrokes.

III. Use and Operation

　　1. Preparations Before Entering the Well

　　1.1 After reassembly, all connecting threads shall be tightened to the specified torque values as listed in Table 1. The internal cavity shall be filled with L-HM32 anti-wear hydraulic oil. The impact tonnage can be adjusted according to the specific requirements of the well in which the equipment will be used, and must pass the required ground testing.

Table 1: Tightening Torque of QJ-Type All-Mechanical Drilling-While-Drilling Shock Tool

Unit/kN·m

　　1.2 The downhole vibrator must be in the locked position before entering the well.
　　1.3 The drill string configuration should position the impact tool in the tensioned portion of the drill string, slightly above its neutral point. To enhance the flexibility of the drill string and reduce bending stresses on the tools, a flexible joint must be connected to the lower part of the impact tool.
　　1.4 Recommended Drill String Assembly
　　(← Down) Drill collar (outer diameter no less than the outer diameter of the impact tool) + flexible joint + QJ-type all-mechanical downhole impact tool + weighted drill pipe (outer diameter no greater than the outer diameter of the impact tool) (Up →)

　　1.5 After the vibrator is connected to the upright post, remove the clamp and store it properly.

　　2. Operating Instructions

　　2. 1. When running the drill string downhole, first start the pump to circulate the drilling fluid, then slowly lower the string. Avoid directly dropping it all the way to the bottom of the well, which could cause “artificial jarring.” If you encounter a stuck pipe during the run-in process, you can activate the jar to apply upward jarring and free the pipe.

　　2.2 During normal drilling operations, the impact tool should be in the locked position and operate under tensile stress.

　　2.3 When a stuck drill pipe incident occurs and an upward impact is required, follow these steps:

　　2.3.1 Apply an upward tensile force G to the drill string to generate a jarring impact.

　　Calculation of tension G during upward impact operations:

　　The general method is to add the suspended weight of the drill string at the upper part of the impactor to the set upward impact tonnage. However, in reality, numerous factors influence this load. Taking into account the frictional resistance of the wellbore wall, mud resistance, pump-on effect, and the error in the weight indicator, the load can be calculated using the following formula:

　　 Directional well:

　　G = G1 - G2 + G3 + G4 + G5 + G6 - G7

　　G —— Upward Tension

　　G1——Original suspended weight (drilling tools in the well)

　　G2——Suspension weight of the drill string below the vibrator

　　G3——Ground-set upper impact tonnage

　　G4—Mud resistance (approximately 50% of the upward pulling force)

　　G5—Frictional Resistance (approximately 10–20% of the upward pulling force)

　　G6—refers to the error of the weighing scale.

　　G7—Pump-Opening Force (G7 = Pump Pressure × Pump-Opening Area; see Table 3 for the pump-opening area)

　　 Naoki:

　　Negligible resistance:

　　G = G1 - G2 + G3 + G4 + G5 + G6

　　2.3.2 Lower the drill string to bring the impact tool back to the “locked” position, applying a downward weight of approximately (G1 - G2 - G3 - G4 - G5 - G6) 3 to 5 tons. During this step, you can make a mark on the drill pipe at the wellhead; each upward impact stroke will confirm that the impact tool has returned to the “locked” position.

　　2.4 When a stuck drill pipe incident occurs and a down-the-hole impact is required, proceed as follows:

　　2.4.1 Apply a shock by pressing down on the drill string under pressure G.

　　Calculation of pressure G′ during downburst operations:

　　The general method is: G′ = Ground-set downforce + Mud resistance + Friction resistance + Weight indicator error.

　　2.4.2 Raise the drill string, applying an upward force of approximately G1 - G2 + G5 + G6 + (3–5) tons to return the shock absorber to its locked position.

IV. Maintenance and Servicing

　　 1. On-site maintenance and repair

　　When the impact duration is short or moderate and the number of impacts is relatively low, maintenance and repairs can be carried out on-site at the rig floor. After pulling the wellhead out at the drilling rig site, flush the outer surface of the impactor and the mud in the water ports, and also clean the oil-seal areas. Clean the chrome-plated surface of the spline shaft, dry it thoroughly, apply anti-rust oil, put on the clamp, and fit appropriate thread protectors onto both ends of the connector.

　　 2. Pipe station maintenance

　　After prolonged operation underground (after 500 hours of normal operation) or following severe shock loading, a major overhaul should be performed at the pipe station.

　　2.1 Before maintenance, the following equipment, tools, and accessories should be prepared:

　　⑴ Corresponding tools such as chain pliers, pipe wrenches, and adjustable wrenches that are suitable for the tool’s size.

　　⑵ Equipment such as cranes, dismantling and assembly racks, and test stands.

　　⑶ The special tools included with this product.

　　⑷ Kerosene and other cleaning agents.

　　⑸ Various required greases, lubricating oils, and L-HM32 anti-wear oil.

　　2.2 Disassembly of the vibrator:

　　Before disassembly, thoroughly clean the outer cylinder, water ports, oil plugs, and both large and small plugs of any accumulated silt and debris.

　　b Before removing the vibrator, it should be placed in the test stand for inspection and compared with the previous vibration load to facilitate maintenance and replacement of parts that have become excessively worn.

　　c. The vibrator must be in the locked position before it can be removed. If the vibrator is not in the locked position, it should be run on the test stand until it reaches the locked position.

　　d. Loosen the connecting threads on the outer cylinder on the disassembly stand.

　　e Use the jaws of the clamp to securely grip the upper control sleeve, then remove the upper connector.

　　f Use the terminal crimp cap removal/installation tool to remove the terminal crimp cap.

　　g. Insert the middle sleeve into the clamp and loosen the upper control sleeve. At this point, oil will begin to flow out of the sleeve; collect the hydraulic oil in a container (the hydraulic oil can be reused after sedimentation and filtration). The sealing piston will also come loose from the extended operating shaft and remain inside the upper control sleeve. Remove the upper control sleeve.

　　 Note: It’s best to remove the upper adjusting sleeve to avoid damaging the piston clip.

　　h. Insert the lower control sleeve into the clamp, release the middle sleeve, and remove the piston retaining ring (this retaining ring is not present on QJ 121). The retaining ring is seated on the extended operating shaft.

　　i Remove the elastic sleeve.

　　j Remove the locating sleeve from the running shaft.

　　k Remove the friction bushing and the spacer bushing.

　　l Reinstall the middle sleeve, the control sleeve, and the upper connector, and then attach the test connector. Place the splined shaft onto the test stand and pull it to its maximum extension. Next, remove the upper connector, then the control sleeve, and finally the middle sleeve. Lastly, remove the friction slips.

　　m Remove the locating sleeve.

　　n Remove the elastic sleeve.

　　o Clamp the spline sleeve in the vise, loosen the fastening nut, and remove the lower control sleeve.

　　p Loosen the lock nut.

　　Q: Clamp the splined sleeve to remove the connector, the running shaft, and the assembly consisting of the running shaft and its extension.

　　 Note: The extended running shaft, running shaft, and connector are tightened after applying anaerobic adhesive. Under normal circumstances, they should not be disassembled; they should only be disassembled when replacement of any of their components is necessary. When disassembling, the parts must be uniformly heated to between 260°C and 315°C, and then immediately taken apart.

　　Clamp the large end of the splined shaft, then remove the retaining ring and locknut.

　　S Pull out the splined shaft.

　　t Remove the lock nut from the splined shaft, and then straighten the sleeve and packing assembly.

　　u Remove the sealing piston from the upper control sleeve.

　　v Remove the upper and lower adjustment sleeves from the upper and lower control sleeves, respectively. The upper adjustment sleeve has a left-hand thread, while the lower adjustment sleeve has a right-hand thread.

　　w Remove all seals.

　　x Clean all components. Each time a component is disassembled, all sleeves, splines, male connectors, female connectors, and shoulder surfaces must be inspected using magnetic particle inspection or other non-destructive testing methods. Special attention should be paid to these areas; any parts found with cracks must be replaced.

　　 Attention: After disassembling all parts, arrange them in sequential order and be sure to keep detailed records. For rubber components, pay close attention to their installation positions and record this information for ease of future assembly. Do not mix these parts with those from other assemblies.

　　2.3 Assembly of the Vibrator

　　a. Inspect all loaded parts for non-destructive testing. Any burrs or scratches found must be repaired—especially at threaded connections, where burrs must be carefully removed using a combination file, oilstone, or sandpaper. Parts with cracks must be replaced immediately. Severely damaged parts that cannot be repaired should be replaced. Parts with cuts, notches, or scratches on sealing surfaces must be repaired; those that cannot be repaired must be replaced.

　　b It is recommended to replace all rubber seals, O-rings, and retaining rings.

　　c. Clean all parts thoroughly and inspect them carefully to ensure they are in good condition. After drying them completely, apply a thin layer of lubricant. Before assembly, apply thread-locking compound to all threaded connections.

　　d. Assemble all rubber parts onto the respective components.

　　e Clean the inner cavity of the spline sleeve, grind the inner sealing surface with fine sandpaper, apply a small amount of calcium-based grease to the sealing surface inside the spline cavity, and then insert two centering sleeves. Next, assemble the sealing device in sequence.

　　f. The tightened nut that has already been installed (Sealed nut) Mounted on a splined shaft.

　　 Note: Install the compression nut. (Sealed nut) At the splined shaft sleeve and the compression nut. (Sealed nut) A gap of 1.5 to 2 mm is left between the connecting threaded shoulder surfaces.

　　G. Clamp the large end of the splined shaft and install the splined sleeve assembly.

　　h Except for QJ108 and QJ121, all other specifications of impactors should be fitted with impact pads. (lower spacer) 。

　　I install the lock nut and anti-loosening retaining ring. (Carrier ring) 。

　　Install the connector, run the shaft, and extend the running shaft assembly. After confirming that the “O”-ring seal has been properly installed, apply anaerobic adhesive and then tighten the components together—there is no need to remove them—and connect them to the splined shaft. Tighten the locknut securely. Except for models QJ108 and QJ121, all other specifications of the impact wrenches are equipped with a bottom striking pad. (upper spacer) Grind down the clamp marks and apply a small amount of calcium-based grease to the shaft surface.

　　k. Insert friction bushings into the middle sleeve (for QJ108 and QJ121, install two friction spacer bushings), then insert the spacer bushings. If the spacer bushings have been replaced with new ones, they must be connected to the lower control sleeve. Before assembly, measure the clearance between the outer sleeve shoulder and the mating surface, and trim any excess dimension from the spacer bushings (i.e., the outer sleeve clearance dimension) before proceeding with assembly.

　　l Clamp the lower control sleeve, insert the lower adjustment sleeve, and confirm that the “O”-ring seal has been properly installed. Then, slide the lower adjustment sleeve all the way back to its maximum retracted position and rotate it upward by one full turn. Finally, connect this assembly to the splined sleeve.

　　Install three elastic sleeves onto the running shaft, making sure not to install them in the wrong direction.

　　n Install the positioning sleeve. Apply a small amount of calcium-based grease to the running shaft and the running sleeve. Install the friction pawl onto the running shaft and ensure it is properly aligned to the specified dimensions.

　　o Install the upper positioning sleeve and three elastic sleeves, paying attention to ensure that they are not installed in the wrong direction.

　　Clamp the lower control sleeve, install the middle sleeve assembly, and confirm that the friction bushings (two friction spacer bushings for QJ108 and QJ121) and spacer bushings have been properly installed into the middle sleeve.

　　Q: Install the piston retaining ring onto the extended drive shaft.

　　Insert the middle sleeve of the r clamp, then install the control sleeve. First, slide the upper adjustment assembly into the upper control sleeve, screw it in until it’s fully tightened, and then back off two clicks. Next, tighten the outer sleeve securely.

　　Assemble the balance piston. Then, use the special tool to install the balance piston onto the extended drive shaft.

　　Use a dedicated tool to install and tighten the terminal crimp cap.

　　u Clamp the upper control sleeve onto the fitting and tighten it securely.

　　v. After assembly, the impactor shall be tightly fastened to the outer cylinder using the torque specified in Table 1.

V. Ground Testing

　　1. Oil injection
　　1.1 Place the vibrator in a vise for support (do not clamp it tightly) or suspend it, as shown in Figure 2, so that the connector end of the vibrator is elevated.

Figure 2

　　1.2 Connect the fueling connector and the fueling hose to the fueling port on the splined sleeve, and slowly fill the vibrator with L-HM32 anti-wear hydraulic oil. Continue filling until the oil reaches the oil port on the upper control sleeve, then connect the return hose. Keep adding oil until no more air bubbles are present. Next, lower the upper end and raise the spindle section to seal off the gas discharge at the balance piston, and tighten the oil plug.
　　2. Sealing Test
　　After the vibrator is securely connected and lubricated, install sealing test fittings onto the threaded connections at both ends. Then, use a pressurizing pump to inject pressure into the vibrator’s water ports. The test pressure must be equal to or greater than 30 MPa; maintain this pressure for 5 minutes, during which the pressure drop should not exceed 0.5 MPa. The vibrator is considered qualified if no leakage is observed.
　　3. Impact Test
　　⑴ The impactor must be tightened to the recommended tightening torque specified in Table 1 before it can be used in the test stand.
　　⑵ When placing the vibrator into the test stand and adjusting the vibration tonnage, the adjustment hole should face upward.
　　⑶ Adjust the tonnage according to the direction shown in the attached diagram, proceeding gradually from lower to higher tonnages until the upper and lower impact forces specified in Table 2 are reached. Record these values in the designated record form. The factory may only ship the product after the impact forces have been properly adjusted according to the specifications in Table 2 and recorded in the form. After product maintenance, users may adjust the upper and lower impact force tonnages according to the requirements of each oilfield and region.
　　⑷ Install the oil filler plug, large plug, small plug, and retaining ring.

Table 2: Rated Impact Force and Factory-Tested Impact Force of the QJ-type All-Mechanical Drilling-While-Rigging Shock Absorber

Unit: kN

VI. Specification Series and Performance Parameters

　　The main performance parameters of the QJ-type all-mechanical downhole shock tool are shown in Table 3.

Table 3: Specification Series and Performance Parameters

7. Ordering Instructions

　　1. Please specify the required vibrator model and specifications.
　　2. For vibrators of the same model and specification, it is recommended to order several sets of spare seals and wear parts at the same time.
　　3. If you need to order steel parts, please provide the model and specifications of the vibrator, and specify the name and quantity.
　　4. Under reasonable storage conditions (sealed, moisture-proof, protected from sunlight, and kept at room temperature), the service life of rubber seals is 18 months.
　　5. If you need to order impact tools and equipment with special specifications and series, please provide your specific requirements.

8. Attached Figures