Single-chamber double-stroke jar

Abstract

The present invention provides a single-chamber double-stroke jar, comprising a shell, wherein the shell comprises a driving chamber, a hydraulic chamber, an upper connecting short section, a stop chamber, a lower connecting short section, a lower balancing chamber, a locking device and a lower joint which are connected in sequence; a striking short section is installed in the hydraulic chamber, a spline core shaft is installed on the upper side of the striking short section, an upper stop core shaft is installed on the lower side of the striking short section, and a lower stop core shaft is installed on the lower side of the upper stop core shaft; the present invention adopts a rectangular spline drive combined with a wear-reducing belt design to increase the tool bearing capacity and guiding force, and prevent eccentric wear of the tool during drilling operations; a modular locking structure is designed, which is easy to unlock and reset, and can ensure that the jar can be used multiple times under complex well conditions, and the jar will not cause accidental shocks during drilling operations. The jar is safe and reliable, and has high shock efficiency, and whether to install a locking device can be selected according to needs.

Description

Technical Field

[0001] The invention relates to the technical field of drilling operations, and in particular to a single-cavity double-stroke jar. Background Art

[0002] The main structure of the hydraulic jar tool is composed of a drive shaft, a drive chamber, a hydraulic chamber, a knock nipple, a needle valve, a piston and a sealing assembly. It works by storing energy by holding the hydraulic oil under pressure for a certain period of time, and then instantly releasing the stored energy to generate a jarring force to achieve jamming.

[0003] Existing hydraulic jars can realize the jarring function, but there are basically the following problems in field use: 1. The downhole working conditions faced by the drilling jar are complex. The jar is easily affected by the tool string operation and causes mistaken downward jarring, affecting the normal drilling operation; 2. The temperature change downhole will affect the delay time of the jar, especially when the temperature rises, the viscosity of the hydraulic oil decreases, the hydraulic oil flow rate is too fast, resulting in a short pressure holding time, and the impact force generated by the jar is reduced; 3. The existing bidirectional jar is arranged in two independent pressure chambers, the double-chamber structure is more complicated, the reliability requirements are higher, and the installation and maintenance are troublesome; 4. The drilling jar is in the well for a long time, and the corners of inclined wells, horizontal wells, etc. are in contact with the jar and wear, which can easily cause eccentric wear of the tool and affect the service life of the tool. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a single-chamber dual-stroke jar, which is used to provide strong upward and downward impact force by lifting and pressing down when the downhole tool is stuck in drilling operations, so as to achieve the purpose of unblocking.

[0005] The present invention provides a single-chamber double-stroke jar, comprising a housing, wherein the housing comprises a driving chamber, a hydraulic chamber, an upper connecting nipple, a stop chamber, a lower connecting nipple, a lower balancing chamber, a locking device and a lower joint connected in sequence;

[0006] A knocking nipple is installed in the hydraulic cavity, a spline mandrel is installed on the upper side of the knocking nipple, an upper stop mandrel is installed on the lower side of the knocking nipple, and a lower stop mandrel is installed on the lower side of the upper stop mandrel;

[0007] The locking device comprises a locking chamber and a locking mandrel installed in the locking chamber, the upper end of the locking mandrel is connected to the lower stop mandrel, and the two ends of the locking chamber are respectively connected to the lower balancing chamber and the lower joint;

[0008] A locking groove is provided on the inner wall of the locking cavity, a disc spring is installed at the lower part of the locking groove, an upper locking limit ring is installed at the upper part of the locking groove, a locking block is installed between the disc spring and the upper locking limit ring, a locking protrusion adapted to the locking block is provided on the locking mandrel, and a lower locking limit ring is provided between the locking block and the disc spring;

[0009] The lower end of the spline core shaft is arranged in the driving chamber and the hydraulic chamber, and the upper end of the spline core shaft is located outside the driving chamber; the upper stop core shaft is arranged in the hydraulic chamber, the upper connecting short section and the stop chamber, and the lower stop core shaft is arranged in the stop chamber, the lower connecting short section and the lower balancing chamber; the locking core shaft is arranged in the lower balancing chamber, the locking chamber and the lower joint.

[0010] Preferably, the spline core shaft is provided with a friction-reducing belt and an outer rectangular spline, the inner wall of the drive cavity is provided with an inner rectangular spline, and the spline core shaft and the drive cavity transmit torque through the combination of the outer rectangular spline and the inner rectangular spline.

[0011] Preferably, a shock pad is provided between the hydraulic chamber and the spline core shaft, and the shock pad is provided on the upper side of the knocking nipple.

[0012] Preferably, two sealing rings are respectively arranged between the upper end of the upper connecting short section and the upper stopping core shaft, and between the lower end of the lower connecting short section and the lower stopping core shaft.

[0013] Preferably, a balancing piston is provided on the upper side of the upper connecting short section, and an upper stop chamber piston is provided on the lower side of the upper connecting short section. The balancing piston and the upper stop chamber piston are respectively mounted on the upper stop core shaft. An upper limit ring is installed at the lower end of the upper stop core shaft, and an upper stop ring is provided on the lower side of the upper limit ring.

[0014] Preferably, a lower stop chamber piston is provided on the upper side of the lower connecting short section, and a second balance piston is provided on the lower side of the lower connecting short section. The lower stop chamber piston and the second balance piston are respectively mounted on the lower stop core shaft. A lower limit ring is installed on the upper end of the lower stop core shaft, and a lower stop ring is provided on the upper side of the lower limit ring.

[0015] Preferably, a plurality of groups of oil grooves are respectively provided on the upper stop mandrel and the lower stop mandrel.

[0016] Preferably, an upper oil inlet hole and an upper oil outlet hole are formed at the upper end of the stop chamber, and a lower oil inlet hole and a lower oil outlet hole are formed at the lower end of the stop chamber.

[0017] Preferably, the stop chamber, the upper stop ring and the upper stop chamber piston form an upper high-pressure zone, and the stop chamber, the lower stop ring and the lower stop chamber piston form a lower high-pressure zone.

[0018] Preferably, the upper stop ring and the lower stop ring have the same structure, the lower stop ring comprises a valve body, a throttle needle is arranged in the valve body, and a throttle hole 1 and a throttle hole 2 are respectively formed at two ends of the throttle needle.

[0019] The beneficial effects of the present invention are:

[0020] The present invention discloses a single-cavity double-stroke jar, which adopts a rectangular spline drive combined with a wear-reducing belt design to increase the tool's bearing capacity and guiding force, and prevent eccentric wear of the tool during drilling operations; a modular locking structure is designed, which is easy to unlock and reset, and can ensure that the jar is used multiple times in complex well conditions. The jar will not cause accidental jarring during drilling operations, which is safe and reliable, with high jarring efficiency, and the locking device can be installed according to needs; the delay structure adopts a throttle valve with viscosity compensation to improve the problem of unstable jarring force of the jar at different temperatures; it can adapt to drilling operations with different downhole temperatures, and avoid the problem of reduced viscosity of hydraulic oil and excessively fast flow rate due to high temperature, which causes the pressure holding time to be too short and the jarring force to be too small; the single-cavity double-stroke structural design ensures the functions of up and down jarring, and at the same time, the simplified structure facilitates the installation and maintenance of the tool, which is also more convenient in use; the double-plating and double-seal design ensures that the tool service life is maximized, and the tool drilling operation time is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the spline core shaft, the drive cavity and the hydraulic cavity section in the present invention;

[0022] Figure 2 It is a schematic diagram of the structure of the hydraulic chamber, the upper connecting short section and the stop chamber section in the present invention;

[0023] Figure 3 It is a schematic diagram of the structure of the stop chamber, the lower connecting short section and the lower balancing chamber section in the present invention;

[0024] Figure 4 It is a schematic diagram of the structure of the lower balance chamber, the locking device and the lower joint section of the present invention;

[0025] Figure 5 It is an exploded view of the spline core shaft and the drive cavity structure in the present invention;

[0026] Figure 6 It is a diagram of the working principle of holding pressure in the present invention;

[0027] Figure 7 It is a schematic diagram of the downward striking operation structure in the present invention;

[0028] Figure 8 It is a schematic diagram of the throttle needle structure in the present invention;

[0029] Fig. 9 It is a schematic diagram of the structure of the locking device in the present invention;

[0030] Fig.10 It is a schematic diagram of the structure of the stop chamber in the present invention;

[0031] Fig.11 is a cross-sectional schematic diagram of the locking device in the present invention;

[0032] In the figure: 1-spline mandrel, 2-driving chamber, 3-hydraulic chamber, 4-shock pad, 5-knocking short section, 6-upper stop mandrel, 7-balance piston 1, 8-upper connecting short section, 9-upper stop chamber piston, 10-stop chamber, 11-upper limit ring, 12-upper stop ring, 13-lower stop ring, 14-lower limit ring, 15-lower stop mandrel, 16-lower stop chamber piston, 17-lower connecting short section, 18-balance piston 2, 19-lower balance chamber, 20-locking device, 21-lower joint;

[0033] 101-friction reducing belt, 102-external rectangular spline, 201-internal rectangular spline;

[0034] 1001-upper oil inlet hole, 1002-upper oil outlet hole, 1003-lower oil inlet hole, 1004-lower oil outlet hole, 1005-upper high pressure area, 1006-lower high pressure area;

[0035] 1301-valve body, 1302-throttle needle, 1303-throttle hole 1, 1304-throttle hole 2;

[0036] 2001-locking mandrel, 2002-locking chamber, 2003-upper locking limit ring, 2004-locking block, 2005-lower locking limit ring, 2006-disc spring. DETAILED DESCRIPTION

[0037] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0038] See also Figure 1-Figure 4 , the embodiment of the present invention discloses a single-chamber double-stroke jar, comprising a housing, the housing comprising a driving chamber 2, a hydraulic chamber 3, an upper connecting short section 8, a stop chamber 10, a lower connecting short section 17, a lower balancing chamber 19, a locking device 20 and a lower joint 21 connected in sequence;

[0039] A striking nipple 5 is installed in the hydraulic chamber 3 , a spline mandrel 1 is installed on the upper side of the striking nipple 5 , an upper stop mandrel 6 is installed on the lower side of the striking nipple 5 , and a lower stop mandrel 15 is installed on the lower side of the upper stop mandrel 6 .

[0040] like Figure 3 , Figure 4 , Fig. 9As shown, the locking device 20 includes a locking cavity 2002 and a locking spindle 2001 installed in the locking cavity 2002, the upper end of the locking spindle 2001 is connected to the lower stop spindle 15, and the two ends of the locking cavity 2002 are respectively connected to the lower balance cavity 19 and the lower joint 21; a locking groove is provided on the inner wall of the locking cavity 2002, a disc spring 2006 is installed at the lower part of the locking groove, an upper locking limit ring 2003 is installed at the upper part of the locking groove, a locking block 2004 is installed between the disc spring 2006 and the upper locking limit ring 2003, a locking protrusion adapted to the locking block 2004 is provided on the locking spindle 2001, and a lower locking limit ring 2005 is provided between the locking block 2004 and the disc spring 2006;

[0041] The disc spring 2006 is set with a pre-pressure of 20T. Only when the downward push force exceeds 20T will the jar be unlocked and started.

[0042] like Figure 4 , Fig.11 As shown, the locking device 20 can be installed as needed. When a safety lock is not needed, the lower connecting short section 17 can be directly connected to the lower joint 21.

[0043] like Figure 1-Figure 4 As shown, the lower end of the spline core shaft 1 is arranged in the driving chamber 2 and the hydraulic chamber 3, and the upper end of the spline core shaft 1 is located outside the driving chamber 2; the upper stop core shaft 6 is arranged in the hydraulic chamber 3, the upper connecting short section 8 and the stop chamber 10, and the lower stop core shaft 15 is arranged in the stop chamber 10, the lower connecting short section 17 and the lower balancing chamber 19; the locking core shaft 2001 is arranged in the lower balancing chamber 19, the locking chamber 2002 and the lower joint 21.

[0044] like Figure 5 As shown, the spline core shaft 1 is provided with a friction-reducing belt 101 and an outer rectangular spline 102, and the inner wall of the driving cavity 2 is provided with an inner rectangular spline 201. The spline core shaft 1 and the driving cavity 2 transmit torque through the combination of the outer rectangular spline 102 and the inner rectangular spline 201;

[0045] The rectangular spline has a large contact area, high load-bearing capacity, better centering performance and guiding performance, and is more suitable for transmitting torque while drilling with a hydraulic jar. The design of the friction-reducing belt 101 on the spline mandrel 1 can prevent eccentric wear during the use of the tool.

[0046] like Figure 1 , Figure 2 As shown, a shock pad 4 is arranged between the hydraulic chamber 3 and the spline core shaft 1 , and the shock pad 4 is arranged on the upper side of the striking nipple 5 .

[0047] like Figure 2 , Figure 3As shown, two sealing rings are respectively arranged between the upper end of the upper connecting short section 8 and the upper stop mandrel 6, and between the lower end of the lower connecting short section 17 and the lower stop mandrel 15; a balancing piston 17 is arranged on the upper side of the upper connecting short section 8, and an upper stop chamber piston 9 is arranged on the lower side of the upper connecting short section 8. The balancing piston 17 and the upper stop chamber piston 9 are respectively mounted on the upper stop mandrel 6, and an upper limit ring 11 and an upper stop ring 12 are installed on the lower end of the upper stop mandrel 6. A lower stop chamber piston 16 is arranged on the upper side of the lower connecting short section 17, and a balancing piston 2 18 is arranged on the lower side of the lower connecting short section 17. The lower stop chamber piston 16 and the balancing piston 2 18 are respectively mounted on the lower stop mandrel 15, and a lower stop ring 13 and a lower limit ring 14 are installed on the upper end of the lower stop mandrel 15.

[0048] like Figure 2 , Figure 3 , Fig.10 As shown, the upper stop mandrel 6 and the lower stop mandrel 15 are respectively provided with a plurality of oil grooves, the upper end of the stop chamber is provided with an upper oil inlet hole 1001 and an upper oil outlet hole 1002, and the lower end of the stop chamber is provided with a lower oil inlet hole 1003 and a lower oil outlet hole 1004;

[0049] The upper and lower groups of oil filling holes and oil outlet holes are used to fill the upper and lower high-pressure areas with oil respectively, ensuring the single-chamber oil filling effect. During use, the residual gas in the stop chamber 10 will be discharged from the oil filling and outlet holes, and the upper stop chamber piston 9 and the lower stop chamber piston 16 will move to both ends to fill the space left by the gas and avoid the vacuum area.

[0050] The upper high-pressure area 1005 is formed due to the pressure build-up between the upper stop core shaft 6 and the stop chamber 10. The stop chamber 10, the upper stop ring 12 and the upper stop chamber piston 9 form the upper high-pressure area 1005.

[0051] The lower high pressure area 1006 is formed due to the pressure between the lower stop core shaft 15 and the stop chamber 10. The stop chamber 10, the lower stop ring 13 and the lower stop chamber piston 16 form the lower high pressure area 1006.

[0052] Among them, when in the pressure holding state, the pressure ranges of the upper high pressure area 1005 and the lower high pressure area 1006 are both 75MPa-150MPa;

[0053] The single-chamber double-stroke design, the stop chamber 10 and the upper stop mandrel 6 and the lower stop mandrel 15 respectively form the upper striking work area and the lower striking work area, which simplifies the structure on the basis of ensuring the function of the jar, and is easy to install and maintain. The upper and lower reduced diameters of the stop chamber, that is, the pressure holding stroke area, adopt a double-layer coating process. Compared with the single-layer coating process, the tool life is longer when the interference fit is operated.

[0054] like Figure 3 , Figure 6 , Figure 8As shown, the upper stop ring 12 and the lower stop ring 13 have the same structure. The lower stop ring 13 includes a valve body 1301. A throttle needle 1302 is arranged in the valve body 1301. A throttle hole 1303 and a throttle hole 2 1304 are respectively opened at both ends of the throttle needle 1302.

[0055] A new throttle valve structure is selected, which is composed of multiple throttle holes in series. It has the function of filtering liquid and also has the function of viscosity compensation. When the temperature changes the viscosity of the hydraulic oil, the flow rate of the hydraulic oil will not be affected, ensuring the stability of the hydraulic system response time.

[0056] like Figure 1-Figure 4 , Figure 8 , Fig. 9 As shown, a single-chamber double-stroke jar disclosed in the present invention has a spline core shaft 1 connected to a striking nipple 5, then connected to an upper stop core shaft 6 and a lower stop core shaft 15, and finally connected to a locking core shaft 2001;

[0057] The outside of the spline core shaft 1 is a driving chamber 2, a double sealing ring is arranged between the end face of the driving chamber 2 and the spline core shaft 1, the driving chamber 2 is connected to the hydraulic chamber 3, a shock pad 4 is arranged inside the spline core shaft 1 and the hydraulic chamber 3, and a balancing piston 7 is arranged inside the upper stop core shaft 6 and the hydraulic chamber 3;

[0058] The hydraulic chamber 3 is connected to the upper connecting short section 8, the upper end of the upper connecting short section 8 is provided with a double sealing ring, and then connected to the stop chamber 10, an upper stop chamber piston 9, an upper limit ring 11 and an upper stop ring 12 are provided between the stop chamber 10 and the upper stop core shaft 6, and multiple groups of oil grooves are provided at the fixing position of the upper stop core shaft 6, the upper limit ring 11 and the upper stop ring 12; a lower stop ring 13, a lower limit ring 14 and a lower stop chamber piston 16 are provided between the stop chamber 10 and the lower stop core shaft 15, and multiple groups of oil grooves are provided at the fixing position of the lower stop core shaft 15, the lower stop ring 13 and the lower limit ring 14; two groups of throttle needles 1302 are provided inside the upper stop ring 12 and the lower stop ring 13, and an upper oil inlet hole 1001, an upper oil outlet hole 1002, a lower oil inlet hole 1003 and a lower oil outlet hole 1004 are provided on the stop chamber 10;

[0059] The stop chamber 10 is connected to the lower connecting short section 17, and a double sealing ring is provided at the lower end of the lower connecting short section 17, and then connected to the lower balancing chamber 19 and the locking chamber 2002. A balancing piston 2 18 is provided inside the lower balancing chamber 19 and the lower stopping core shaft 15, and multiple groups of locking blocks 2004 and disc springs 2006 are provided inside the locking chamber 2002 and the locking core shaft 2001. The locking chamber 2002 is connected to the lower joint 21.

[0060] like Figure 1-Figure 4 , Figure 5 , Fig. 9As shown, when the drilling is not used for jarring, the locking device 20 is in a locked state; the outer rectangular spline 102 and the inner rectangular spline 201 of the spline mandrel 1 and the drive cavity 2 transmit torque, and the outer rectangular spline 102 and the inner rectangular spline 201 can slide up and down during jarring;

[0061] When the jar strikes downward, it needs to be pushed down to unlock first, that is, the push-down tool pushes the spline spindle 1 downward, further pushes the connected striking nipple 5, the upper stop spindle 6 and the lower stop spindle 15 downward, and finally pushes the connected locking spindle 2001 downward;

[0062] The upper locking limit ring 2003 in the locking device 20 contacts the end face of the lower joint 21 of the lower balancing chamber 19, and the locking device 20 cannot move upward. Therefore, under the action of the thrust of the locking core shaft 2001 moving downward, the lower locking limit ring 2005 moves downward and compresses the disc spring 2006. At the same time, the downward tangential force pushes the locking block 2004 to move outward, and the locking core shaft 2001 continues to move downward. The locking block 2004 moves out of the groove on the locking core shaft 2001 and moves along the plane c on the surface of the locking core shaft 2001. From then on, the jar is unlocked.

[0063] like Figure 2 , Figure 3 , Figure 6-Figure 8 As shown, after unlocking, the tool is continued to be lowered, the lower stop ring 14 is fixed on the lower stop mandrel 15, and the lower stop ring 13 is installed between the top of the lower stop mandrel 15 and the lower stop ring 14. During the tool lowering process, the lower stop ring 13 passes through the lower reduction of the inner cavity of the stop cavity, and the lower stop ring 13 and the lower reduction inner wall a are interference fit;

[0064] During the lowering process, the friction force generated by the lower stop ring 13 and the lower reduced diameter inner wall a pushes the lower stop ring 13 and the top lower end surface b of the lower stop core shaft 15 to stick together. At this time, the hydraulic oil cannot pass through the oil groove on the surface of the lower stop core shaft 15, and can only pass through the throttle needle 1302 inside the lower stop ring 13. Because the throttle hole 1303 and the throttle hole 2 1304 inside the throttle needle 1302 cause the flow of the hydraulic oil to be very small, the pressure will be accumulated between the lower stop core shaft 15 and the stop chamber to form a lower high-pressure area 1006;

[0065] As the tool is continuously lowered, the pressure in the lower high-pressure area 1006 continues to increase until the lower stop ring 13 completely passes through the lower reduced diameter of the stop chamber, and the pressure energy in the lower high-pressure area 1006 is released instantly, achieving the downward striking operation;

[0066] During the downward striking operation, the upward friction force will push the upper stop ring 12 away from the lower top of the upper stop core shaft 6 and stick to the upper limit ring 11. The hydraulic oil can flow from the oil groove on the surface of the upper stop core shaft 6, so the upper high-pressure area 1005 will not be formed.

[0067] The upward striking process is the same as the downward striking principle.

[0068] After the jarring and unblocking operation is completed, the locking device 20 can be reset, locked, and then the drilling operation can be continued.

[0069] like Figure 4 , Fig. 9 As shown, the resetting principle of the downward shock operation is as follows (the resetting principle of the upward shock operation is the same): after the downward shock operation is completed, the tool is lifted, and the locking block 2004 in the locking device 20 moves downward and slides into the groove on the locking core shaft 2001. At this time, the lifting tool is obviously blocked, and then the tool is pushed down with a force of 10T (the pre-pressure of the disc spring 2006 is 20T). The tool cannot move, indicating that the tool locking is completed.

[0070] The present invention discloses a single-chamber double-stroke jar, which adopts a rectangular spline drive combined with a friction-reducing belt 101 design to increase the tool bearing capacity and guiding force, and prevent eccentric wear of the tool during drilling operation;

[0071] The modular locking structure is designed, which is easy to unlock and reset, and can ensure that the jar can be used multiple times in complex well conditions. The jar will not cause accidental jarring during drilling operations. It is safe and reliable, and has high jarring efficiency. Whether to install the locking device 20 can be selected according to needs;

[0072] The delay structure adopts a throttle valve with viscosity compensation to improve the problem of unstable jarring force at different temperatures; it can adapt to drilling operations at different downhole temperatures and avoid the problem of low viscosity of hydraulic oil and excessive flow rate due to high temperature, which leads to short holding time and small jarring force.

[0073] The single-cavity double-stroke structural design ensures the functions of up and down shock, and at the same time, the simplified structure facilitates the installation and maintenance of the tool, making it more convenient to use. The double-coating double-seal design ensures that the tool service life is maximized, effectively improving the tool's drilling operation time.

[0074] The above specific implementations do not constitute a limitation on the protection scope of the present disclosure. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A single-chamber double-stroke jar, characterized in that: The housing comprises a driving chamber, a hydraulic chamber, an upper connecting nipple, a stop chamber, a lower connecting nipple, a lower balancing chamber, a locking device and a lower joint which are connected in sequence; A knocking nipple is installed in the hydraulic cavity, a spline mandrel is installed on the upper side of the knocking nipple, an upper stop mandrel is installed on the lower side of the knocking nipple, and a lower stop mandrel is installed on the lower side of the upper stop mandrel; The locking device comprises a locking chamber and a locking mandrel installed in the locking chamber, the upper end of the locking mandrel is connected to the lower stop mandrel, and the two ends of the locking chamber are respectively connected to the lower balancing chamber and the lower joint; A locking groove is provided on the inner wall of the locking cavity, a disc spring is installed at the lower part of the locking groove, an upper locking limit ring is installed at the upper part of the locking groove, a locking block is installed between the disc spring and the upper locking limit ring, a locking protrusion adapted to the locking block is provided on the locking mandrel, and a lower locking limit ring is provided between the locking block and the disc spring; The lower end of the spline mandrel is arranged in the driving cavity and the hydraulic cavity, and the upper end of the spline mandrel is located outside the driving cavity; the upper stop mandrel is arranged in the hydraulic cavity, the upper connecting short section and the stop cavity, and the lower stop mandrel is arranged in the stop cavity, the lower connecting short section and the lower balancing cavity; the locking mandrel is arranged in the lower balancing cavity, the locking cavity and the lower joint; The spline mandrel is provided with a friction-reducing belt and an outer rectangular spline, the inner wall of the drive cavity is provided with an inner rectangular spline, and the spline mandrel and the drive cavity transmit torque through the combination of the outer rectangular spline and the inner rectangular spline; A shock pad is arranged between the hydraulic chamber and the spline core shaft, and the shock pad is arranged on the upper side of the knocking nipple; Two sealing rings are respectively arranged between the upper end of the upper connecting short section and the upper stop core shaft, and between the lower end of the lower connecting short section and the lower stop core shaft; A balancing piston 1 is arranged on the upper side of the upper connecting short section, and an upper stop chamber piston is arranged on the lower side of the upper connecting short section. The balancing piston 1 and the upper stop chamber piston are respectively mounted on the upper stop mandrel. An upper limit ring is installed on the lower end of the upper stop mandrel, and an upper stop ring is arranged on the lower side of the upper limit ring. A lower stop chamber piston is arranged on the upper side of the lower connecting short section, and a second balance piston is arranged on the lower side of the lower connecting short section. The lower stop chamber piston and the second balance piston are respectively mounted on the lower stop mandrel. A lower limit ring is installed on the upper end of the lower stop mandrel, and a lower stop ring is arranged on the upper side of the lower limit ring. The upper stop mandrel and the lower stop mandrel are respectively provided with a plurality of groups of oil grooves; An upper oil inlet hole and an upper oil outlet hole are formed at the upper end of the stop chamber, and a lower oil inlet hole and a lower oil outlet hole are formed at the lower end of the stop chamber.

2. The single-chamber double-stroke jar according to claim 1, characterized in that: The stop chamber, the upper stop ring and the upper stop chamber piston form an upper high-pressure zone, and the stop chamber, the lower stop ring and the lower stop chamber piston form a lower high-pressure zone.

3. The single-chamber double-stroke jar according to claim 1, characterized in that: The upper stop ring and the lower stop ring have the same structure. The lower stop ring comprises a valve body. A throttle needle is arranged in the valve body. A throttle hole 1 and a throttle hole 2 are respectively formed at two ends of the throttle needle.

Images