CN115874942A - Underground composite impact tool - Google Patents

Abstract

The invention provides a downhole composite impact tool comprising: a housing; the power main shaft is provided with a first central flow passage, and the inner wall of the power main shaft is provided with a spiral spline groove; the output main shaft is used for connecting a drill bit and is provided with a second central flow passage, and the outer wall of the output main shaft is provided with a spiral spline; the cam mechanism comprises a cam fixedly sleeved on the output main shaft and a driven piece positioned at the upper end of the cam, the upper end of the cam is a continuous cam surface, the lower end of the driven piece is a plane and is provided with a plurality of rollers which are uniformly distributed in the circumferential direction, and the rollers are in adaptive contact with the cam surface; the power main shaft can drive the output main shaft to rotate, the driven part can reciprocate along the axial direction under the action of the cam and jack up the upper drill stem connected with the shell, so that the upper drill stem and the output main shaft can form axial and circumferential composite impact on the spiral spline through the spiral spline under the action of bit pressure after moving to the highest point, and the composite impact is transmitted to the drill bit.

Description

Underground composite impact tool

Technical Field

The invention belongs to the technical field of oil and gas drilling engineering, and particularly relates to an underground composite impact tool.

Background

Along with the development of oil exploration and development, the proportion of complex wells such as deep wells, horizontal wells and the like is gradually increased, and the speed increase of drilling faces a new challenge. Drilling acceleration technology is an important topic in oil and gas well engineering. The existing drilling mode mainly realizes rock breaking by shearing and impacting the rock through the rotation of a drill bit. When drilling in hard stratum, the drill bit is easy to generate the phenomenon of drill-out, and further needs to drill at low rotating speed and low drilling pressure, which seriously restricts the mechanical drilling speed. The existing PDC drill bit mainly breaks the stratum in a cutting, shearing and extruding mode, and in the drilling process, the insufficient rock breaking energy and the stick-slip vibration are important reasons causing low mechanical drilling speed. When a PDC drill bit is drilled in a hard stratum or the penetration depth of the drill bit is too large, the drill bit stops rotating instantly due to insufficient rock breaking energy, and then the drill bit periodically generates stick-slip vibration, so that the service life of the drill bit is damaged, and the mechanical drilling speed is seriously influenced.

The PDC drill bit is used for effectively improving the mechanical rotating speed of the PDC drill bit and inhibiting stick-slip vibration of the drill bit. In the prior art, a composite impact drilling tool is adopted in a common mode, the tool consists of an axial impact unit and a torsional impact unit, and an axial impact hammer in the axial impact unit transmits impact energy to a PDC drill bit after completing a forward stroke so as to increase the cutting depth. However, when the axial impact hammer enters a reverse stroke, the generated impact power of the existing composite impact drilling tool easily causes the longitudinal vibration of the bottom of the drilling tool, so that the problems of low mechanical drilling efficiency, short service life of the tool and the like are caused, and the speed increasing effect in hard and hard strata difficult to drill is limited. In addition, the existing drilling speed-up tool has the defects of high failure rate, short service life and poor reliability.

Disclosure of Invention

In view of the above technical problems, the present invention is directed to a downhole composite impact tool, which can generate axial and circumferential composite impact forces on a drill bit, and can generate pressure pulses to act on the drill bit to form further axial impact on the drill bit, and in addition, the downhole composite impact tool can adapt to downhole conditions to automatically adjust to reduce soil-holding depth when the torque of the drill bit is too large, so as to effectively prevent a downhole motor from generating a stagnation phenomenon.

To this end, according to the present invention there is provided a downhole composite impact tool comprising: a housing configured in a cylindrical shape; the power main shaft is concentrically arranged in the shell and can rotate relative to the shell, the power main shaft is provided with a first central flow passage, and the inner wall surface of the power main shaft is provided with a spiral key groove extending along the axial part; the output main shaft is used for connecting a drill bit and is provided with a second central flow passage, and the outer wall surface of the output main shaft is provided with a spiral spline which can be matched with the spiral spline groove; the cam mechanism comprises a cam fixedly sleeved on the output main shaft and a driven piece positioned at the upper end of the cam, the upper end of the cam is constructed into a continuous cam surface, the lower end of the driven piece is constructed into a plane and is provided with a plurality of rollers which are uniformly distributed in the circumferential direction, and the rollers are in adaptive contact with the cam surface; the power main shaft can drive the output main shaft to rotate, the driven part can reciprocate axially under the action of the cam and jack up an upper drill string connected with the shell, and after the upper drill string and the output main shaft move to the highest point of travel, the upper drill string and the output main shaft can form axial and circumferential compound impact on the spiral spline through the spiral spline groove under the action of bit pressure and transmit the combined impact to a drill bit.

In one embodiment, a limiting step with a downward end face is formed on the inner wall of the shell, and the upper end face of the driven member can jack up an upper drill string connected with the shell through the limiting step.

In one embodiment, the pitch of the helical spline is set to be in the range of 100-800mm, and the helix angle of the helix formed by the helical extension of the helical spline is in the range of 5-85 degrees.

In one embodiment, the helical splines are provided with a width in the range of 40-200mm and a depth in the range of 5-20 mm.

In one embodiment, a first eccentric hole communicated with the first central channel is arranged in the power main shaft, the first eccentric hole is positioned at the axial inner end of the spiral spline groove, a second eccentric hole communicated with the second central flow channel is arranged at the upper end of the output main shaft, and the first eccentric hole and the second eccentric through hole can form throttling when being overlapped, so that pressure pulse is generated.

In one embodiment, an axially outer end of the first eccentric bore is formed as a first axial impact surface, an upper end surface of the output spindle is formed as a second axial impact surface, and a maximum distance D between the first axial impact surface and the second axial impact surface is smaller than an axial movement stroke H of the driven member.

In one embodiment, an annular limiting groove is formed in the outer surface of the output main shaft, a through hole is formed in the side wall of the power main shaft, a falling-prevention pin block is installed in the through hole, the axial inner end of the falling-prevention pin block extends into the annular limiting groove,

the axial width of the annular limiting groove is larger than the width of the anti-falling pin block.

In one embodiment, the housing is configured to include an upper shell, a middle joint, and a lower shell fixedly connected in sequence from top to bottom.

In one embodiment, a bearing string is sleeved on the power main shaft, the bearing string is located between the upper shell and the power main shaft, and a first upper centering wear-resistant assembly and a second upper centering wear-resistant assembly are respectively arranged at two ends of the bearing string.

In one embodiment, a limiting cylinder is fixedly connected to the lower end of the lower shell, and a lower centering wear-resistant assembly is arranged between the limiting cylinder and the output spindle.

Compared with the prior art, the method has the advantages that:

according to the underground composite impact tool, the power main shaft can be driven by the cam mechanism to drive the upper drill column to axially move, and the spiral spline is subjected to axial and circumferential composite impact through the spiral spline key groove, so that axial and circumferential composite impact force is generated on a drill bit. And the underground composite impact tool can generate pressure pulse and act on the output main shaft, so that further axial impact is formed on the drill bit, the drill bit impact force is enhanced, and the drill bit drilling construction is improved. In addition, when the drill bit moment of torsion was too big, the output main shaft can adapt to the operating mode in the pit and carry out automatically regulated, and it can upwards screw in for the power main shaft under the mating action of helical spline and helical spline groove to reduce the drill bit soil depth, realize reducing the drill bit moment of torsion, this can effectively prevent that the motor in the pit from producing the hysteresis. These are all very favorable to improving the downhole working property of compound percussion tool in the pit, have improved and bored the efficiency of construction greatly, have strengthened and bored the construction effect apparently. In addition, the underground composite impact tool is convenient to operate, can adapt to the underground actual working condition in the working process, is automatically adjusted, and has strong adaptability.

Drawings

The present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the structure of a downhole composite stroker tool according to the present invention.

Fig. 2 schematically shows the configuration of the helical splines on the output spindle.

Fig. 3 schematically shows the structure of the helical spline grooves on the power spindle.

Fig. 4 schematically shows the distribution structure of the first eccentric holes on the power main shaft and the second eccentric holes on the output main shaft.

Fig. 5 schematically shows the structure of the cam.

Fig. 6 schematically shows a developed configuration of the cam surface of the cam shown in fig. 5.

Fig. 7 schematically shows the structure of the follower.

In the present application, the drawings are schematic, merely illustrative of the principles of the invention, and are not drawn to scale.

Detailed Description

The invention is described below with reference to the accompanying drawings.

In this application, it is noted that the end of the downhole composite stroker tool lowered into the wellbore near the wellhead is defined as the upper end or similar term, and the end away from the wellhead is defined as the lower end or similar term.

In addition, directional terms or qualifiers "upper" and "lower" used in the present application refer to fig. 1 as a reference. They are not intended to limit the absolute positions of the parts involved, but may vary from case to case.

FIG. 1 shows the structure of a downhole composite stroker tool 100 according to the present invention. As shown in fig. 1, a downhole composite impact tool 100 comprises a housing 1, a power spindle 2 concentrically arranged within the housing 1, and an output spindle 4 for connection to a drill bit. The power main shaft 2 is concentrically arranged inside the housing 1, and a first central flow passage 21 extending along the axial direction is arranged in the power main shaft 2 and used for flowing through drilling fluid. The power main shaft 2 is sleeved with a bearing string 3, and the power main shaft 2 is rotationally connected with the shell 1 through the bearing string 3. The output spindle 4 is arranged concentrically in the housing 1 and is arranged at the lower end of the power spindle 2, the output spindle 4 being provided with a second central flow channel 41 extending in the axial direction.

According to the present invention, as shown in fig. 1, a spiral spline groove 22 extending in an axial direction is provided on an inner wall surface of the power spindle 2. Meanwhile, the outer wall surface of the output spindle 4 is provided with a helical spline 42 which can be matched with the helical spline groove 22. The power main shaft 2 and the driven main shaft 4 can form a fit connection by matching the spiral spline groove 22 with the spiral spline 42, and the driven main shaft 4 can be screwed in or out relative to the power main shaft 2, so that relative axial movement and relative rotation of the two are realized. Accordingly, on the one hand, the power spindle 2 and the output spindle 4 can transmit torque through the helical spline 42 and the helical spline groove 22, and on the other hand, the output spindle 4 can move upward or downward with respect to the power spindle 2 by the action of the helical spline 42 and the helical spline groove 22.

As shown in fig. 1, a cam mechanism 5 is fitted over the output spindle 4. The cam mechanism 5 comprises a cam 51 fixedly sleeved on the output spindle 4 and a follower 52 arranged at the upper end of the cam 51, wherein the upper end of the cam 51 is configured into a continuous cam surface 511, the lower end of the follower 52 is configured into a plane, a plurality of rollers 53 uniformly distributed in the circumferential direction are arranged at the lower end of the follower 52, and the rollers 53 are in fit contact with the cam surface 511.

In practice, the downhole composite stroker tool 100 is mounted at the lower end of a downhole power motor (not shown). In operation, the downhole power motor drives the power spindle 2 to rotate, and the power spindle 2 is configured to rotate the output spindle 4 to transfer power from the downhole power motor to the drill bit. Because the cam 51 is fixedly sleeved on the output main shaft 4, the output main shaft 4 drives the cam 51 to rotate in the rotating process, the driven member 52 can reciprocate axially under the matching action of the roller 53 and the cam surface 511 of the cam 51 and jack up an upper drill string (not shown) connected with the shell 1, so that the upper drill string and the output main shaft 4 can form axial and circumferential composite impact on the spiral spline 42 through the spiral spline groove 22 under the action of bit pressure after moving to the highest point, and the composite impact is transmitted to a drill bit.

In the embodiment, when the torque of the drill bit is too large, the output spindle 4 can also be screwed upwards relative to the power spindle 2 under the matching action of the spiral spline groove 22 and the spiral spline 42 to absorb a certain torque, so that the output spindle 4 moves upwards relative to the power spindle 2, the soil depth of the drill bit is reduced, and the phenomenon of stagnation of a downhole motor can be effectively prevented.

According to the present invention, as shown in fig. 1, the housing 1 is configured to include an upper shell 11, a middle joint 12, and a lower shell 13 fixedly connected in order from top to bottom. The power main shaft 2 is correspondingly arranged in the upper shell 11 and the middle joint 12, and the output main shaft 4 is correspondingly arranged in the lower shell 13. The middle sub 12 may be a centralizer (spiral centralizer or straight edge centralizer), so that the middle sub 12 can centralize the downhole composite impact tool 100, which is very beneficial to enhancing the performance of the downhole composite impact tool 100.

In one embodiment, the upper housing 11, the middle joint 12 and the lower housing 13 are all fixedly connected by positive and negative tapered connecting buckles. The connection mode is convenient and quick to install, and the connection stability can be effectively guaranteed.

As shown in fig. 1, the bearing string 3 is disposed between the power spindle 2 and the upper housing 11. Preferably, the bearing string 3 is a TC bearing string, which may be, for example, a cemented carbide bearing or a tungsten carbide bearing, wherein TC refers to tungsten carbide, which is the main raw material for producing cemented carbide. The inner ring of the bearing string 3 is in interference fit with the power spindle 2 to form fixed connection, and the outer ring of the bearing string 3 is in fixed connection with the inner wall of the upper shell 11. The power shaft 2 is thereby rotationally connected to the housing 1 via the bearing train 3.

According to the invention, a first upper righting wear-resistant assembly 31 and a second upper righting wear-resistant assembly 32 are respectively arranged at the upper end and the lower end of the bearing string 3. As shown in fig. 1, a first centralizing wear assembly 31 is located radially between the power spindle 2 and the upper housing 11. The first up-centralizing wear assembly 31 includes a first wear stationary ring 311 and a first wear moving ring 312. The first anti-wear static ring 311 is fixedly connected with the inner wall of the upper housing 11, and the lower end surface of the first anti-wear static ring 311 abuts against the upper end surface of the outer ring of the hold-down bearing string 3. In one embodiment, the inner wall of the upper housing 11 is provided with a secondary step with a downward end face, the outer wall of the first anti-abrasion static ring 311 is provided with a secondary step with an upward end face, and the first anti-abrasion static ring 311 and the upper housing 11 are installed in a matching manner through the secondary steps to form axial limitation. The first anti-wear ring 312 is fixedly connected with the power spindle 2, and the lower end surface of the first anti-wear ring 312 abuts against the upper end surface of the inner ring of the hold-down bearing string 3. The first centralizing wear assembly 31 is effective in preventing wear between the power spindle 2 and the upper housing 11.

As shown in fig. 1, a tightening nut 9 is provided at the upper end of the first upper centering wear-resistant assembly 31, and the tightening nut 9 is mounted on the power spindle 2 by screw fastening. The jacking nut 9 is used for locking the first anti-abrasion ring 312 of the first upper righting anti-abrasion assembly 31 on the power spindle 2, so that the first anti-abrasion ring 312 and the power spindle 2 are relatively static, the fixed connection between the first anti-abrasion ring 312 and the power spindle 2 is realized, and the stability of the downhole composite impact tool 100 is enhanced.

In addition, an adjusting pad can be installed at the upper end of the tightening nut 9 and used as an adjusting piece during installation, so that installation is facilitated.

As shown in fig. 1, the second up-right wear assembly 32 corresponds to being radially inward of the middle joint 12. The second up-centralizing wear assembly 32 includes a second wear stationary ring 321 and a second wear moving ring 322. The second wear-proof stationary ring 321 forms a fixed connection with the inner wall of the middle joint 12, and the upper end surface of the second wear-proof stationary ring 321 abuts against the lower end surface of the outer ring of the hold-down bearing string 3. In one embodiment, the inner wall of the middle joint 12 is provided with a step with an upward end surface, and the lower end surface of the second wear-resistant stationary ring 321 abuts against the step to form an axial limit. The second anti-wear ring 322 is fixedly connected with the power spindle 2, and the upper end surface of the second anti-wear ring 322 abuts against the lower end surface of the inner ring of the hold-down bearing string 3. The second up-centralizing wear assembly 32 is effective in preventing wear between the power spindle 2 and the middle sub 12.

In the working process, the first upper righting wear-resistant assembly 31 and the second upper righting wear-resistant assembly 32 can bear the radial force generated by the eccentric motion of a rotor in a downhole motor, the swinging of the shaft body of the universal shaft and the fixed shaft rotation of the power main shaft 2. Thereby, the guiding capability of the downhole composite impact tool 100 and the transmission performance of the power spindle 2 are improved.

According to the invention, a jacking assembly can also be arranged between the bearing string 3 and the second upper righting wear-resistant assembly 32. As shown in fig. 1, the tightening assembly is disposed between the bearing string 3 and the second upper righting wear-resistant assembly 32 in the axial direction, and includes an outer tightening sleeve 33 and an inner tightening sleeve 34. The outer jacking sleeve 33 is used for jacking the lower end face of the outer ring of the bearing string 3, and the inner jacking sleeve 34 is used for jacking the lower end face of the inner ring of the bearing string 3. In one embodiment, the inner clamping sleeve 34 is provided with an internal thread, which forms a fixed connection with the power spindle 2 via the internal thread, thereby clamping the inner ring of the bearing string 3, so that the bearing string 3 is axially limited.

According to one embodiment of the invention, taking a 7 "drill as an example, the pitch of the helical splines 42 on the output spindle 4 is set to be in the range of 100-800mm, and the helix angle of the helix formed by the helical extension of the helical splines 42 is set to be in the range of 5-85 degrees. The helical splines 42 are provided with a width in the range of 40-200mm and a depth in the range of 5-20 mm. Correspondingly, the helically splined groove 22 on the power spindle 2 is fitted with the helical spline 42. In order to facilitate the engagement of the helical spline 42 with the helical spline 22, the width and depth of the helical spline 22 are set to be slightly larger than those of the helical spline 42.

According to the present invention, as shown in fig. 1 to 4, a first eccentric hole 211 communicating with the first central passage 21 is provided in the power main shaft 2, the first eccentric hole 211 being at an axially inner end of the spirally-threaded key groove 22. Meanwhile, a second eccentric hole 411 communicating with the second center flow path 41 is provided at the upper end of the output spindle 4. The axially outer end of the first eccentric hole 211 is formed as a first axial impact surface 212, and the upper end surface of the output spindle 4 is formed as a second axial impact surface 412. During the axial reciprocating motion of the power spindle 2, the distance between the first axial impact surface 212 and the second axial impact surface 412 changes.

In the working process of the downhole composite impact tool 100, before the output main shaft 4 is screwed upwards relative to the power main shaft 2 until reaching the highest point, the first central channel 21 is communicated with the second central flow passage 41 through the first eccentric hole 211 and the second eccentric hole 411 in sequence. At this time, there is a certain distance between the axial end face position where the first eccentric hole 211 is disposed and the axial end face position where the second eccentric hole 411 is disposed, and the first eccentric hole 211 is in a full open state. When the output spindle 4 moves upwards to the highest point, the first axial impact surface 212 of the power spindle 2 and the second axial impact surface 412 of the output spindle 4 are in contact coincidence, so that the first eccentric hole 211 and the second eccentric hole 411 are overlapped and have the minimum conduction area, at this time, the first central channel 21 is conducted with the second central flow channel 41 through the overlapping area of the first eccentric hole 211 and the second eccentric hole 411, and throttling is formed due to the reduction of the area of the overlapping area, so that pressure pulses can be generated. The generated pulse pressure can act on the upper end surface of the output main shaft 4 and then is transmitted to the drill bit, so that the output main shaft 4 can form further axial impact on the drill bit under the action of the pulse pressure, and the method is very favorable for enhancing the impact force of the drill bit and improving the drilling construction of the drill bit.

In order to ensure that the first axial impact surface 212 of the power spindle 2 and the second axial impact surface 412 of the output spindle 4 can be brought into contact with each other and coincide, the maximum distance D between the first axial impact surface 212 and the second axial impact surface 412 is set to be smaller than the axial movement stroke H of the driven member 52 (see fig. 6).

As shown in fig. 1 to 3, an annular limiting groove 43 is provided on the outer surface of the output spindle 4, a through hole 23 is provided on the side wall of the power spindle 2, a drop-preventing pin 6 is installed in the through hole 23, and the axial inner end of the drop-preventing pin 6 extends into the annular limiting groove 43. In the process of entering the well, the anti-falling pin block 6 of the underground composite impact tool 100 can play a good anti-falling role, and the output main shaft 4 is effectively prevented from falling. When the anti-drop pin block 6 is installed, it passes through the through hole 23 from the outside to the inside and is inserted into the annular stopper groove 43. In order to prevent the anti-drop pin 6 from falling out during operation, a sleeve (not shown) is provided at the position of the power spindle 2 corresponding to the through hole 23.

In the present embodiment, the axial width of the annular stopper groove 43 is larger than the axial width of the anti-drop pin 6. Moreover, the value obtained by subtracting the axial width of the anti-drop pin block 6 from the width of the annular limiting groove 43 is larger than the maximum value of the stroke of the output spindle 4 capable of moving axially relative to the power spindle 2, so as to ensure that the axial end face position provided with the first eccentric hole 211 can coincide with the axial end face position provided with the second eccentric hole 411 when the output spindle 4 moves upwards to the highest point.

According to the invention, the output spindle 4 is arranged concentrically inside the lower housing 13, and the cam mechanism 5 is fixedly mounted on the output spindle 4. As shown in fig. 5, the cam 51 in the cam mechanism 5 is configured in a cylindrical shape, and an upper end surface of the cam 51 is formed as a continuous cam surface 511. Fig. 6 shows the deployed configuration of the cam 51. In the embodiment shown in fig. 5 and 6, a three-step cam face is provided on the upper end face of the cam 51. The cam 51 drives the follower 52 to move axially by a stroke H, which is the distance between the highest and lowest working surfaces of the cam 51.

In one embodiment, the inner wall of the cam 51 is provided with an internal thread and the outer wall of the output spindle 4 is provided with a section of an external thread. The cam 51 is fixedly mounted on the output spindle 4 by means of a screw connection. Thereby, the cam 51 can be rotated synchronously with the output spindle 4.

As shown in fig. 7, the driven member 52 is formed in a substantially cylindrical shape, and the inner diameter of the driven member 52 is set larger than the outer diameter of the output rotary shaft 4, whereby the driven member 52 is in clearance fit with the output rotary shaft 4 and the driven member 52 can move in the axial direction of the output spindle 4. The lower end face of the follower 52 is configured to be flat. A plurality of rollers 53 are circumferentially arranged on the lower end surface of the follower 52, and the axial direction of the rollers 53 is along the diameter direction of the follower 52. In the embodiment shown in fig. 7, three rollers 53 are provided on the lower end surface of the follower 52. To facilitate mounting of the roller 53, the lower end surface of the follower 52 may be configured as a stepped surface on which the roller 53 is mounted. The follower 52 is in fitting contact with a cam surface 511 at the upper end of the cam 51 via a roller 53. Thus, when the cam 51 rotates with the output spindle 4, the follower 52 can reciprocate in the axial direction by the roller 53 and the cam surface 511.

In an embodiment not shown, the rollers 53 may also be replaced by balls.

According to the present invention, a limit step 55 with a downward end surface is formed on the inner wall of the housing 1, and the upper end surface of the follower 52 can jack up the upper drill string connected to the housing 1 through the limit step 55. In one embodiment, the lower end of the middle housing 12 extends into the lower housing 13, and the lower end surface of the middle housing 12 is formed as a limit step 55.

As shown in fig. 1, a stopper cylinder 7 is fixed to the lower end of the lower case 13. In one embodiment, the limiting cylinder 7 is fixedly connected with the lower shell 13 through threads. A lower righting anti-abrasion component 8 is arranged between the limiting cylinder 7 and the output main shaft 4. The lower righting anti-abrasion assembly 8 comprises a righting anti-abrasion moving ring and a righting anti-abrasion static ring formed on the inner wall of the limiting cylinder 7. The centering anti-wear ring is fixedly connected with the output spindle 4, for example, by a thread. Wear between the output spindle 4 and the lower housing 13 is thereby effectively prevented by the lower righting wear assembly 8.

The operation of the downhole composite stroker tool 100 according to the present invention is briefly described below. Firstly, the underground composite impact tool 100 is connected to the lower end of the underground motor, and is put into a shaft after being assembled, and the output spindle 4 can be effectively prevented from falling under the action of the anti-falling pin block 6 and the limiting cylinder 7 in the process of putting into the shaft. The drilling tool is activated when the downhole composite impact tool 100 is lowered to a predetermined downhole location.

Under the normal working state, the power spindle 2 is driven by the downhole power motor to rotate, and the power spindle 2 drives the output spindle 4 to rotate through the matching action of the helical spline 42 and the helical spline groove 22, so that the power of the downhole power motor is transmitted to the drill bit. At the same time, on the one hand, the output spindle 4 rotates the cam 51 during rotation, which causes the follower 52 to reciprocate axially under the cooperation of the roller 53 and the cam surface 511 of the cam 51 and, in the upward movement, to jack up the upper drill string connected to the housing 1 until reaching the highest point by the upward movement H (stroke). After the highest point is crossed, the helical spline 42 has a disengagement tendency, and at this time, the output main shaft 41 generates instantaneous speed reduction due to the disengagement of the helical spline 42. Further, the upper drill string and the output spindle 4 form axial and circumferential composite impacts on the helical spline 42 through the helical spline groove 22 under the action of bit weight, and the composite impact force is transmitted to the drill bit. Thereby, axial and circumferential compound impacts are formed on the drill bit.

On the other hand, during the reciprocating axial motion of the power spindle 2, the distance between the first axial impact surface 212 of the power spindle 2 and the second axial impact surface 412 of the output spindle 4 changes periodically, so that the first eccentric hole 211 and the second eccentric hole 411 overlap periodically to form a throttle, thereby generating a pressure pulse. The generated pulse pressure acts on the upper end surface of the output main shaft 4 and is further transmitted to the drill bit, so that the output main shaft 4 forms further axial impact on the drill bit under the action of the pulse pressure, which is very favorable for enhancing the impact force of the drill bit and improving the drilling construction of the drill bit.

When the torque of the drill bit is too large, the output main shaft 4 can adapt to automatic adjustment of underground working conditions, and can be upwards screwed in relative to the power main shaft 2 under the matching action of the spiral spline groove 22 and the spiral spline 42 to absorb certain torque, so that the output main shaft 4 upwards moves relative to the power main shaft 2, the soil depth of the drill bit is reduced, the torque of the drill bit is reduced, the phenomenon of stagnation of an underground motor can be effectively prevented, the underground working performance of the underground composite impact tool 100 is greatly improved, the drilling construction efficiency is greatly improved, and the drilling construction effect is remarkably enhanced.

The downhole composite impact tool 100 according to the invention can drive the power spindle 2 to drive the upper drill string to move axially through the cam mechanism 5, and form axial and circumferential composite impact on the helical spline 42 through the helical spline groove 22, so as to generate axial and circumferential composite impact force on a drill bit. And the downhole composite impact tool 100 can generate pressure pulses and act on the output spindle 4 to form further axial impact on the drill bit, which is very beneficial to enhancing the impact force of the drill bit and improving the drilling construction of the drill bit. In addition, when the torque of the drill bit is too large, the output main shaft 4 can adapt to the underground working condition for automatic adjustment, and can be screwed upwards relative to the power main shaft 2 under the matching action of the spiral spline groove 22 and the spiral spline 42 so as to reduce the soil depth of the drill bit and realize the reduction of the torque of the drill bit, and the phenomenon of the stagnation of the underground motor can be effectively prevented. These are all very favorable to improving the downhole working performance of compound percussion tool 100 in the pit, have greatly improved and bored the efficiency of construction, have strengthened and bored the construction effect apparently. In addition, the underground composite impact tool 100 is convenient to operate, can adapt to the underground actual working condition in the working process, is automatically adjusted, and has strong adaptability.

In the description of the present invention, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to imply that the number of technical features indicated is significant. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing examples, or that equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A downhole composite stroker tool, comprising:

a cylindrical housing (1);

the power main shaft (2) is used for connecting a downhole power motor, the power main shaft is concentrically arranged in the shell and can rotate relative to the shell, the power main shaft is provided with a first central flow passage (21), and the inner wall surface of the power main shaft is provided with a spiral spline (22) extending along the axial part;

the output main shaft (4) is used for connecting a drill bit, the output main shaft is provided with a second central flow passage (41), and the outer wall surface of the output main shaft is provided with a spiral spline (42) which can be matched with the spiral spline groove; and

the cam mechanism (5) comprises a cam (51) fixedly sleeved on the output spindle and a driven piece (52) arranged at the upper end of the cam, wherein the upper end of the cam is constructed into a continuous cam surface (511), the lower end of the driven piece is constructed into a plane and is provided with a plurality of rollers (53) which are uniformly distributed in the circumferential direction, and the rollers are in fit contact with the cam surface;

the power main shaft can drive the output main shaft to rotate, the driven part can reciprocate axially under the action of the cam and jack up an upper drill string connected with the shell, so that after the upper drill string and the output main shaft move to the highest point of travel, axial and circumferential composite impact can be formed on the spiral spline through the spiral spline groove under the action of bit pressure and is transmitted to the drill bit.

2. A downhole composite impact tool according to claim 1, characterized in that a limit step (55) is formed on the inner wall of the housing facing downwards, by means of which limit step the upper end face of the follower can jack up an upper drill string connected to the housing.

3. The downhole composite impact tool of claim 1, wherein the helical spline has a pitch set in the range of 100-800mm and the helical spline extends helically to form a helix having a helix angle in the range of 5-85 degrees.

4. The downhole composite impact tool according to claim 1 or 3, wherein the helical splines are arranged with a width in the range of 40-200mm and a depth in the range of 5-20 mm.

5. A downhole composite impact tool according to claim 1, wherein a first eccentric bore (211) is provided in the power spindle in communication with the first central channel, the first eccentric bore being at an axially inner end of the helically splined groove, and a second eccentric bore (411) is provided in the upper end of the output spindle in communication with the second central flow channel, the first eccentric bore and the second eccentric bore being capable of forming a restriction when overlapping, thereby generating a pressure pulse.

6. A downhole compound stroker tool according to claim 5, wherein an axially outer end of the first eccentric bore is formed as a first axial stroker face (212) and an upper end face of the output spindle is formed as a second axial stroker face (412), a maximum distance D between the first and second axial stroker faces being smaller than an axial stroke H of movement of the follower.

7. A downhole composite impact tool according to claim 1, wherein an annular limiting groove (43) is provided on an outer surface of the output spindle, a through hole (23) is provided on a side wall of the power spindle, a drop-preventing pin block (6) is mounted in the through hole, an axially inner end of the drop-preventing pin block extends into the annular limiting groove,

the axial width of the annular limiting groove is larger than the width of the anti-falling pin block.

8. A downhole composite impact tool according to claim 1, wherein the housing is configured to comprise an upper housing (11), a middle joint (12) and a lower housing (13) fixedly connected in sequence from top to bottom.

9. A downhole composite impact tool according to claim 8, wherein a bearing string (3) is sleeved on the power main shaft, the bearing string is located between the upper housing and the power main shaft, and a first upper centering wear prevention assembly (31) and a second upper centering wear prevention assembly (32) are respectively arranged at two ends of the bearing string.

10. The downhole composite impact tool according to claim 8, wherein a limiting cylinder (7) is fixedly connected to the lower end of the lower housing, and a lower centering wear assembly (8) is arranged between the limiting cylinder and the output spindle.

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