CN217558251U - Shock-absorbing anti-inclination speed-raising drilling tool combination for large-borehole straight well section - Google Patents

Abstract

The utility model discloses a large-hole straight well section shock-absorbing anti-inclination speed-raising drilling tool combination, wherein a drill bit is connected below a single-bending screw rod, the single-bending screw rod is connected at the lower end of a flexible propeller, the flexible propeller is connected below a stabilizer, and a medium-size drill collar, a small-size drill collar and a drill rod are sequentially connected above the stabilizer; the floating core shaft is inserted into a central hole channel of a shell of the flexible propeller from bottom to top, the upper end of the floating core shaft is positioned in an inner cavity of an upper joint of the shell and is screwed with a pressure-bearing joint, a core shaft shoulder is arranged at the lower part of the floating core shaft and is supported below a lower port of a lower joint of the shell, the floating core shaft and the pressure-bearing joint are both provided with central hole channels which are communicated with the central hole channel of the upper joint of the shell, a core shaft tenon extending along the axial direction is arranged on the periphery of the middle part of the floating core shaft, axial long grooves are symmetrically arranged on the inner wall of the joint in the shell, and the core shaft tenon is respectively embedded in the axial long grooves. The combined drill bit has stable working state and long service life, and can realize safe, efficient and rapid drilling.

Description

Shock-absorbing anti-inclination speed-raising drilling tool combination for large-borehole straight well section

Technical Field

The utility model relates to an oil drilling tool combination especially relates to a speed-raising drilling tool combination is prevented inclining by shock attenuation of borehole vertical shaft section, belongs to oil drilling tool technical field.

Background

In petroleum drilling, a well bore starts to drill from the zero well depth, which is called first drilling, and is called first drilling for short; a drilled wellbore is the largest, closest to the surface, and a surface casing is run in an open wellbore and cemented. And (4) drilling after the surface casing is well-cemented, namely second drilling, and running the technical casing in the second drilled well and cementing the well. And (3) drilling after the technical casing is cemented, namely third drilling, three openings for short, and placing the technical casing in the three-opening borehole for cementing.

In the petroleum engineering drilling construction, the speed of an upper large-size well bore (406.4 mm or more) is increased by adopting a mode of composite drilling of a PDC drill bit, a screw rod, a drill collar, a drill rod and a kelly bar, wherein the drilling mode can effectively improve the drilling speed of a drilling machine, shorten the drilling period and save the drilling cost. However, in the actual operation process, the following problems are likely to occur:

1. the big well bore is located the upper strata nearer than apart from the earth's surface, because the reason in the aspect of geological settlement etc. often bores and meets heterogeneous stratum such as gravel-containing stratum, soft and hard interaction stratum, the more isopiestic stratum of stereoplasm intermediate layer, often can cause vibration such as PDC drill bit spring, stick-slip and whirl, causes the job instability of PDC drill bit at the shaft bottom, and drill bit cutting teeth damages in advance, leads to that the drill bit footage is slow, mechanical drilling speed and life-span reduce.

2. The drilling tool is axially vibrated due to high-frequency jumping caused by the fact that the drilling tool meets gravel stratum, the neutral point of the drilling tool is changed back and forth due to the axial vibration, and the drilling tool above and below the neutral point is respectively under the action of tension and pressure, so that the drilling tool is prone to fatigue damage due to frequent changing of the neutral point, and faults such as drilling tool failure are caused.

3. In the drilling process, because the bit pressure applied to the bit manually is uneven and untimely, the bit pressure applied to the bit is insufficient, and the bit does not constantly keep the optimal degree to be absorbed into the stratum, the mechanical drilling speed of the PDC bit is low.

4. In the drilling process, because of the requirement of oblique drilling prevention, a small bit pressure oblique drilling prevention mode is often adopted, so that the limitation of improving the mechanical drilling speed is caused.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome the problem that exists among the prior art, provide a straight well section shock attenuation of big well and prevent oblique acceleration drilling tool assembly, the operating condition of PDC drill bit is stable, and long service life can realize safe, high-efficient, the quick drilling of the straight well section of big well.

In order to solve the technical problem, the utility model discloses a big well straight well section shock attenuation prevents inclined acceleration drilling tool combination, including the PDC drill bit, the PDC drill bit is connected in the below of single-turn screw rod, the single-turn screw rod is connected in the lower extreme of flexible propeller, the flexible propeller is connected in the below of stabilizer, the stabilizer is connected in the lower extreme of medium-size drill collar, the medium-size drill collar is connected in the lower extreme of small-size drill collar, the small-size drill collar is connected in the lower extreme of drilling rod; the flexible propeller comprises a shell upper joint, a shell middle joint and a shell lower joint which are sequentially screwed, a floating mandrel is inserted into a shell central hole passage from bottom to top, the upper end of the floating mandrel is positioned in an inner cavity of the shell upper joint and is screwed with a pressure-bearing joint, a mandrel shoulder is arranged at the lower part of the floating mandrel and is supported below a lower port of the shell lower joint, the floating mandrel and the pressure-bearing joint are both provided with central hole passages communicated with the central hole passage of the shell upper joint, a mandrel tenon extending along the axial direction is arranged on the periphery of the middle part of the floating mandrel, axial long grooves are symmetrically arranged on the inner wall of the shell middle joint, and the mandrel tenon is respectively embedded into the axial long grooves.

As the improvement of the utility model, the upper portion of casing top connection is equipped with the casing top connection box, the below of casing top connection box is equipped with the undergauge step, the pressure-bearing joint is located the below of undergauge step.

As a further improvement, the periphery of the pressure-bearing joint is uniformly provided with overflow grooves which are axially communicated respectively.

As a further improvement of the utility model, the PDC drill bit is phi 406.4mm tricone PDC drill bit, the external diameter of single curved screw rod is phi 244.5mm, the external diameter of flexible propeller is phi 228.6mm, the external diameter of stabilizer is phi 402mm, the external diameter of medium-sized drill collar is phi 228.6mm, the external diameter of small-sized drill collar is phi 203.2mm, the external diameter of drilling rod is phi 139.7mm.

As a further improvement, the medium-sized drill collars are three, and the small-sized drill collars are six.

As a further improvement of the present invention, the single-bending screw includes a hydraulic motor, the lower end of the hydraulic motor is connected to a universal shaft assembly, the lower end of the universal shaft assembly is connected to a transmission shaft assembly, the universal shaft assembly includes a connecting rod located in the middle and universal joints respectively connected to both ends of the connecting rod, both ends of the connecting rod are respectively inserted into the counter bores of the universal joints, the peripheries of both ends of the connecting rod are respectively provided with outer drum-shaped teeth, the outer drum-shaped teeth are engaged with the inner drum-shaped teeth of the inner peripheral wall of the counter bore of the universal joint, the centers of both ends of the connecting rod are respectively embedded with a top block, and the ball head of the top block is respectively abutted against the center of the bottom wall of the counter bore of the universal joint; shoulders at two ends of the connecting rod respectively abut against the inner angle bearing, the outer spherical surface of the inner angle bearing is supported on the inner spherical surface of the outer angle bearing, and the inner end of the outer angle bearing abuts against the inner step of the universal joint; the outer ports of the counter bores of the universal joints are respectively covered with a gland, the outer edges of the glands are respectively fixed on the corresponding universal joints through screws, inner end faces of the glands are respectively provided with inner convex rings of the glands, and the inner convex rings of the glands respectively abut against the bottoms of the outer corner bearings.

As a further improvement, the transmission shaft assembly comprises a transmission shaft casing and a transmission mandrel, the lower end of the transmission mandrel is followed stretch out and be connected with the transmission shaft lower joint in the lower port of the transmission shaft casing, the PDC drill bit is screwed in the toper box of the transmission shaft lower joint, the middle section of the transmission shaft casing is equipped with nearly drill bit centralizer.

As a further improvement of the utility model, the periphery of cardan shaft assembly is equipped with the cardan shaft casing, be equipped with between the lower part of cardan shaft casing and the transmission shaft casing and transfer curved casing, transfer curved casing the angle be 0.5-1 degree the external diameter of nearly drill bit centralizer is phi 398mm.

Compared with the prior art, the utility model discloses following beneficial effect has been obtained: 1. the flexible thruster with the corresponding size is added in the conventional drilling tool assembly, and the phenomenon of bit jump during drilling in heterogeneous strata such as gravel-containing strata, soft and hard staggered strata, more hard interlayers and the like is reduced by utilizing the liquid elastic energy absorption effect of the flexible thruster, so that the cutting teeth of the PDC bit are protected, and the service life of the bit is prolonged.

2. Simple structure, cost of manufacture is compared in current drilling tool with use cost and is roughly equivalent, the stable performance, and the use can not bring the risk in other aspects for the drilling operation. The cost of the flexible propeller is only increased, the flexible propeller can be recycled, and the average single well sharing cost is low.

3. By prolonging the service life of the PDC drill bit, reducing the staggered transformation of the axial stress of the drilling tool and improving the capability of the drill bit to continuously bite into the stratum, the construction speed can be obviously improved, the risk of the drilling tool is reduced, the drilling aging proportion is improved, and good economic benefit can be achieved.

4. The combined drilling is realized by mechanical driving of the kelly bar and hydraulic driving of the single-bent screw, so that the drilling speed of the PDC drill bit can be effectively improved, the drilling period is shortened, and the drilling cost is saved. The guiding can be carried out while advancing the ruler, and the function of preventing oblique straightening is achieved.

5. The universal shaft assembly can transfer larger torque, has strong capability of bearing radial load and axial load, has excellent self-aligning function, stable working state, difficult damage or fault and long service life.

Drawings

The invention is described in further detail below with reference to the attached drawings and the detailed description, wherein the drawings are provided for reference and illustration purposes only and are not intended to limit the invention.

FIG. 1 is a schematic structural view of the shock-absorbing, inclination-preventing and speed-raising drilling tool assembly for a vertical well section of a large well of the utility model;

FIG. 2 is a schematic structural view of a middle single-bending screw rod of the present invention;

FIG. 3 is a schematic view of the structure of a rotor in a single-bent screw;

FIG. 4 is a schematic structural view of a cardan shaft assembly in a single-bent screw;

fig. 5 is an enlarged view of the upper portion of fig. 4.

Fig. 6 is a front view of the middle flexible propeller of the present invention.

In the figure: A.PDC drill bit; B. a single-bent screw; C. a flexible propeller; D. a stabilizer; E. medium-sized drill collars; f, a small-size drill collar; G. a drill stem; 1. an upper joint of the screw rod; 2. a bypass valve; 3. an anti-drop assembly; 3a, an anti-falling device; 4. a hydraulic motor; 4a, a screw rotor; 5. a cardan shaft assembly; 5a, universal joint; 5a1. Inner drum-shaped teeth; 5a2, a radial oil hole; 5a3, sealing a screw plug; 5b, connecting rod; 5b1. External drum teeth; 5c, a top block; 5d, inner angle bearing; 5e, an external angle bearing; 5f, pressing the cover; 5f1, pressing the inner convex ring of the cover; 5g, pressing an O-shaped ring; 5h, sealing the end face; 6. bending the shell; 7. a drive shaft assembly; 7a, a transmission mandrel; 7b, a lower joint of the transmission shaft; 8. a near bit centralizer; 9. the upper joint of the shell; 9a, connecting a female buckle on the shell; 9b, reducing the diameter of the step; 10. a housing middle joint; 10a, an axial long groove; 11. a pressure-bearing joint; 11a, a flow through groove; 12. a floating mandrel; 12a, mandrel tenon; 12b, mandrel shoulder; 13. the lower joint of the shell.

Detailed Description

In the following description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, and do not mean that the device must have a specific orientation.

As shown in figure 1, the utility model discloses the straight well section shock attenuation of big well is prevented oblique speeding up drilling tool combination includes PDC drill bit A, single curved screw rod B, flexible propeller C, stabilizer D, medium-size drill collar E, small-size drill collar F and drilling rod G, PDC drill bit A connects the below at single curved screw rod B, single curved screw rod B connects the lower extreme at flexible propeller C, flexible propeller C connects the below at stabilizer D, stabilizer D connects the lower extreme at medium-size drill collar E, medium-size drill collar E connects the lower extreme at small-size drill collar F, small-size drill collar F connects at drilling rod G lower extreme.

As shown in fig. 2 to 5, the single-bending screw B includes a screw upper joint 1, a bypass valve 2, an anti-drop assembly 3, a hydraulic motor 4, a cardan shaft assembly 5, a propeller shaft assembly 7, and a near-bit centralizer 8. The universal shaft assembly 5 is connected to the lower end of the hydraulic motor 4, and the transmission shaft assembly 7 is connected to the lower end of the universal shaft assembly 5. The universal shaft assembly 5 comprises a connecting rod 5b positioned in the middle and universal joints 5a respectively connected to two ends of the connecting rod 5b, and the outer ends of the universal joints 5a are respectively provided with a conical male buckle; two ends of the connecting rod 5b are respectively inserted into the counter bores of the universal joints 5a, the peripheries of the two ends of the connecting rod 5b are respectively provided with an outer crowned tooth 5b1, the outer crowned tooth 5b1 is meshed with the inner crowned teeth 5a1 on the inner peripheral walls of the counter bores of the universal joints, the centers of the two ends of the connecting rod 5b are respectively embedded with ejector blocks 5c, and the ejector blocks 5c are respectively abutted against the centers of the bottom walls of the counter bores of the universal joints 5a.

The jacking block 5c jacks the axle center of the universal joint 5a, can bear huge axial force, and has a centering function; the connecting rod 5b can swing around the ball head of the top block 5c by a certain angle to adapt to the deviation between the axis of the connecting rod and the axis of the universal joint. The outer crowned teeth 5b1 are meshed with the inner crowned teeth 5a1, so that the torque from the motor can be reliably transmitted to the transmission shaft and the drill bit, a certain aligning function is realized, the coaxiality error of the upper end and the lower end is automatically compensated, the meshing between the crowned teeth is reliable, and the crowned teeth are not easy to break.

Shoulders at two ends of the connecting rod 5b are respectively abutted against an inner angle bearing 5d, an outer spherical surface of the inner angle bearing 5d is supported on an inner spherical surface of an outer angle bearing 5e, and an inner end of the outer angle bearing 5e is abutted against an inner step of the universal joint 5 a; the outer ports of the counter bores of the universal joints are respectively covered with a gland 5f, the outer edges of the glands 5f are respectively fixed on the corresponding universal joints 5a through screws, inner convex rings 5f1 of the glands are respectively arranged on the inner end faces of the glands 5f, and the inner convex rings 5f1 of the glands are respectively abutted against the bottoms of the outer angle bearings 5e.

The inner angle bearing 5d is supported on the outer angle bearing 5e, has great load capacity, can bear radial load and axial load, and is stable and reliable. The inner angle bearing 5d has self-aligning function by matching the outer spherical surface with the inner spherical surface of the outer angle shaft. The gland 5f realizes the positioning between the universal joint 5a through a screw, and the inner convex ring 5f1 of the gland presses the bottom of the outer angle bearing 5e to realize the axial positioning.

The inner circumferential wall of the gland 5f is embedded with a gland O-shaped ring 5g to realize sealing with the outer wall of the connecting rod 5b, and the inner end plane of the gland 5f is embedded with an end face sealing ring 5h to realize sealing with the port of the universal joint 5a. The inner angle bearing 5d, the outer angle bearing 5e, the top block 5c, the outer drum-shaped teeth 5b1 and the inner drum-shaped teeth 5a1 are sealed by the gland O-shaped ring 5g and the end face sealing ring 5h, so that underground corrosive liquid is prevented from being contacted, and good lubrication is ensured.

The circumference of the universal joint 5a is provided with a radial oil filling hole 5a2, the inner port of the radial oil filling hole 5a2 is communicated with the bottom space of the counter bore of the universal joint, and the outer port of the radial oil filling hole 5a2 is screwed with a sealing plug screw 5a3. Before entering the well, lubricating oil is injected into the meshing space through the radial oil injection hole 5a2, and then the outer end of the radial oil injection hole 5a2 is closed by screwing up the sealing screw plug 5a3. The outer crowned teeth 5b1 and the inner crowned teeth 5a1 are well meshed, the inner corner bearings 5d and the outer corner bearings 5e are well matched, and the top block 5c is well lubricated.

The inner cavity of the shell of the hydraulic motor 4 is provided with a screw motor, the upper end of the screw motor is connected below the anti-falling device 3a, the anti-falling device 3a is suspended in the shell of the anti-falling assembly 3, the shell of the anti-falling assembly 3 is screwed below the bypass valve 2, and the upper end of the bypass valve 2 is screwed below the screw upper joint 1. The screw motor includes a screw rotor 4a and a housing stator.

The transmission shaft assembly 7 comprises a transmission shaft shell and a transmission mandrel 7a, the lower end of the transmission mandrel 7a extends out of the lower port of the transmission shaft shell and is connected with a transmission shaft lower joint 7b, a near bit centralizer 8 is arranged at the middle section of the transmission shaft shell, and the upper end of a PDC bit A is screwed in a conical female buckle of the transmission shaft lower joint 7b.

The periphery of the cardan shaft assembly 5 is provided with a cardan shaft shell, a bending adjusting shell 6 is arranged between the lower portion of the cardan shaft shell and the transmission shaft shell, the angle of the bending adjusting shell 6 is 0.5-1 degrees, guiding can be performed while footage is carried out, and the function of preventing oblique straightening is achieved. The bending degree of the screw drill is small, the composite drilling safety risk is low, and the service life of the screw drill is long; the swing amplitude is small, the vibration is reduced, and the PDC drill bit A is protected.

As shown in fig. 6, the flexible propeller C includes a housing upper joint 9, a housing middle joint 10 and a housing lower joint 13 which are screwed in sequence, a floating mandrel 12 is inserted into a central duct of the housing from bottom to top, the upper end of the floating mandrel 12 is located in an inner cavity of the housing upper joint 9 and is screwed with a pressure-bearing joint 11, a housing upper joint female buckle is arranged on the upper portion of the housing upper joint 9, a reducing step 9b is arranged below the housing upper joint female buckle 9a, and the pressure-bearing joint 11 is located below the reducing step 9b.

The periphery of the pressure-bearing joint 11 is uniformly and respectively provided with an axial through flow-passing groove 11a so as to adjust the sectional area of the pressure-bearing joint 11 and avoid the lower cavity from being suppressed.

The lower part of the floating mandrel 12 is provided with a mandrel shoulder 12b, the mandrel shoulder 12b is supported below the lower port of the shell lower joint 13, the floating mandrel 12 and the pressure-bearing joint 11 are both provided with central ducts which are communicated with the central duct of the shell upper joint 9, the periphery of the middle part of the floating mandrel 12 is provided with a mandrel tenon 12a extending along the axial direction, the inner wall of the joint 10 in the shell is symmetrically provided with axial elongated slots 10a, and the mandrel tenon 12a is respectively embedded in the axial elongated slots 10a, can float up and down and can transmit torque.

When the slurry pump is started and the hydraulic cavity at the upper part of the pressure-bearing joint 11 is pressurized, the pressure-bearing joint 11 pushes the floating mandrel 12 to move downwards, the mandrel tenon 12a is embedded in the axial elongated slot 10a of the joint 10 in the shell to slide, relative rotation is avoided, and the torque of the upper joint can be transmitted to the floating mandrel 12. The floating mandrel 12 drives the drill collar and the PDC drill bit A below to move downwards, drilling pressure is applied to the PDC drill bit A, and the medium-sized drill collar E is flexibly connected with the single-bent screw B through the flexible propeller C. The calculation formula of the weight on bit generated by the pressure-bearing joint 11 is as follows: f = Δ P × S. Wherein, the cross section of the S-pressure bearing joint; Δ P-pressure drop.

When the PDC drill bit A is drilled in heterogeneous strata such as gravel strata, soft and hard staggered strata, hard interlayers and the like, the hydraulic elasticity of the flexible propeller C can absorb energy and reduce vibration, the drilling process is prevented from jumping, the cutting teeth of the PDC drill bit A are protected, and the service life of the PDC drill bit A is prolonged.

The corresponding hydraulic elastic energy absorption and shock absorption functions of the flexible propeller C reduce the neutral point height of the bottom drilling tool assembly, improve the stress stable state of the drilling tool and avoid the drilling tool fault caused by fatigue damage of the drilling tool due to the fact that the drilling tool is subjected to alternating stress.

The bit pressure unevenness caused by manual pressurization is reduced by the hydraulic flexible pressurization effect of the flexible propeller C, and the bit pressure is automatically compensated when the bit pressure is insufficient, so that the stress of the drill bit is stable and uniform, and the efficiency of the drill bit entering the stratum is improved. The flexible propeller C plays a role in energy absorption and shock absorption, effectively protects the PDC drill bit A and reduces the risk of the drilling tool.

And drilling by using a conventional turntable, arranging a flexible propeller between drill collar columns, using a part of drill collar to meet a rated drilling pressure value, and then compensating to a reasonable drilling pressure by using the flexible propeller.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention. In addition to the above embodiments, the present invention may have other embodiments. All the technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope claimed by the present invention. The undescribed technical features of the present invention can be realized by or using the prior art, and are not described herein again.

Claims (8)

1. The utility model provides a big well bore straight well section shock attenuation prevents oblique acceleration drilling tool combination, includes the PDC drill bit, its characterized in that: the PDC drill bit is connected below a single-bent screw rod, the single-bent screw rod is connected to the lower end of a flexible propeller, the flexible propeller is connected below a stabilizer, the stabilizer is connected to the lower end of a medium-sized drill collar, the medium-sized drill collar is connected to the lower end of a small-sized drill collar, and the small-sized drill collar is connected to the lower end of a drill rod; the flexible propeller comprises a shell upper joint, a shell middle joint and a shell lower joint which are sequentially screwed, a floating mandrel is inserted into a shell central hole passage from bottom to top, the upper end of the floating mandrel is positioned in an inner cavity of the shell upper joint and is screwed with a pressure-bearing joint, a mandrel shoulder is arranged at the lower part of the floating mandrel and is supported below a lower port of the shell lower joint, the floating mandrel and the pressure-bearing joint are both provided with central hole passages communicated with the central hole passage of the shell upper joint, a mandrel tenon extending along the axial direction is arranged on the periphery of the middle part of the floating mandrel, axial long grooves are symmetrically arranged on the inner wall of the shell middle joint, and the mandrel tenon is respectively embedded into the axial long grooves.

2. The shock-absorbing and inclination-preventing acceleration drilling assembly for the straight well section of the large well bore according to claim 1, is characterized in that: the upper portion of casing top connection is equipped with casing top connection box, the below of casing top connection box is equipped with the undergauge step, the pressure-bearing joint is located the below of undergauge step.

3. The large-borehole straight-well section shock-absorbing and inclination-preventing acceleration drilling assembly according to claim 1, characterized in that: and the peripheries of the pressure-bearing joints are uniformly and respectively provided with axial through flow grooves.

4. The shock-absorbing and inclination-preventing acceleration drilling assembly for the straight well section of the large well bore according to claim 1, is characterized in that: the PDC drill bit is a phi 406.4mm tricone PDC drill bit, the outer diameter of the single bending screw is phi 244.5mm, the outer diameter of the flexible propeller is phi 228.6mm, the outer diameter of the stabilizer is phi 402mm, the outer diameter of the medium-sized drill collar is phi 228.6mm, the outer diameter of the small-sized drill collar is phi 203.2mm, and the outer diameter of the drill rod is phi 139.7mm.

5. The large-borehole straight-well section shock-absorbing and inclination-preventing acceleration drilling assembly according to claim 1, characterized in that: the number of the medium-sized drill collars is three, and the number of the small-sized drill collars is six.

6. The shock-absorbing and inclination-preventing acceleration drilling assembly for the straight well section of the large well bore according to claim 1, is characterized in that: the single-bending screw comprises a hydraulic motor, the lower end of the hydraulic motor is connected with a universal shaft assembly, the lower end of the universal shaft assembly is connected with a transmission shaft assembly, the universal shaft assembly comprises a connecting rod positioned in the middle and universal joints respectively connected to the two ends of the connecting rod, the two ends of the connecting rod are respectively inserted into counter bores of the universal joints, the peripheries of the two ends of the connecting rod are respectively provided with outer drum-shaped teeth, the outer drum-shaped teeth are meshed with inner drum-shaped teeth on the inner peripheral wall of the counter bore of the universal joint, the centers of the two ends of the connecting rod are respectively embedded with a top block, and the ball heads of the top blocks respectively abut against the center of the bottom wall of the counter bore of the universal joint; shoulders at two ends of the connecting rod respectively abut against the inner angle bearing, the outer spherical surface of the inner angle bearing is supported on the inner spherical surface of the outer angle bearing, and the inner end of the outer angle bearing abuts against the inner step of the universal joint; the outer ports of the counter bores of the universal joints are respectively covered with a gland, the outer edges of the glands are respectively fixed on the corresponding universal joints through screws, inner end faces of the glands are respectively provided with inner convex rings of the glands, and the inner convex rings of the glands respectively abut against the bottoms of the outer corner bearings.

7. The shock-absorbing and inclination-preventing acceleration drilling assembly for the straight well section of the large well bore according to claim 6, wherein: the transmission shaft assembly comprises a transmission shaft shell and a transmission mandrel, the lower end of the transmission mandrel extends out of the lower port of the transmission shaft shell and is connected with a transmission shaft lower joint, the PDC drill bit is screwed in a conical female buckle of the transmission shaft lower joint, and a near drill bit centralizer is arranged in the middle section of the transmission shaft shell.

8. The shock-absorbing and inclination-preventing acceleration drilling assembly for the vertical well section of the large well bore according to claim 7, wherein: the periphery of the universal shaft assembly is provided with a universal shaft shell, a bending adjusting shell is arranged between the lower portion of the universal shaft shell and the transmission shaft shell, the angle of the bending adjusting shell is 0.5-1 degrees, and the outer diameter of the near-bit centralizer is phi 398mm.

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