阅读说明：本技术 一种井下位移式冲击方法及冲击钻具 (Down-hole displacement type impact method and impact drilling tool ) 是由 易先中 张仕帆 夏广坤 赵鑫波 王宴滨 柯扬船 万继方 周元华 于 2021-07-12 设计创作，主要内容包括：本发明公开了一种井下位移式冲击方法及冲击钻具,涉及钻井工具领域,包括均由环空结构组成且从上到下依次连接的过流套、第一主轴、承冲座和第二主轴,所述承冲座上从上到下依次连接有振动套、启振座和冲击头,所述振动套与所述冲击头通过连接套连接固定；所述启振座通过花键连接的方式实现与所述承冲座的同步转动,所述启振座在旋转过程中产生轴向上下周期性的位移；该钻井工具是利用旋转能量和冲击能量两种方式进行破岩,能够实现水平井及大位移井的井底加压,产生高频率周期性的冲击力与静压旋转联合作用破碎岩石。(The invention discloses an underground displacement type impact method and an impact drilling tool, which relate to the field of drilling tools and comprise an overflowing sleeve, a first main shaft, a punching bearing seat and a second main shaft which are all composed of annular structures and are sequentially connected from top to bottom, wherein the punching bearing seat is sequentially connected with a vibrating sleeve, a vibration starting seat and an impact head from top to bottom, and the vibrating sleeve and the impact head are fixedly connected through a connecting sleeve; the vibration starting seat is connected with the impact bearing seat through a spline to realize synchronous rotation with the impact bearing seat, and the vibration starting seat generates axial up-down periodic displacement in the rotation process; the drilling tool breaks rock by using two modes of rotation energy and impact energy, can realize bottom hole pressurization of a horizontal well and a large-displacement well, and generates high-frequency periodic impact force and static pressure rotation combined action to break rock.)

1. The underground displacement type percussion drill comprises an overflow sleeve (1), a first main shaft (6), a percussion bearing seat (16) and a second main shaft (23) which are all composed of annular structures and are sequentially connected from top to bottom, and is characterized in that the percussion bearing seat (16) is sequentially connected with a vibrating sleeve (12), a vibration starting seat (13) and an impact head (15) from top to bottom, and the vibrating sleeve (12) and the impact head (15) are fixedly connected through a connecting sleeve (14); the vibration starting seat (13) is connected with the impact bearing seat (16) in a spline mode to synchronously rotate, and the vibration starting seat (13) generates axial up-down periodic displacement in the rotating process.

2. A downhole displacement percussion drill tool according to claim 1, wherein an intermediate joint (7) is arranged between the first main shaft (6) and the impact socket (16), the intermediate joint (7) being threaded such that the first main shaft (6) and the impact socket (16) are synchronously connected.

3. A downhole displacement percussion drill according to claim 2, wherein the end surface of the intermediate connector (7) connected to the impact socket (16) forms a space with a vibration sleeve (12) arranged on the impact socket (16), in which space a spring (10) is mounted.

4. A downhole displacement type percussion drill according to claim 3, wherein the outer walls of the vibration sleeve (12) and the impact head (15) are respectively provided with a steel ball (32), the steel ball (32) is used for supporting the vibration sleeve (12) and the impact head (15), a second outer shell (11) is further arranged on the periphery of the steel ball (32), and one end of the second outer shell (11) is in threaded connection with the intermediate joint (7).

5. The downhole displacement type percussion drill according to claim 4, wherein a PDC bearing dynamic ring (18), a PDC bearing static ring (19), a lower TC dynamic ring (20), a lower TC static ring (21) and a lower joint (22) are sequentially sleeved on the joint of the impact bearing seat (16) and the second main shaft (23), the PDC bearing static ring (19) is forbidden to be kept, and the PDC bearing dynamic ring (18) and the second main shaft (23) rotate together.

6. A downhole displacement percussion drill according to claim 5, wherein a TC radial bearing (4) and a rolling ball bearing (5) for supporting the first spindle (6) are mounted from top to bottom outside the first spindle (6), the TC radial bearing (4) and the rolling ball bearing (5) being lockingly connected by a spindle locknut (3).

7. A downhole displacement percussion drill according to claim 6, wherein the ball bearing (5) comprises an inner race, an outer race and a steel ball (32), the inner and outer races of the bearing having circular raceways.

8. A downhole displacement percussion drill according to claim 7, wherein the TC radial bearing (4) and the rolling ball bearing (5) are further provided with a first housing (2) at their periphery, the first housing (2) being in threaded connection with the intermediate joint (7); the first outer shell (2), the intermediate joint (7) and the second outer shell (11) are subjected to quenching and tempering treatment, wherein the hardness HB is 250-.

9. The downhole displacement percussion drill according to claim 8, wherein the vibration-starting seat (13) is a displacement bearing consisting of an upper vibration-starting body and a lower vibration-starting body, and the circular-developed lines of the groove pitch circle of the steel balls (32) of the upper vibration-starting body and the lower vibration-starting body of the vibration-starting seat (13) have four structures of sine or cosine harmonic groove shape, sawtooth groove shape, rectangular groove shape and triangular groove shape.

10. A downhole displacement percussion method, characterized in that the downhole displacement percussion method uses the downhole displacement percussion drill tool according to claim 9, and the axial displacement is generated by the relative motion of the upper and lower vibration-starting bodies to cause the percussion; impact is caused when the small ball in the lower vibration generating body and the groove of the upper vibration generating body are extruded; when the extrusion disappears, the lower vibration starting body is pulled back to the original position by the spring.

Technical Field

The invention relates to the field of drilling tools, in particular to a downhole displacement type percussion drilling tool and a percussion method for drilling a deep well hard formation.

Background

At present, most of drilling modes are rotary rock breaking drilling, namely, during working, the drilling work is realized only by utilizing shearing force generated by a drill bit. The rotary drilling mode completes the breaking of the rock, but when the rotary drilling mode is used for hard stratum, if the generated torque does not reach the rock breaking degree, the drill bit stops rotating instantly, if the torque is concentrated to reach the rock breaking degree, the torque is suddenly released, impact load which is much larger than usual is generated on the drill bit teeth, and finally the drill bit fails.

On the other hand, the rotary drilling method is only adopted, so that a deflection moment is easily formed on the drill bit, and a well deviation condition is caused during the drilling process, particularly when the drilling is carried out on hard rock and complex strata.

The above conditions not only cause great damage to the drilling tool, but also cause great influence on the cost investment; therefore, improvements to drilling tools, particularly drilling methods, have become a challenge for designers.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a novel percussion drill, namely, the drilling tool, an underground power motor and a drill bit are utilized to work in a combined manner, so that two rock breaking energies of rotation and displacement impact are provided for the drill bit; the anti-deviation device is suitable for the anti-deviation in drilling of complex strata such as rapid drilling of hard rock strata, high and steep structures and the like, and can realize the purposes of pressurizing a bottom hole drill bit of a horizontal well and a large-displacement well, improving the drilling speed and reducing the drilling cost.

The specific scheme provided by the invention is as follows:

the underground displacement type percussion drill comprises an overflow sleeve, a first main shaft, a percussion bearing seat and a second main shaft which are all composed of annular structures and sequentially connected from top to bottom, wherein a vibration sleeve, a vibration starting seat and an impact head are sequentially connected to the percussion bearing seat from top to bottom, and the vibration sleeve and the impact head are fixedly connected through a connecting sleeve; the vibration starting seat is connected with the impact bearing seat through a spline to synchronously rotate, and the vibration starting seat generates axial up-down periodic displacement in the rotating process.

Furthermore, an intermediate joint is arranged between the first main shaft and the punching bearing seat, and the intermediate joint enables the first main shaft and the punching bearing seat to be synchronously connected in a threaded connection mode.

Furthermore, an interval space is formed between the end face of the middle joint connected with the punching bearing seat and the vibration sleeve arranged on the punching bearing seat, and a spring is installed in the interval space.

Furthermore, the outer walls of the vibration sleeve and the impact head are respectively provided with a steel ball, the steel balls are used for supporting the vibration sleeve and the impact head, a second shell is further arranged on the periphery of the steel balls, and one end of the second shell is in threaded connection with the intermediate joint.

Further, a PDC bearing moving ring, a PDC bearing static ring, a lower TC moving ring, a lower TC static ring and a lower joint are sequentially sleeved on the joint of the bearing impact seat and the second spindle, the PDC bearing static ring is forbidden to be kept, and the PDC bearing moving ring and the second spindle rotate together.

Further, a TC radial bearing and a rolling ball bearing which are used for supporting the first main shaft are installed on the outer side of the first main shaft from top to bottom, and the TC radial bearing and the rolling ball bearing are in locking connection through a main shaft locking nut.

Furthermore, the rolling ball bearing consists of an inner ring, an outer ring and a steel ball, and the inner ring and the outer ring of the bearing are provided with arc raceways.

Further, a first outer shell is further arranged on the peripheries of the TC radial bearing and the rolling ball shaft, and the first outer shell is connected with the middle joint through threads; and (3) carrying out quenching and tempering treatment on the first outer shell, the middle joint and the second outer shell, wherein the hardness HB is 250-.

Furthermore, the vibration starting seat is a displacement bearing consisting of an upper vibration starting body and a lower vibration starting body, and the steel ball groove pitch circle expansion lines of the upper vibration starting body and the lower vibration starting body of the vibration starting seat have four structures of sine or cosine harmonic groove shape, sawtooth groove shape, rectangular groove shape and triangular groove shape.

Furthermore, a nozzle is further arranged at one end, close to the first main shaft, of the impact bearing seat, and the nozzle is used for assisting the jet flow speed effect and realizing the automatic pushing function.

The method for generating the impact of the drilling tool comprises the steps that the vibration starting seat generates axial displacement and transmits the axial displacement to the drilling tool to generate the impact; the upper vibration starting body is contacted with the vibration sleeve; the lower vibration generator is contacted with the connecting sleeve.

The upper oscillator is provided with a groove, and the groove pitch circle expansion line has four groove shapes of sine or cosine harmonic groove shape, sawtooth groove shape, rectangular groove shape and triangular groove shape.

The lower vibration starting body is provided with a uniform groove, two steel balls are embedded in the groove, and the relative positions of the steel balls are ensured by a retainer.

When the lower oscillator body rotates relative to the upper oscillator body, the small balls in the lower oscillator body move in the uneven grooves of the upper oscillator body, which is equivalent to the fact that the small balls move on the irregular surface to generate displacement perpendicular to the irregular surface (the small balls generate axial displacement); when the small ball in the lower vibration generator moves towards the raised area of the groove of the upper vibration generator, the small ball and the surface of the groove of the upper vibration generator extrude the vibration generating seat to generate axial displacement, and the spring is lengthened to store energy. The axial displacement can be transmitted to the impact head through the connecting sleeve, the impact head can impact the impact bearing seat, and finally the impact is transmitted to the drilling tool. When the small ball in the lower vibration starting body moves towards the concave area of the groove of the upper vibration starting body, the spring pulls the upper vibration starting body and the lower vibration starting body to release energy because the extrusion force between the small ball and the groove surface disappears. And simultaneously, the impact head, the impact seat and the drilling tool are pulled back to the original positions, and the impact process is completed once.

The beneficial effect that adopts this technical scheme to reach does:

1. the tool is powered by a turbine motor, a screw motor or an electric motor and the like, has good high-temperature resistance, and cannot cause centrifugal inertia force and transverse vibration;

2. the tool can apply a low-amplitude high-frequency torsional impact force to the drill bit, so that the stick-slip phenomenon of the drill bit is reduced, and the mechanical drilling speed is greatly improved;

3. by periodically providing the torsional impact force for the drill bit, the torsional impact force can be stably transmitted to the drill bit, the possibility of drill bit failure caused by drill sticking is reduced, the tripping and operating cost is reduced, and the comprehensive technical and economic benefits are improved.

4. The method can comprehensively solve the difficult problem of drilling the hard rock in the petroleum drilling, effectively improve the drilling speed of the hard rock, prevent the drilling deviation problem in the drilling of the hard rock layer and the complex stratum, reduce the drilling cost and realize the bottom hole pressurization of the horizontal well and the extended reach well.

5. The rock is crushed by the combined action of high-frequency periodic impact force and static pressure rotation.

Drawings

FIG. 1 is a schematic view of the upper structure of a down-hole displacement type percussion drill according to the present invention.

FIG. 2 is a schematic view showing the lower structure of the displacement type percussion drill in the well according to the present invention.

FIG. 3 is a partial schematic view of an upper vibration-starting body ball groove of the vibration-starting seat.

Fig. 4 is a schematic cross-sectional view taken along line a-a in fig. 3, showing a cross-section of the upper vibrator.

Fig. 5 is a saw tooth schematic diagram of the upper vibration starting body ball groove pitch circle of the vibration starting seat with a rectangular groove structure.

FIG. 6 is a schematic structural view showing that the ball groove pitch circle expansion line of the upper vibration-starting body of the vibration-starting seat has a triangular groove shape.

FIG. 7 is a schematic structural diagram of an upper vibration-starting body ball groove pitch circle expansion line of the vibration-starting seat having a ramp groove shape.

FIG. 8 is a structural schematic diagram of the upper vibration-starting body ball groove pitch circle expansion line of the vibration-starting seat having a tooth-shaped groove shape.

Wherein: the device comprises an overflow sleeve 1, a first shell 2, a main shaft locking nut 3, a radial bearing 4TC, a rolling ball bearing 5, a first main shaft 6, a middle joint 7, a spline sleeve 8, a nozzle 9, a spring 10, a second shell 11, a vibration sleeve 12, a vibration starting seat 13, a connecting sleeve 14, an impact head 15, a bearing and impact seat 16, a separation sleeve 17, a bearing movable ring 18PDC, a bearing static ring 19, a bearing movable ring TC 20, a bearing static ring TC 21, a bearing static ring TC 22, a lower joint 23, a second main shaft 23, an elastic retainer ring-A for 31 holes and a steel ball 32.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

The embodiment aims at the technical problems that in the prior art, only a rotary rock breaking mode is easy to cause drilling tool damage and cost investment is large, and designs the underground displacement impact type drilling tool which has the characteristics of compact structure and high energy density; the bottom pressurization of the horizontal well and the extended reach well can be realized, and the high-frequency periodic impact force and the static pressure rotation combined action are generated to crush the rock. Therefore, the difficult problem of drilling hard rock in petroleum drilling is comprehensively solved, and the drilling deviation condition in drilling of hard rock layers and complex strata is prevented; and the purposes of prolonging the service life of the drill bit and reducing the damage of the drilling tool so as to reduce the drilling cost are achieved.

Specifically, referring to fig. 1-2, the downhole displacement percussion drill comprises a flow-through sleeve 1, a first main shaft 6, a thrust bearing seat 16 and a second main shaft 23, which are all formed by annular structures and sequentially connected from top to bottom, wherein the annular structures are arranged among the first main shaft 6, the thrust bearing seat 16 and the second main shaft 23 and are used for conveying slurry flowing in from the flow-through sleeve 1; the outer wall of the impact bearing seat 16 is sequentially connected with a vibrating sleeve 12, an oscillation starting seat 13 and an impact head 15 from top to bottom, and the vibrating sleeve 12 and the impact head 15 are fixedly connected through a connecting sleeve 14; the vibration starting seat 13 is connected with the impact bearing seat 16 in a spline mode to synchronously rotate, and the vibration starting seat 13 generates axial up-and-down periodic displacement in the rotating process.

It can be understood that: the drilling tool breaks rock by using two modes of rotation energy and impact energy.

The rotational energy of the downhole power motor is connected with a power output shaft of the downhole power motor (not shown) through the flow sleeve 1 and the first main shaft 6, so as to form a power input and provide mechanical energy for the rotational motion, and optionally, the downhole power motor for providing power can comprise a turbine motor, a screw motor or an electric motor.

The impact energy is generated by the vibration starting seat 13 on the second main shaft 23; the vibration starting seat 13 generates a periodically-changed axial displacement along with the rotation of the second main shaft 23, i.e. an original basis of impact is formed; the frequency of the displacement is saw-toothed or harmonic. A spring 10 (described later) for generating an impact force in the axial direction; the lower end of the second main shaft 23 is connected with a drill bit, so that the drill bit displacement impact motion is provided, and an impact type mechanical energy output is formed.

The well drilling tool utilizes the combined work of the underground power motor and the drill bit, so that the drill bit can carry out rock breaking in two modes of rotation and displacement impact, the drill bit is protected, and the well drilling speed is increased.

The construction of the displacement percussion drill in the well will be described in detail below.

The underground displacement type percussion drill mainly comprises an overflow sleeve 1, a first shell 2, a main shaft locking nut 3, a TC radial bearing 4, a rolling ball bearing 5, a first main shaft 6, a middle joint 7, a spline sleeve 8, a nozzle 9, a spring 10, a second shell 11, a vibrating sleeve 12, a vibration starting seat 13, a connecting sleeve 14, an impact head 15, a bearing impact seat 16, a separating sleeve 17, a PDC bearing moving ring 18, a PDC bearing static ring 19, a lower TC moving ring 20, a lower TC static ring 21, a lower joint 22, a second main shaft 23, a hole elastic check ring-A type 31 and a steel ball 32.

Wherein the flow sleeve 1 is used for receiving slurry flowing in from a downhole power motor (not shown); the lower end of the flow sleeve 1 is connected with the first main shaft 6 through a thread form, and the upper end of the flow sleeve 1 is connected with the downhole power motor through a thread form, wherein the downhole power motor can comprise a turbine motor, a screw motor or an electric motor.

The TC radial bearing 4 and the rolling ball bearing 5 are arranged on the first main shaft 6 and used for supporting; the spindle lock nut 3 is used to lock the TC radial bearing 4 and the rolling ball bearing 5 mounted on the first spindle 6.

Optionally, the surface of the TC radial bearing 4 is plated with hard alloy, that is, the inner and outer surfaces of the bearing are regularly plated with hard alloy blocks, special-component solder, hard alloy and other additives, and the additives and the basic member are fused into a whole through special sintering treatment.

In the embodiment, the rolling ball bearing 5 consists of an inner ring, an outer ring and a steel ball, and the inner ring and the outer ring of the rolling ball bearing 5 are provided with arc raceways; 5-13 pairs of rolling ball bearings 5 form a group; the rolling ball bearing 5 can bear larger axial load, has compact integral structure and small occupied space, and can bear bidirectional load; when the device works, the rolling ball bearing 5 is lubricated by using slurry, so that the abrasion of the multi-stage ball bearing is reduced; the mud is mainly transmitted to the drill bit through the main shaft, and the axial direction of the main shaft is within a certain allowable clearance.

The first shell 2, the middle joint 7 and the second shell 11 are connected together in a threaded mode; and the first housing 2 is connected on the upper side to the downhole power motor described above.

In this embodiment, the first housing 2, the intermediate joint 7, and the second housing 11 are subjected to quenching and tempering, and then subjected to blackening treatment, wherein the hardness HB is 250-; the housings (first housing 2, second housing 11) are here provided to achieve axial and radial positioning of the inner parts and to ensure that the inner parts can withstand deflection and longitudinal bending due to axial loads and transverse stresses.

In this embodiment, the casing (the first casing 2 and/or the second casing 11) may be provided with a blade, which is equivalent to a stabilizer, so as to meet the requirement of preventing well deviation when drilling a vertical well, and to control the well track when drilling a directional well, thereby improving the working stability of the drill bit and prolonging the service life of the drill bit.

A spacing space is formed between the end face of the intermediate joint 7 connected with the punch bearing seat 16 and the vibrating sleeve 12 arranged on the punch bearing seat 16, the spring 10 is arranged in the spacing space, and the spring 10 stores and releases energy through continuous extension and compression; it can be understood that the intermediate connector 7 and the vibration sleeve 12 are elastically connected through the spring 10, and the vibration sleeve 12, the connecting sleeve 14 and the impact head 15 are installed along the axial direction of the impact socket 16 and can transmit the impact generated by the spring 10.

The above-mentioned steel balls 32 are respectively mounted outside the vibration housing 12 and the impact head 15 for supporting the vibration housing 12 and the impact head 15.

It can be understood that the vibrating sleeve 12 and the punch bearing seat 16 are connected together and can rotate together with the punch bearing seat 16; the connecting sleeve 14 is fixedly connected with the vibrating sleeve 12, and the vibrating sleeve 12 transmits impact force to the impact head 15 through the connecting sleeve 14; the impact head 15 generates impact on the impact bearing seat 16; the outside of the impact head 15 is provided with a steel ball 32 for supporting the impact head 15; the impact socket 16 transmits the rotary motion to the second spindle 23 in the form of a spline sleeve and further to the drill bit in the form of drill bit rotation.

Optionally, the PDC bearing moving ring 18 and the PDC bearing stationary ring 19 are sleeved on the impact bearing base 16, the PDC bearing moving ring 18 and the PDC bearing stationary ring 19 are mounted on the impact bearing base 16 and can slide relative to each other, and the PDC bearing moving ring 18 and the PDC bearing stationary ring 19 are used for supporting the impact bearing base 16; the PDC bearing moving ring 18 and the second main shaft 23 rotate together, and the PDC bearing static ring 19 keeps static; the lower joint 22 effects a seal against the second main shaft 23.

In the present embodiment, referring to fig. 3 to 8, the vibration starting seat 13 is connected with the second main shaft 23 through a key; the vibration starting seat 13 is a displacement bearing consisting of an upper vibration starting body and a lower vibration starting body, is made of 55SiMoVA, has heat treatment hardness of HRC54-57, and is subjected to nondestructive flaw detection and acid pickling inspection after coarse grinding and then is subjected to tempering treatment; the vibration starting seat 13 consists of an upper vibration starting body and a lower vibration starting body and can generate axial displacement; the steel ball groove pitch circle expansion lines of the upper vibration starting body and the lower vibration starting body of the vibration starting seat 13 have four structures of sine or cosine harmonic groove shape, sawtooth groove shape, rectangular groove shape, triangular groove shape and the like, and the number of each groove corresponding to the four structures can be changed and can be 2, 3, 4, 5, 6 or more.

The end of the impact bearing seat 16 close to the first main shaft 6 is also provided with a nozzle 9, the nozzle 9 plays a role in automatically pushing the whole drilling tool, and simultaneously can improve the auxiliary jet effect of the drill bit and greatly improve the impact force of the jet on the well bottom under the condition of not increasing the power of a surface pump.

The following explains the specific operation:

when a downhole power motor (a turbine motor, a screw motor, an electric motor or the like) rotates, the first main shaft 6, the flushing bearing seat 16 and the second main shaft 23 are driven to rotate through the overflowing sleeve 1, and a drill bit connected with the second main shaft 23 applies pressure to a stratum, so that rock is crushed. Meanwhile, the vibration starting seat 13 rotates together with the second main shaft 23 and the punch bearing seat 16 under the connection action of the spline. At this time, the vibration starting seat 13 generates axial displacement in the rotation process, and drives the punch bearing seat 16 to move up and down periodically in the axial direction.

When the axial displacement of the vibration starting seat 13 increases, the displacement is transmitted to the connecting sleeve 14, and the connecting sleeve 14 moves in the axial direction, so that the vibration sleeve 12 is driven to move in the axial direction. The vibration housing 12 compresses the spring 10, enabling the spring 10 to store reservoir energy while the punch holder 16 and the spline housing are more tightly connected.

When the axial displacement of the vibration starting seat 13 is reduced, the impact bearing seat 16 is driven to move downwards on the axis, and the energy of the reservoir in the spring 10 is continuously released. Since the radial displacement speed of the balls in the vibration starting seat 13 is not uniform, the spring is not uniformly stretched in the released energy, and periodic impact is generated on the vibration sleeve 12.

The vibrating sleeve 12 transmits impact force to the impact head 15 through the connecting sleeve 14, then the impact head 15 generates impact on the impact bearing seat 16 again, and the impact bearing seat 16 transmits the impact force to the drill bit, so that the impact force of the drill bit on the rock layer changes periodically.

Of course, during drilling, a part of the slurry moves along the axial direction of the overflowing sleeve 1, the first main shaft 6, the flushing bearing seat 16 and the second main shaft 23 to drive the drill bit to crush rocks, the other part of the slurry lubricates the TC radial bearing 4 and the rolling ball bearing 5, and a part of the slurry directly impacts the vibrating sleeve 12 together with the spring 10 and can lubricate the steel ball 32.

The connecting thread of the overflowing sleeve 1 and the first main shaft 6 is provided with an observation hole for observing whether the thread is in place during screwing in during assembly; the spindle lock nut 3 serves to limit the position of the TC radial bearing 4 and the rolling ball bearing 5 on the first spindle 6. The upper part of the first housing 2 is used for connecting a motor housing in the form of a turbine motor, a screw motor or an electric motor. The first housing 2, the intermediate joint 7, the second housing 11 are used for axially and radially positioning the drill, are capable of withstanding flexing and longitudinal bending due to axial loads and transverse stresses, are drilled and bored from high quality forged steel bar stock, heat treated and finish ground in the inner bore.

The mountable blade on first shell 2 is equivalent to the effect of stabilizer, can satisfy the requirement that prevents the well deviation when drilling straight well, can play the effect of control well orbit when drilling directional well, can also improve the stability of drill bit work to extension drill bit life.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.