CN204266924U - A kind of PDC bit tool with alternation Cutting trajectory - Google Patents

Abstract

The utility model discloses a PDC drill bit tool with alternating cutting tracks, which belongs to the field of rock-breaking tools for drilling equipment. The PDC drill tool with alternating cutting trajectory of the utility model includes an eccentric shaft, an outer shell, a PDC drill bit and a cycloidal shaft, the PDC drill bit is fixedly connected to the cycloidal shaft, and the cycloidal shaft is matched in the outer shell body so that the trajectory can be changed relatively. Eccentric rotation, the eccentric shaft section provided on the eccentric shaft is matched with the inner cavity of the cycloid shaft to form a rotating pair, the inner flow channel of the eccentric shaft, the inner flow channel of the cycloid shaft communicate with the inner flow channel of the PDC drill bit. The alternating cutting trajectory movement realized by the utility model can significantly improve the ability of the PDC bit to penetrate into the formation, improve the rock-breaking efficiency, and is also beneficial to slow down the wear speed of the cutting teeth, especially in the deep hard-drilled formation with high hardness and high abrasiveness. Obvious technical advantage.

Description

A PDC Drill Tool with Alternating Cutting Trajectories

technical field

The utility model relates to the field of rock-breaking tools for drilling equipment such as petroleum and natural gas, mining engineering, building foundation engineering construction, geology, and hydrology, in particular to a PDC bit tool for rock-breaking for drilling equipment.

Background technique

The drill bit is a rock-breaking tool used in drilling engineering to break the rock at the bottom of the well and form a wellbore. The conventional drill bits used in drilling engineering today mainly include three-cone bits, PDC bits, impregnated diamond bits, and roller-PDC hybrid bits.

Among them, PDC drill bit (polycrystalline diamond compact drill bit) is the most commonly used drilling tool in oil drilling engineering. With the continuous advancement of cutting tooth material technology and bit design technology, its unique drilling safety, structural flexibility and efficient cutting performance for shearing and breaking rock make the PDC bit more suitable for formation in oil and gas drilling engineering. More widely, according to statistics, 70% of the total drilling footage in the world is completed by PDC bits, which occupies an absolutely important position. The conventional PDC bit mainly breaks the rock at the bottom of the well through the action of "eating-scraping". However, when drilling encounters hard plastic formations, it is often difficult for the cutting teeth on the PDC bit to effectively eat the rock at the bottom of the well. Will become very slow and difficult to get good drill usage.

In order to cope with this situation, Chinese patent CN 200880016630.0 discloses a "hybrid drill bit", which has a composite cutting structure with rolling cones and fixed blades, which can crush the impact of the cones and the rock-breaking method and the scraping of the blades. The combination of rock-cutting methods can obtain better comprehensive drilling effect under specific formation conditions. However, the shortcomings of this drill bit are mainly manifested in: the impact load generated by the rock breaking of the cone is likely to cause abnormal failure of the diamond teeth on the fixed blade, such as chipping, delamination, broken teeth or tooth loss, etc., which hinders the efficient application of the drill bit. bring about uncertainties. Chinese patent CN 201010229371.9 discloses "a composite drill bit for breaking rock by cutting", which uses the idea of "breaking rock in the form of alternate scraping can improve the efficiency of rock breaking", and proposes a kind of drill bit equipped with PDC teeth. Composite drill bit with high-strength cutting wheels and fixed blades arranged alternately. The "rotary wheel-fixed blade" composite cutting structure of the drill bit can form a mesh crushing area on the rock at the bottom of the well, which has the advantages of high rock breaking efficiency, uniform wear, and long service life of the drill bit. The runner described in the drill bit is a passive rotary cutting structure, which realizes "slow alternate cutting process" under the reaction force condition of formation rock. However, there are many factors that affect the rotary motion of the runner, such as the rock morphology and mechanical properties of the formation, the matching relationship between the cutting structure of the wheel body and the fixed cutting structure, drilling parameters, and the friction between the wheel body and the bearing or journal, etc. There is uncertainty in the law of rotational motion. When under some special working conditions, the direction of the comprehensive driving force of the wheel body may be perpendicular to the direction of the rotational linear velocity of the wheel body, that is, the dead point working condition, the wheel body will be "stuck" and does not move. At this time, the drill bit will not be able to achieve the effect of "breaking rock in the form of alternate scraping and cutting".

Utility model content

The purpose of the invention of the present utility model is to provide a PDC drill bit tool with alternating cutting tracks in view of the above-mentioned problems, combining a downhole transmission mechanism capable of producing eccentric swing rotation with the PDC drill bit, through which the downhole transmission mechanism The compound movement with the drill string system can provide an alternating cutting motion track movement for the PDC bit. First, it can form a mesh cross cutting process on the bottom of the well, increase the ability of the cutting teeth of the drill bit to penetrate rock, and improve rock breaking. The second is to change the "cutting" rock breaking to "alternate plowing" rock breaking, which can improve the self-sharpening and attacking ability of the drill bit, which is conducive to improving the rock breaking efficiency; third, the alternating track cutting motion of the drill bit has "forced ", high reliability. It has obvious technical advantages especially in deep hard-to-drill formations with high hardness and high abrasiveness.

The technical scheme that the utility model adopts is as follows:

The PDC drill tool with alternating cutting trajectory of the utility model includes an eccentric shaft, an outer shell, a PDC drill bit and a cycloidal shaft. The PDC drill bit is fixedly connected to the cycloidal shaft, and the cycloidal shaft is matched in the outer shell body so that the trajectory can be changed relatively. Eccentric rotation, the eccentric shaft section provided on the eccentric shaft is matched with the inner cavity of the cycloid shaft to form a rotating pair, the inner flow channel of the eccentric shaft, the inner flow channel of the cycloid shaft communicate with the inner flow channel of the PDC drill bit.

Due to the adoption of the above structure, the eccentric shaft section on the eccentric shaft matches the cycloid shaft to form a revolving pair, so that when the eccentric shaft rotates, the eccentric shaft section drives the cycloid shaft to perform eccentric rotation with variable trajectory relative to the outer shell, thereby driving the PDC bit to perform alternate cutting The movement trajectory, first, can form a mesh cross cutting process on the bottom of the well, increase the ability of the cutting teeth of the drill bit to penetrate the rock, and improve the rock breaking efficiency; second, change the "cutting" rock breaking to "alternate plowing" rock breaking , can improve the self-sharpening and attack ability of the drill bit, and is beneficial to slow down the wear speed of the cutting teeth; third, the alternating track cutting motion of the drill bit is "mandatory" and has high reliability. It has obvious technical advantages especially in deep hard-to-drill formations with high hardness and high abrasiveness. Specifically: 1. The cutting motion of the alternating trajectory can effectively improve the rock-breaking drilling efficiency of the drill bit. The trajectory of the conventional fixed cutter PDC bit at the bottom of the well is circular, and each tooth performs scraping motion along its fixed rotation trajectory, whether it is the drilling and failure of the drill bit in the field, or the drillability experiment in the room. It can be reflected that the formation penetration ability of the PDC drill bit in this motion state affects the rock-breaking efficiency of the drill bit, especially in deep difficult-to-drill formations, and this impact is more serious. However, this patent can realize the cutting motion of the net-like alternating track at the bottom of the well, which is beneficial to the effective penetration of the rock by the cutting teeth and the crushing of the rock, thereby effectively improving the rock-breaking efficiency of the drill bit. 2. Changing "cutting" rock breaking to "alternate plowing" rock breaking can improve the self-sharpening and attacking ability of the drill bit. When the conventional fixed-tooth PDC bit performs circular trajectory cutting motion at the bottom of the well, the cutting line speed direction and the normal direction of the working plane are fixed (relatively unchanged), that is, the working rake angle and edge inclination angle of the cutting teeth are fixed. . In general, the working rake angle of conventional drills is equivalent to the rake angle of the cutting structure (30°-10°), and the blade inclination angle is relatively small (generally within 5°). It is in the state of "negative rake angle bottom edge cutting". When the cutting teeth of the PDC bit perform alternating trajectory cutting motion, the blade inclination angle of the cutting teeth changes all the time during the movement (changes according to the law of sinusoidal curve). When the blade inclination angle is large to a certain extent, the contact motion state between the cutting teeth and the rock at the bottom of the well becomes "plowing" contact. This change in cutting state can effectively improve the aggressiveness of the drill bit, thereby improving the rock-breaking efficiency of the drill bit. At the same time, the change of the blade inclination angle is bidirectional, that is, changing the cutting of the bottom edge of the conventional cutting tooth to the left and right alternate double-edged cutting of the cutting tooth under the condition of alternating trajectory movement, the effect is to increase the wear resistance of the cutting tooth at the same time. The special self-sharpening ability of the cutting teeth improves the working performance of the drill bit. 3. The alternating track cutting motion of the drill bit is mandatory. Whether it is a cone-PDC composite drill bit or a wheel-type composite diamond drill bit, it is a combination of fixed tooth cutting structure and wheel body rotating cutting structure. The rotation of the wheel body is driven by the reaction force with the formation rock, which is passive. Rotational movement. There are many factors that affect the rotation of the wheel, such as the formation rock morphology and mechanical properties, the matching relationship between the cutting structure of the wheel and the fixed cutting structure, the drilling parameters and the friction between the wheel and the bearing or the journal, etc., so the rotation of the wheel There is uncertainty in the laws of motion. When under some special working conditions, the rotational comprehensive driving force direction of the wheel body may be perpendicular to the rotation linear velocity direction of the wheel body, that is, the dead point working condition, the wheel body will be "stuck" at this time. It is often observed in indoor experiments that the wheel body cannot rotate. In the structural scheme proposed by the utility model, the non-circular curve rotation motion power of the PDC bit comes from the inside of the tool, and the interaction force with the formation rock has little effect on its motion law, so it can ensure that the PDC bit realizes regular "interaction" Variable trajectory cutting motion", its working reliability is significantly improved. The well fluid circulation in the utility model is that the drilling fluid fluid in the drill string system passes through the inner channel of the eccentric shaft and the inner channel of the cycloid shaft, and then enters the downhole annular space through the inner flow channel and the nozzle of the PDC bit, and then establishes the drilling fluid circulation system. Make sure that the PDC bit is filled with mud while producing alternate cutting trajectories, so as to ensure the normal drilling of the PDC bit.

In the PDC drill bit tool with alternating cutting tracks of the utility model, a number of needle teeth groups are evenly distributed on the inner wall of the outer casing to form a needle wheel structure, and a number of cycloid teeth are arranged on the outer wall of the cycloid shaft. The gear teeth are meshed with the pin wheel structure to form a meshing transmission relationship; or the inner wall of the outer shell is evenly distributed with a number of gear teeth, and the outer wall of the cycloid shaft is provided with a number of cycloid teeth, and the cycloid teeth and the gear teeth The meshing constitutes a meshing transmission relationship.

Due to the adoption of the above structure, a mechanism that cooperates with the cycloid shaft is provided in the housing, such as a gear tooth structure that matches the cycloid teeth outside the cycloid shaft, or a pin wheel structure, so that the utility model forms an alternating rotation when driving the PDC drill bit. When cutting the trajectory, the torque transmission is generated by the joint action of two transmission methods. One is that the rotational torque of the drill string system is directly transmitted to the outer shell through the connecting thread, and then transmitted through the gear pair of the pin tooth set and the cycloid tooth on it. To the cycloid shaft, and then transmitted to the PDC bit through the connecting thread; secondly, the torque output by the downhole dynamic drilling tool (such as screw drilling tool, turbo drilling tool, etc.) is transmitted to the eccentric shaft through the connecting thread, and then through the outer cylinder of the eccentric shaft section. The rotation pair formed by the surface and the cycloid teeth and the pin tooth group and the cycloid gear pair are transmitted to the cycloid shaft, and then transmitted to the PDC drill bit through the connecting thread; several pin tooth groups are arranged on the inner wall of the outer shell The formed pin wheel structure can be formed similar to the ring gear structure, and the gap between any two adjacent pin tooth groups can be meshed with the cycloid shaft, and the number of pin tooth groups and the number of cycloid teeth can be adjusted according to In fact, it is necessary to find the power transmission ratio to facilitate the matching and transmission of power torque.

In the PDC drill bit tool with alternating cutting tracks of the utility model, the needle wheel structure includes several needle tooth seats with different axial heights arranged on the inner wall of the housing, and the needle tooth seats are equipped with needle tooth groups, so that The axial heights of each group of pin tooth seats are the same, wherein the pin tooth sets include pin tooth pins fitted on the pin tooth seats, and pin tooth sleeves are sheathed on the pin tooth pins.

Due to the adoption of the above structure, there are at least two groups of gear holders with different axial heights on the inner cylindrical surface of the outer shell. The needle holders are matched with the needle pins. Evenly arranged in the circumferential direction, so as to ensure that the height of the pin wheel structure formed by cooperation is consistent, and can mesh with the cycloid shaft, so that when the eccentric shaft drives the cycloid shaft to perform eccentric rotation with variable trajectory, the cycloid teeth outside the cycloid shaft can It fits with the pin tooth sleeve on the pin tooth pin and rotates along the direction of the pin tooth set to ensure that the cycloid shaft can normally perform eccentric rotation with variable trajectory.

In the PDC drill bit tool with alternating cutting tracks of the utility model, the eccentric shaft is threadedly connected to the output end of the downhole power drilling tool, and the outer casing is threadedly connected to the end of the drill string system.

Due to the adoption of the above structure, connecting the connecting thread on the eccentric shaft with the output end of the lower power drilling tool (such as screw drilling tool, turbo drilling tool, etc.) of the drill string system in oil drilling can provide the eccentric shaft with its rotation power, while ensuring relative rotation between the eccentric shaft and the outer shell. The torque transmission in the utility model is produced by the joint action of two transmission modes, one is that the rotational torque of the drill string system is directly transmitted to the outer casing through the connecting thread, and then through the gear pair of the pin tooth group and the cycloid tooth on it It is transmitted to the cycloid shaft, and then transmitted to the PDC bit through the connecting thread; the second is that the torque output by the downhole power drilling tool (such as screw drill, turbo drill, etc.) is transmitted to the eccentric shaft through the connecting thread, and then through the outer part of the eccentric The rotary pair formed by the cylindrical surface and the lower end surface of the positioning shaft shoulder and the pin tooth group and the gear pair of the cycloidal teeth are transmitted to the cycloidal shaft under the joint action, and then transmitted to the PDC bit through the connecting thread.

In the PDC drill bit tool with alternating cutting tracks of the present utility model, in the meshing transmission relationship, the transmission ratio formed by the eccentric shaft and the cycloid shaft is ≥7:1, and the eccentric distance e of the eccentric shaft section on the eccentric shaft is ≤6mm.

Due to the adoption of the above structure, the PDC bit can be cut by reasonably matching the geometric parameters (number of cycloidal shaft teeth, pin tooth number, eccentricity, etc.) The tooth obtains a more regular bottom-hole alternate cutting motion track. It is this characteristic that enables the PDC bit to provide an alternate cutting motion track. The cutting ability can improve the rock breaking efficiency; the second is to change the "cutting" rock breaking to "alternate plowing" rock breaking, which can improve the self-sharpening and attacking ability of the drill bit; Mandatory", high reliability. The alternating cutting track movement realized by the utility model can significantly improve the ability of the PDC bit to penetrate into the formation, improve the rock-breaking efficiency, and is also beneficial to slow down the wear speed of the cutting teeth, especially in deep hard-drilled formations with high hardness and high abrasiveness. Obvious technical advantage.

In the PDC drill bit tool with alternating cutting tracks of the utility model, in the meshing transmission relationship, the transmission ratio formed by the eccentric shaft and the cycloid shaft is 7, and the eccentric distance e of the eccentric shaft section on the eccentric shaft is 6mm .

Due to the adoption of the above structure, the preferred geometric parameters in the utility model are: cycloid axis, number of teeth is 7, needle tooth group, number of teeth is 8, and when eccentricity e is 6, it is assumed that the speed of downhole power drilling tool is 140 rev/min , when the rotation speed of the drill string system is 0 rpm, the single tooth on the PDC bit can realize the motion trajectory shown in Figure 18; assuming that the rotation speed of the downhole power drilling tool is 120 rpm, and the rotation speed of the drill string system is 40 rpm /min (transmission ratio i=3), a single tooth on the PDC bit can realize the motion trajectory shown in Figure 19; assuming that the downhole power drilling tool rotates at 120 rpm, and the drill string system rotates at 60 rpm When (transmission ratio i=2), a single tooth on the PDC bit can realize the motion trajectory shown in Figure 20; assuming that the geometric parameter eccentricity e is changed to 12, and the kinematic parameter downhole motor speed is 120 rpm/ When the rotation speed of the drill string system is 60 rpm (transmission ratio i=2), a single tooth on the PDC bit can realize the motion trajectory shown in Figure 21.

In the PDC drill tool with alternating cutting tracks of the utility model, the lower joint connected to the outer shell limits the cycloid shaft in the outer shell, the lower joint is provided with an eccentric bearing, and the PDC drill bit passes through the lower joint The eccentric bearing is screwed to the lower end of the cycloid shaft; the eccentric shaft is provided with an eccentric shaft section and a positioning shoulder, wherein a centripetal thrust bearing group is arranged between the eccentric shaft section and the inner cavity of the cycloid shaft, and the eccentric A sealing ring is arranged between the lower end surface of the shaft and the cycloid shaft for sealing, and a radial bearing is arranged between the positioning shoulder and the outer casing.

Due to the adoption of the above structure, an eccentric bearing is installed between the PDC bit and the lower joint. The eccentric bearing can be a needle roller eccentric bearing, a sliding bearing, or a cylindrical roller bearing or a double row tapered roller bearing, or an adjustable With the center roller bearing, the PDC bit is a cantilever structure in the state of variable trajectory eccentric rotation, and its structural rigidity and mechanical stability are lower than those of the conventional PDC bit. Moreover, the addition of eccentric bearings can make the "eccentric wheel-PDC bit" mechanism into a double support structure, thereby improving the structural rigidity and mechanical stability, and achieving a better use effect. A radial bearing is installed between the shoulder of the eccentric shaft and the inner surface of the casing. In particular, the thrust bearing set is a combination of not less than two TC-type radial thrust bearings consisting of bearing inner rings, bearing outer rings and rolling elements; the radial bearings are needle roller bearings or sliding bearings or rolling-sliding composite bearings. Due to the eccentric rotation of the variable trajectory of the PDC bit, the eccentric shaft and the cycloid bearing are subjected to a large radial asymmetric force, and the drilling pressure of the PDC bit needs to be transmitted from the eccentric shaft to the cycloid shaft and then to the PDC bit. Therefore, between the eccentric shaft and the outer shell, and between the eccentric shaft and the cycloid shaft, a large contact friction force will be generated. In order to slow down the influence of this contact friction force on the friction and wear of the mechanical structure described in this embodiment, a thrust bearing set and Radial bearings are used to improve the working stability and prolong the service life of this embodiment.

In the PDC drill bit tool with alternating cutting tracks of the utility model, a floating sealing structure is provided between the PDC bit and the lower joint, and the floating sealing structure includes a floating ring, a sealing gland and a sealing ring, wherein the floating Sealing rings are arranged on the axial and radial planes of the ring to form a seal between the PDC bit and the lower joint, the sealing gland is connected to the lower joint, and the floating ring is located between the sealing gland and the lower joint , and can rotate eccentrically with the track of the PDC bit in the cavity between the lower joint and the sealing gland.

Due to the adoption of the above structure, sealing rings are provided on the axial and radial planes of the floating ring to realize the sealing between the PDC drill bit and the lower sub The eccentric rotation with variable trajectory in the cavity can realize the "floating seal", so as to ensure that the relative eccentric rotation with variable trajectory can occur between the PDC bit and the lower joint, and it can also form a dynamic seal to ensure the sealing effect. On the one hand, the utility model should have ideal lubrication conditions, and on the other hand, it should try to prevent the hard particles in the external drilling fluid from entering the moving pair surface to cause abrasive wear. Therefore, in order to improve the practicability and reliability of this embodiment, It is very necessary to set up a sealing mechanism.

In the PDC drill tool with alternating cutting tracks of the utility model, a number of gages are uniformly distributed on the outer wall of the outer shell, and the upper surface of the gages is provided with a number of passive wear-resistant teeth and/or active gages teeth; the PDC bit is provided with several blade structures, and several PDC teeth are arranged on the blade structures.

Due to the adoption of the above structure, the outer cylindrical surface of the outer shell is provided with gage corrugations, which can be in the form of straight strips or spiral structures, and the number of gage corrugations is two or more. The PDC bit performs alternating track cutting motion, and the cutting amount and cutting load of the cutting teeth on it are always changing in one revolution cycle, so it has a great impact on the overall mechanical stability of the PDC bit, so the gauge structure is strengthened The wear resistance and diameter keeping ability are particularly important. In this case, the solution proposed by the utility model can effectively reduce the negative impact on the overall drilling effect of the PDC bit due to the cutting motion of the cutting teeth in alternating tracks. On the one hand, the passive anti-friction teeth can effectively reduce the excessive wear on the gauge structure of the drill bit due to the high lateral unbalance of the drill bit, and play a role in protecting the structure of the drill bit body. At the same time, the diameter gauge structure of the drill bit with high wear resistance can provide better righting and stability for the PDC bit, which is conducive to improving the drilling performance of the drill bit. On the other hand, the geometric outer diameter of the PDC bit in the utility model is smaller than the size of the drilled wellbore. Under the condition of the drill bit doing alternating track cutting motion, it is often difficult to meet the requirements of drilling only by the gauge teeth or gauge teeth on the bit body. Requirements for regular well walls during the process. Therefore, the introduction of active cutting teeth on the gage corrugation of the outer casing of the utility model can effectively improve the gage capacity of this embodiment, thereby improving the drilling quality and the drilling capacity of the drill bit. Among them, the so-called "active cutting tooth" in the utility model is defined as the fixing method of the cutting tooth on the gage block as "the angle between the normal line of the working surface of the cutting tooth and the radial line of the stabilizer at the point where the cutting tooth is located is relatively large. "In general, the angle is not less than 60°. In this case, the cutting teeth can eat and scrape the well wall with a negative rake angle to achieve the effect of active diameter protection; the so-called "passive wear-resistant teeth" are defined as the cutting teeth in the righting The fixing method on the block is "the angle between the normal line of the working surface of the cutting tooth and the radial line of the stabilizer at the point where the cutting tooth is located is small", and the angle is generally less than 10°. In this case, the cutting tooth can only be The friction and extrusion method of gage is called passive gage.

In summary, due to the adoption of the above technical solution, the beneficial effects of the utility model are:

1. Alternating trajectory cutting motion can effectively improve the rock-breaking drilling efficiency of the drill bit. The trajectory of the conventional fixed cutter PDC bit at the bottom of the well is circular, and each tooth performs scraping motion along its fixed rotation trajectory, whether it is the drilling and failure of the drill bit in the field, or the drillability experiment in the room. It can be reflected that the formation penetration ability of the PDC drill bit in this motion state affects the rock-breaking efficiency of the drill bit, especially in deep difficult-to-drill formations, and this impact is more serious. However, this patent can realize the cutting motion of the net-like alternating track at the bottom of the well, which is beneficial to the effective penetration of the rock by the cutting teeth and the crushing of the rock, thereby effectively improving the rock-breaking efficiency of the drill bit.

2. Changing "cutting" rock breaking to "alternating plowing" rock breaking can improve the self-sharpening and attacking ability of the drill bit. When the conventional fixed-tooth PDC bit performs circular trajectory cutting motion at the bottom of the well, the cutting line speed direction and the normal direction of the working plane are fixed (relatively unchanged), that is, the working rake angle and edge inclination angle of the cutting teeth are fixed. . In general, the working rake angle of conventional drills is equivalent to the rake angle of the cutting structure (30°-10°), and the blade inclination angle is relatively small (generally within 5°). It is in the state of "negative rake angle bottom edge cutting". When the cutting teeth of the PDC bit perform alternating trajectory cutting motion, the blade inclination angle of the cutting teeth changes all the time during the movement (changes according to the law of sinusoidal curve). When the blade inclination angle is large to a certain extent, the contact motion state between the cutting teeth and the rock at the bottom of the well becomes "plowing" contact. This change in cutting state can effectively improve the aggressiveness of the drill bit, thereby improving the rock-breaking efficiency of the drill bit. At the same time, the change of the blade inclination angle is bidirectional, that is, changing the cutting of the bottom edge of the conventional cutting tooth to the left and right alternate double-edged cutting of the cutting tooth under the condition of alternating trajectory movement, the effect is to increase the wear resistance of the cutting tooth at the same time. The special self-sharpening ability of the cutting teeth improves the working performance of the drill bit.

3. The cutting motion of the drill bit in alternating trajectory is mandatory. Whether it is a cone-PDC composite drill bit or a wheel-type composite diamond drill bit, it is a combination of fixed tooth cutting structure and wheel body rotating cutting structure. The rotation of the wheel body is driven by the reaction force with the formation rock, which is passive. Rotational movement. There are many factors that affect the rotation of the wheel, such as the formation rock morphology and mechanical properties, the matching relationship between the cutting structure of the wheel and the fixed cutting structure, the drilling parameters and the friction between the wheel and the bearing or the journal, etc., so the rotation of the wheel There is uncertainty in the laws of motion. When under some special working conditions, the rotational comprehensive driving force direction of the wheel body may be perpendicular to the rotation linear velocity direction of the wheel body, that is, the dead point working condition, the wheel body will be "stuck" at this time. It is often observed in indoor experiments that the wheel body cannot rotate. In the structural scheme proposed by the utility model, the non-circular curve rotation motion power of the PDC bit comes from the inside of the tool, and the interaction force with the formation rock has little effect on its motion law, so it can ensure that the PDC bit realizes regular "interaction" Variable trajectory cutting motion", its working reliability is significantly improved.

Description of drawings

The utility model will be explained by way of example and with reference to the accompanying drawings, wherein:

Fig. 1 is the three-dimensional assembly drawing of embodiment 1 in the utility model.

Fig. 2 is the structural composition figure of embodiment 1 in the utility model.

Fig. 3 is a schematic diagram of the connection structure between Embodiment 1 and the drill string system in the utility model.

Fig. 4 is a sectional view taken along line A-A of Fig. 1 .

Fig. 5 is a structural diagram of the eccentric shaft in Embodiment 1 of the present invention.

Fig. 6 is a structural diagram of the outer shell of Embodiment 1 of the present invention, the part shown in this figure is cut away to show its internal structure.

Fig. 7 is a structural diagram of the eccentric wheel in Embodiment 1 of the present invention, the part shown in this figure is cut away to show its internal structure.

Fig. 8 is a structural diagram of the lower joint in Embodiment 1 of the present invention.

Fig. 9 is a structural diagram of the PDC drill bit in Embodiment 1 of the present invention.

Fig. 10 is a three-dimensional assembly diagram of Embodiment 2 of the present invention.

Fig. 11 is a schematic diagram of the distribution structure of the needle and tooth seats on the inner cylindrical surface of the outer shell of the third embodiment of the present invention.

Fig. 12 is a structural composition diagram of Embodiment 4 of the present utility model.

Fig. 13 is an assembly diagram of Embodiment 5 of the present invention.

Fig. 14 is an assembly diagram of embodiment 6 of the present invention.

Fig. 15 is a partial view of No. I in the assembly drawing of Embodiment 6 in the utility model.

Fig. 16 is a partial view of No. II in the assembly drawing of Embodiment 6 of the present invention.

Fig. 17 is a schematic diagram of the movement of the mechanism in Embodiment 1 of the utility model.

Fig. 18 is a cutting tooth well bottom trajectory line in embodiment 1 of the present utility model.

Fig. 19 is the bottom hole trajectory of the second cutting tooth in embodiment 1 of the present invention.

Fig. 20 is the bottom hole trajectory of the third cutting tooth in embodiment 1 of the present invention.

Fig. 21 is the trajectory line of the bottom hole of the fourth cutter in embodiment 1 of the present utility model.

Fig. 22 is a schematic structural view of Embodiment 7 in the utility model;

Fig. 23 is a structural view of the outer casing in Embodiment 7 of the present invention, the part shown in this figure is cut away to show its internal structure.

Marks in the figure: 1-eccentric shaft; 2-outer shell; 3-PDC bit; 4-cycloidal shaft; 5-needle tooth set; 6-lower joint; 7-eccentric bearing; -end of drill string system; 10-central thrust bearing group; 11-connecting thread; 12-eccentric shaft section; 13-positioning shoulder; 15-radial bearing; 16-sealing ring; 17-floating seal structure; 17a -floating ring; 17b-seal gland; 17c-fastening bolt; 17d-sealing ring; 17e-spring washer; 24-needle seat; 25-shackle surface of the outer shell; 31-connecting thread of the PDC drill bit; 32-blade structure on the PDC drill bit; 33-PDC teeth on the blade structure; 41-cycloidal teeth; 42 -connecting thread of eccentric wheel; 43-swing profile line; 1a-outer cylindrical surface of positioning shaft shoulder; 1b-lower end surface of positioning shaft shoulder; 1c-outer cylindrical surface of eccentric shaft section; 1d-lower end surface of eccentric shaft , 4a-the upper end surface of the cycloid shaft; 4b-the inner cylindrical surface of the cycloid shaft; 4c-the inner end face of the cycloid shaft; 51-needle pin; 52-needle sleeve; 61-connecting thread of the lower joint; 6a-upper end face; 6b-lower end face; 211-passive wear-resistant teeth; 212-active gauge teeth.

Detailed ways

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification (including any appended claims, abstract), unless otherwise stated, may be replaced by alternative features that are equivalent or serve a similar purpose. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

Example 1:

As shown in Figures 1 to 9, the PDC drill tool with alternating cutting tracks of the utility model is composed of an eccentric shaft 1, an outer shell 2, a PDC drill 3, a cycloidal shaft 4, a needle tooth group 5, and a lower joint 6. Pintooth set 5 is made up of some pintooth pins 51 and pintooth sleeves 52 . in:

As shown in Figure 5, one end of the eccentric shaft 1 is provided with a connecting thread 11, and the middle part is provided with a positioning shoulder 13, and the center distance between the geometric center of the eccentric shaft section 12 and the geometric center of the eccentric shaft body is e.

As shown in FIG. 6 , connecting threads 22 and 23 are respectively provided at the upper and lower ends of the outer casing 2 . Gauge corrugations 21 are arranged on the outer cylindrical surface, and the gauge corrugations 21 can be in a straight structure or in a spiral structure, and the number of them is two or more. An axial shackle surface 25 is arranged on the upper end of the outer shell 2, and the shackle surfaces are arranged in pairs and symmetrically. On the inner cylindrical surface of the outer shell 2, there are at least two sets of gear seats 24 with different axial heights, which are matched with the pin gear pins 5. The axial height of each group of pin gear seats is the same, and Arrange evenly.

As shown in Figure 7, the lower end of the cycloidal shaft 4 is provided with a connecting thread 42, and its outer cylindrical surface is provided with a cycloidal tooth 41. It is a stepped channel structure.

As shown in Figure 8, one end of the lower joint 6 is provided with a connecting thread 61, and a shackle surface 62 is provided on the outer cylindrical surface. The shackle surfaces are arranged in pairs and symmetrically, and the inside is a straight hole or a stepped channel structure.

As shown in FIG. 9 , the PDC bit 3 is basically the same as the conventional PDC bit. It has a connecting thread 31 at one end, and a plurality of blades 32 are arranged on the cutting structure at the other end, and a plurality of PDC teeth 33 are fixed on the blade 32 .

The assembly relationship of the parts involved in this embodiment is: the connecting thread 14 on the eccentric shaft 1 and the output end 8 of the lower power drilling tool (such as screw drilling tool, turbo drilling tool, etc.) of the drill string system in oil drilling connected. The eccentric shaft segment 12 is inserted into the inner channel of the cycloid shaft and forms a rotating pair, and the outer cylindrical surface of the positioning shoulder 13 and the inner cylindrical surface of the outer shell 2 form a rotating pair and form a positioning relationship. The upper connecting thread 22 of the outer casing 2 is connected and fixed with the end 9 of the drill string system, and the lower connecting thread 23 is connected and fixed with the connecting thread 61 of the lower joint 6 . Pin gear pin 51 cooperates with pin gear sleeve 52 and pin gear pin 51 and pin gear seat 24 to form a pin wheel structure. The cycloidal tooth 41 on the cycloid shaft 4 cooperates with the above pin wheel structure and forms a meshing relationship. Wherein, the axial positioning of the needle tooth set 5 is realized by positioning the lower end surface 1 b of the shaft shoulder 13 and the upper end surface 6 a of the lower joint 6 . The PDC drill bit 3 is connected and fixed with the connecting thread 42 on the lower part of the cycloid shaft 4 through the connecting thread 31 thereon.

In this embodiment, if the PDC bit tool can work normally (continuously drill into rock breaking), three conditions must be met, one is to be able to continuously transmit drilling pressure to the PDC bit, the other is to continuously transmit torque to the PDC bit, and the third is A drilling fluid circulation path can be established. The WOB transmission method in this embodiment is that the WOB from the drill string system is transmitted to the eccentric shaft 1 through the connecting thread 14, and is transmitted to the 4a surface of the cycloidal shaft 4 through the 1b surface of the eccentric shaft, and then transmitted through the connecting thread 42 and its end surface. To the PDC drill bit 3; or through the 1d surface of the eccentric shaft to the 4c surface of the cycloidal shaft 4, and then to the PDC drill bit 3 through the connecting thread 42 and its end surface, so as to realize the WOB transmission of this embodiment. The torque transmission in this embodiment is produced by two kinds of transmission methods. One is that the rotational torque of the drill string system is directly transmitted to the outer casing 2 through the connecting thread 22, and then through the needle tooth group 5 and the cycloidal teeth on it. The gear pair of 41 is transmitted to the cycloidal shaft 4, and then transmitted to the PDC bit 3 through the connecting thread 42; the second is that the torque output by the downhole dynamic drilling tool (such as screw drilling tool, turbo drilling tool, etc.) is transmitted to the eccentric shaft through the connecting thread 14 1, and then transmitted to the cycloidal shaft 4 through the rotating pair formed by the 1c surface and the 4b surface and the gear pair of the pin tooth group 5 and the cycloidal tooth 41, and then transmitted to the PDC bit 3 through the connecting thread 42. The drilling fluid circulation in this embodiment is that the drilling fluid in the drill string system passes through the inner channel of the eccentric shaft 1 and the inner channel of the cycloidal shaft 4, and then enters the downhole annular space through the inner flow channel and nozzle of the PDC bit, and then establishes the drilling Liquid circulation system.

Further analysis will be made on the "alternating cutting track" characteristic of this embodiment below.

Figure 17 is a schematic diagram of the mechanism movement of the present embodiment, assuming that the transmission ratio between the eccentric shaft 1 and the cycloidal shaft 4 is i', and the eccentric distance of the eccentric shaft section is e. Take the geometric structure parameters of this embodiment respectively: when the number of teeth of the cycloid axis 1 is 7, the number of teeth of the needle tooth group 5 is 8, and the eccentricity e is 6, it is assumed that the speed of the downhole power drilling tool is 140 rpm, and the speed of the drill string system is 0 In rev/min, the single tooth 33 on the PDC bit 3 can realize the motion trajectory shown in Figure 18; assuming that the downhole power drilling tool rotating speed is 120 rev/min, when the drill string system rotating speed is 40 rev/min (transmission ratio i=3), the single tooth 33 on the PDC bit 3 can realize the motion trajectory shown in Figure 19; assuming that the downhole power drilling tool rotates at 120 rpm and the drill string system rotates at 60 rpm (transmission ratio i=2), the single tooth 33 on the PDC bit 3 can realize the motion trajectory shown in Figure 20; suppose the geometric parameter eccentricity e in this embodiment is changed to 12, and the kinematic parameter downhole motor speed is 120 rpm /min, when the rotation speed of the drill string system is 60 rpm (transmission ratio i=2), the single tooth 33 on the PDC bit 3 can realize the motion trajectory as shown in Figure 21. From the above analysis of the kinematic trajectory of this embodiment, it can be known that by reasonably matching the geometric parameters (number of cycloidal shaft teeth, number of pin teeth, eccentricity, etc.) ) can make the cutting teeth of the PDC bit obtain a more regular bottom-hole alternate cutting motion trajectory, and it is this characteristic that enables the PDC bit to obtain the beneficial effects mentioned in the "utility model content" of the utility model patent. Therefore, the alternating cutting trajectory movement realized by the utility model can significantly improve the ability of the PDC bit to penetrate into the formation, improve the rock-breaking efficiency, and is also beneficial to slow down the wear speed of the cutting teeth, especially in deep hard-drilled formations with high hardness and high abrasiveness. The formation has obvious technical advantages. Wherein, i is the transmission ratio of the downhole motor and the drill string system, and i' is the transmission ratio between the eccentric shaft 4 and the cycloid wheel 41.

Example 2:

As shown in Figure 10, this embodiment is basically the same as Embodiment 1, the difference being that passive wear-resistant teeth 211 or active cutting teeth 212 are fixed on the gage corrugated 21, or passive wear-resistant teeth 211 and Active cutting teeth 212 .

Under the ideal drilling conditions of the conventional PDC bit (the "ideal drilling condition" here refers to the working state in which the center of rotation of the bit coincides or nearly coincides with the center of the wellbore trajectory during the process of drilling and breaking the PDC bit), the cutting teeth rotate in one revolution cycle. The cutting amount and cutting load in the drill bit do not change much, so its mechanical stability is good (under ideal drilling conditions, the ratio of lateral unbalanced force to axial force of most PDC drill bits can be controlled within 5% level).

However, in this embodiment, the PDC bit performs alternating trajectory cutting motion, and the cutting amount and cutting load of the cutting teeth on it in one revolution cycle are always changing, so the overall mechanical stability of the PDC bit is greatly affected. Therefore, it is particularly important to strengthen the wear resistance and gauge ability of the gauge structure in this embodiment. In this case, the solution proposed in this embodiment can effectively reduce the negative impact on the overall drilling effect of the PDC bit caused by the cutting motion of the cutting teeth in alternating trajectories. On the one hand, the passive anti-friction teeth can effectively reduce the excessive wear on the gauge structure of the drill bit due to the high lateral unbalance of the drill bit, and play a role in protecting the structure of the drill bit body. At the same time, the drill bit gauge structure with high wear resistance can provide better righting and stability for the PDC bit, which is conducive to improving the drilling performance of the bit. On the other hand, the geometric outer diameter of the PDC bit in this embodiment is smaller than the size of the drilled hole. Under the condition of the bit doing the cutting motion of the alternating trajectory, it is often difficult to meet the requirement only by the gauge teeth or gauge teeth on the bit body. Requirements for regular borehole walls during drilling. Therefore, the introduction of active cutting teeth on the gage flute of the outer casing in this embodiment can effectively improve the gage ability of this embodiment, thereby improving the drilling quality and the drilling capability of the drill bit.

In this embodiment, the so-called "active cutting tooth" is defined as the fixing method of the cutting tooth on the gage block as "the angle between the normal line of the working surface of the cutting tooth and the radial line of the stabilizer at the point where the cutting tooth is located is relatively small." In general, the angle is not less than 60°. In this case, the cutting teeth can eat and scrape the well wall with a negative rake angle to achieve the effect of active diameter protection; the so-called "passive wear-resistant teeth" are defined as the cutting teeth in the The fixing method on the righting block is "the angle between the normal line of the cutter face and the radial line of the stabilizer at the position of the cutter is small", and the angle is generally less than 10°. In this case, the cutter can only Gauge by means of friction and extrusion is called passive gage.

Example 3:

As shown in FIG. 11 , this embodiment is basically the same as Embodiment 2, the difference being that three or more rows of needle holders 24 are vertically arranged on the inner cylindrical surface of the outer shell 2 .

In this embodiment, since the PDC bit is directly connected with the cycloid shaft, the loads it bears include axial pressure, torque, and bending moment, etc., especially in hard formations or heterogeneous formations, the instantaneous Shock loads are very high. Therefore, in this embodiment, the radial load fluctuation of the meshing force between the cycloidal shaft and the pin-tooth group is relatively large, and the distribution of the axial load is also very uneven. In order to improve the stability and reliability of the pin-tooth in meshing transmission, There are three or more rows of needle holders, which are used to support the needle pins and needle sleeves.

Example 4:

As shown in FIG. 12 , this embodiment is basically the same as Embodiment 3, the difference being that an eccentric bearing 7 is installed between the PDC bit 3 and the lower joint 6 . The eccentric bearing 7 can be a needle roller eccentric bearing, a sliding bearing, a cylindrical roller bearing, a double-row tapered roller bearing, or a self-aligning roller bearing.

Since in this embodiment, the PDC drill bit 3 is a cantilever structure in the state of track-changing eccentric rotary motion, its structural rigidity and mechanical stability are lower than those of conventional PDC drill bits. Introducing the eccentric bearing 7 in this embodiment can make the "eccentric wheel-PDC bit" mechanism into a double support structure, thereby improving the structural rigidity and mechanical stability of this embodiment, and achieving a better practical effect.

Example 5:

As shown in Figure 13, this embodiment is basically the same as Embodiment 4, the difference is that a thrust bearing set 10 is installed between the eccentric shaft section 12 of the eccentric shaft 2 and the inner surface 4b of the cycloid shaft 4; A radial bearing 15 is installed between the shoulder 13 of the eccentric shaft 1 and the inner surface of the outer casing 2 . In particular, the thrust bearing set 10 is a combination of not less than two TC type radial thrust bearings consisting of bearing inner rings, bearing outer rings and rolling elements; the radial bearings 15 are needle bearings or sliding bearings or rolling bearings Composite bearings.

In this embodiment, due to the eccentric rotation of the variable track of the PDC bit, the eccentric shaft and the cycloidal bearing are subjected to a large radial asymmetric force, and at the same time, the drilling pressure of the PDC bit needs to be transmitted from the eccentric shaft to the cycloidal shaft and then to the PDC bit. . Therefore, between the eccentric shaft and the outer shell, and between the eccentric shaft and the cycloid shaft, there will be a large contact friction force. In order to slow down the impact of this contact friction force on the friction and wear of the mechanical structure described in this embodiment, this embodiment is specially introduced. The thrust bearing set 10 and the radial bearing 15 are used to improve the working stability and prolong the service life of this embodiment.

Embodiment 6:

As shown in Fig. 14, Fig. 15 and Fig. 16, this embodiment is basically the same as Embodiment 5, the difference is that: the eccentric shaft segment 12 lower end face 1d of the eccentric shaft 1 and the end face 4c of the cycloid shaft 4 are provided A sealing ring 16 is provided; a floating sealing structure 17 is arranged between the lower joint 6 and the PDC bit 3 .

In this embodiment, a thrust bearing set 10, a radial bearing 15, and a cycloidal pin gear meshing mechanism are respectively provided, and these mechanisms or components have higher requirements on the working environment during work. On the one hand, it should have ideal lubrication conditions. On the other hand, it should try to avoid the hard particles in the external drilling fluid from entering the surface of the moving pair to cause abrasive wear. Therefore, in order to improve the practicability and reliability of this embodiment, it is very important to set the sealing mechanism. necessary.

In this embodiment, the floating sealing structure 17 is composed of a floating ring 17a, a sealing gland 17b, fastening bolts 17c, sealing rings 17d and spring washers 17e and the like. Sealing rings are arranged on the axial and radial planes of the floating ring 17a to realize the sealing between the PDC drill bit and the lower joint, and the floating ring can follow the trajectory of the PDC drill bit in the cavity between the lower joint and the sealing gland. With eccentric rotation, a "floating seal" can be achieved.

Embodiment 7:

As shown in Figures 22 and 23, this embodiment is the same as the above-mentioned embodiment, and the difference is that the pin wheel mechanism arranged on the inner wall of the housing is replaced by several gear teeth 20 of this embodiment, and the gear teeth 20 are set The inner wall of the housing can mesh with the cycloidal teeth 41 on the outer wall of the cycloidal shaft 4 for transmitting power torque. Of course, according to this example, it can be seen that the pin wheel structure can also adopt other ring gear structures and planetary gear mechanisms with similar functions, which can be used for matching and power transmission.

It can be seen from the above-mentioned embodiments that the PDC bit tool with alternating cutting tracks of the present invention combines a downhole transmission mechanism capable of producing eccentric swing rotation with the PDC bit, through the composite movement of the downhole transmission mechanism and the drill string system , can provide an alternate cutting motion trajectory for the PDC bit, one is to form a network cross cutting process on the bottom of the well, increase the ability of the cutting teeth of the drill bit to penetrate the rock, and improve the rock breaking efficiency; the other is to change the "cutting" Rock breaking is "alternate plowing" rock breaking, which can improve the self-sharpening and attacking ability of the drill bit, and is beneficial to slow down the wear speed of the cutting teeth; third, the alternating track cutting motion of the drill bit is "mandatory" and has high reliability . It has obvious technical advantages especially in deep hard-to-drill formations with high hardness and high abrasiveness. Specifically: first, the cutting motion of the alternating trajectory can effectively improve the rock-breaking drilling efficiency of the drill bit. The trajectory of the conventional fixed cutter PDC bit at the bottom of the well is circular, and each tooth performs scraping motion along its fixed rotation trajectory, whether it is the drilling and failure of the drill bit in the field, or the drillability experiment in the room. It can be reflected that the formation penetration ability of the PDC drill bit in this motion state affects the rock-breaking efficiency of the drill bit, especially in deep difficult-to-drill formations, and this impact is more serious. However, this patent can realize the cutting motion of the net-like alternating track at the bottom of the well, which is beneficial to the effective penetration of the rock by the cutting teeth and the crushing of the rock, thereby effectively improving the rock-breaking efficiency of the drill bit. Second, changing "cutting" rock breaking to "alternate plowing" rock breaking can improve the self-sharpening and attacking ability of the drill bit. When the conventional fixed-tooth PDC bit performs circular trajectory cutting motion at the bottom of the well, the cutting line speed direction and the normal direction of the working plane are fixed (relatively unchanged), that is, the working rake angle and edge inclination angle of the cutting teeth are fixed. . In general, the working rake angle of conventional drills is equivalent to the rake angle of the cutting structure (30°-10°), and the blade inclination angle is relatively small (generally within 5°). It is in the state of "negative rake angle bottom edge cutting". When the cutting teeth of the PDC bit perform alternating trajectory cutting motion, the blade inclination angle of the cutting teeth changes all the time during the movement (changes according to the law of sinusoidal curve). When the blade inclination angle is large to a certain extent, the contact motion state between the cutting teeth and the rock at the bottom of the well becomes "plowing" contact. This change in cutting state can effectively improve the aggressiveness of the drill bit, thereby improving the rock-breaking efficiency of the drill bit. At the same time, the change of the blade inclination angle is bidirectional, that is, changing the cutting of the bottom edge of the conventional cutting tooth to the left and right alternate double-edged cutting of the cutting tooth under the condition of alternating trajectory movement, the effect is to increase the wear resistance of the cutting tooth at the same time. The special self-sharpening ability of the cutting teeth improves the working performance of the drill bit. Third, the alternating track cutting motion of the drill bit is mandatory. Whether it is a cone-PDC composite drill bit or a wheel-type composite diamond drill bit, it is a combination of fixed tooth cutting structure and wheel body rotating cutting structure. The rotation of the wheel body is driven by the reaction force with the formation rock, which is passive. Rotational movement. There are many factors that affect the rotation of the wheel, such as the formation rock morphology and mechanical properties, the matching relationship between the cutting structure of the wheel and the fixed cutting structure, the drilling parameters and the friction between the wheel and the bearing or the journal, etc., so the rotation of the wheel There is uncertainty in the laws of motion. When under some special working conditions, the rotational comprehensive driving force direction of the wheel body may be perpendicular to the rotation linear velocity direction of the wheel body, that is, the dead point working condition, the wheel body will be "stuck" at this time. It is often observed in indoor experiments that the wheel body cannot rotate. In the structural scheme proposed by the utility model, the non-circular curve rotation motion power of the PDC bit comes from the inside of the tool, and the interaction force with the formation rock has little effect on its motion law, so it can ensure that the PDC bit realizes regular "interaction" Variable trajectory cutting motion", its work reliability is significantly improved.

The utility model is not limited to the aforementioned specific embodiments. The utility model extends to any new feature or any new combination disclosed in this specification, as well as the steps of any new method or process or any new combination disclosed.

Claims (11)

1. one kind has the PDC bit tool of alternation Cutting trajectory, it is characterized in that: it comprises eccentric shaft (1), shell body (2), PDC drill bit (3) and cycloid axle (4), described PDC drill bit (3) is fixedly connected on cycloid axle (4), described cycloid axle (4) is matched with in shell body (2) can become track eccentric rotary relatively, the upper eccentric shaft part (12) arranged of described eccentric shaft (1) is matched with in the inner chamber of cycloid axle (4) and forms revolute pair, the inner flow passage of described eccentric shaft (1), the inner flow passage of cycloid axle (4) is communicated with the inner flow passage of PDC drill bit (3).

2. there is the PDC bit tool of alternation Cutting trajectory as claimed in claim 1, it is characterized in that: the inwall of described shell body (2) is evenly equipped with some pin tooth groups (5) and forms pinwheel configuration, the outer wall of described cycloid axle (4) is provided with some cycloid tooths (41), and described cycloid tooth (41) is meshed with pinwheel configuration and forms engaged transmission relation;

Or the inwall of described shell body (2) is evenly equipped with some gear teeth (20), the outer wall of described cycloid axle (4) is provided with some cycloid tooths (41), described cycloid tooth (41) is meshed with the gear teeth (20) and forms engaged transmission relation.

3. there is the PDC bit tool of alternation Cutting trajectory as claimed in claim 2, it is characterized in that: described pinwheel configuration comprises the different pin toothholder (24) of the some axial heights be located on shell body (2) inwall, described pin toothholder (24) is combined with pin tooth group (5), make the axial height often organizing pin toothholder (24) identical, wherein said pin tooth group (5) comprises the gear pin (51) be matched with on pin toothholder (24), described gear pin (51) is arranged with pin gear sleeve (52).

4. the PDC bit tool with alternation Cutting trajectory as described in claim 1 or 2 or 3, it is characterized in that: described eccentric shaft (1) is threadedly connected on mud motor output (8), and described shell body (2) is threadedly connected on DRILL-STRING SYSTEM end (9).

5. there is the PDC bit tool of alternation Cutting trajectory as claimed in claim 4, it is characterized in that: in described engaged transmission relation, gearratio >=7:1 that described eccentric shaft (1) and cycloid axle (4) are formed, and the eccentric distance e≤6mm of the upper eccentric shaft part (12) of described eccentric shaft (1).

6. there is the PDC bit tool of alternation Cutting trajectory as claimed in claim 5, it is characterized in that: in described engaged transmission relation, the gearratio that described eccentric shaft (1) and cycloid axle (4) are formed is 7, and the eccentric distance e of the upper eccentric shaft part (12) of described eccentric shaft (1) is 6mm.

7. the PDC bit tool with alternation Cutting trajectory as described in claim 1 or 2 or 3, it is characterized in that: in described engaged transmission relation, gearratio >=7:1 that described eccentric shaft (1) and cycloid axle (4) are formed, and the eccentric distance e≤6mm of the upper eccentric shaft part (12) of described eccentric shaft (1).

8. the PDC bit tool with alternation Cutting trajectory as described in claim 1 or 2 or 3 or 5 or 6, it is characterized in that: cycloid axle (4) is limited in shell body (2) by the upper lower contact (6) connected of described shell body (2), be provided with capacity eccentric bearing (7) in described lower contact (6), described PDC drill bit (3) is through the capacity eccentric bearing (7) in lower contact (6) and be threadedly connected to the lower end of cycloid axle (4).

9. the PDC bit tool with alternation Cutting trajectory as described in claim 1 or 2 or 3 or 5 or 6, it is characterized in that: between described PDC drill bit (3) and lower contact (6), be provided with floating hermetically-sealed construction (17), described floating hermetically-sealed construction (17) comprises floating ring (17a), gland (17b) and sealing ring (17d), wherein on the axial plane and sagittal plane of floating ring (17a), be provided with sealing ring (17d), make to be formed between PDC drill bit (3) and lower contact (6) to seal, described gland (17b) is connected in lower contact (6), described floating ring (17a) is positioned between gland (17b) and lower contact (6), and track eccentric rotary can be become with in the cavity of PDC drill bit (3) between lower contact (6) and gland (17b).

10. the PDC bit tool with alternation Cutting trajectory as described in claim 1 or 2 or 3 or 5 or 6, it is characterized in that: described eccentric shaft (1) is provided with eccentric shaft part (12) and the location shaft shoulder (13), radial thrust bearing group (10) is provided with between the inner chamber of wherein eccentric shaft part (12) and cycloid axle (4), be provided with sealing ring (16) between the lower surface of described eccentric shaft and cycloid axle (4) to seal, between the described location shaft shoulder (13) and shell body (2), be provided with journal bearing (15).

11. PDC bit tools with alternation Cutting trajectory as described in claim 1 or 2 or 3 or 5 or 6, it is characterized in that: the outer wall of described shell body (2) is evenly equipped with some gauges stupefied (21), described gauge stupefied (21) is provided with some passive resistance to roll flutes (211) and/or active gage tooth (212); Described PDC drill bit (3) is provided with some wing structures, and described wing structure is furnished with some PDC teeth.