WO2013170788A1

WO2013170788A1 - Combination scraping and impacting drill bit

Info

Publication number: WO2013170788A1
Application number: PCT/CN2013/075839
Authority: WO
Inventors: 杨迎新; 陈炼; 林敏�; 包泽军; 陈世彬; 石擎天
Original assignee: 西南石油大学
Priority date: 2012-05-18
Filing date: 2013-05-17
Publication date: 2013-11-21
Also published as: CN102678055B; CN102678055A

Abstract

Disclosed is a combination scraping and impacting drill bit, belonging to the field of rock-breaking tools for drilling equipment for petroleum and natural gas, mine engineering, fundamental architectural engineering construction, geology, hydrology, etc. The drill bit comprises a drill bit body (1) and a fixed cutting structure (2) consolidated onto the drill bit body (1); further the drill bit body (1) is provided with an impact cutting structure (3); the impact cutting structure (3) comprises a transmission mechanism (32) for transmitting the impact force, and impact cutting teeth (31); the impact cutting tooth (31) is consolidated onto a punch (321) at the end of the transmission mechanism (32); and the punch (321) can slide or slidingly impact relative to the drill bit body (1) in the direction of impact force transmission. By comparison with a traditional PDC drill bit, the present drill bit is not only favourable for the cutting tooth of the drill bit entering into earth strata such that the rock-breaking efficiency is improved, but also favourable for the wear rate of the cutting tooth to be reduced, and particularly the present drill bit has an obvious technical advantage in the conditions of hard earth strata with relatively high strength and comparatively strong grindability.

Description

Scratch-impact composite drill bit

Technical field

The invention belongs to the field of rock breaking tools for drilling equipment for oil and gas, mining engineering, building foundation engineering construction, geology and hydrology.

Background technique

A drill bit is a rock breaking tool used in drilling engineering to break rock and form a wellbore. The conventional drill bits used in today's drilling projects mainly include three-cone drill bits, polycrystalline diamond composite drill bits (ie PDC drill bits) and rotary drill bits (also called rotary drill bits or drill bits).

The tri-cone bit is mainly broken in the form of crushing (the tooth is crushed into the rock to cause rock breakage). The applicable stratum is wide, but the energy utilization rate is not high and the rock-breaking efficiency is relatively low. Especially in the deep stratum drilling, under the action of high-density drilling fluid, the chip holding effect of the bottom hole is very obvious. It is difficult for the teeth to be pressed into the formation and form effective crushing. The drilling speed of the drill bit is greatly limited. Low bearing life is one of the main factors that limit the service life of the tri-cone bit. The tri-cone bit needs a large drilling pressure to ensure high rock breaking efficiency, so the bearing load amplitude is high, and the working principle of alternately breaking the rock on the cone will inevitably lead to the axial or longitudinal vibration of the bit, and a large extent. Bearing load fluctuations. In addition, the working condition of the roller cone bit bearing in the downhole is bad, and the life of the bearing seal is difficult to guarantee, so the bearing life of the tri-cone bit is relatively short.

The PDC drill bit is a drill bit that uses a polycrystalline diamond compact (ie, a PDC tooth, also referred to as a tooth) to fracture the rock by shearing or shearing. Due to the outstanding advantages in cutting element performance and rock breaking method, the rock breaking efficiency of PDC bit in soft to medium hard formation is significantly higher than that of tri-cone bit. Today, PDC drill bits are used more and more in drilling engineering, and the proportion is getting larger and larger, but for hard, highly abrasive formations and severely heterogeneous formations, PDC drill bits are still difficult to adapt. The existing PDC drill bits are fixed cutting tooth drills (no moving parts on the drill bit), and the polycrystalline diamond composite sheets as cutting elements are arranged according to a certain regularity and are fixed on the bit body to constitute a cutting structure of the PDC bit crushing rock. In order to carry the cuttings broken down by the drill bit to the ground in time, and also to clean the drill bit and cool the cutting teeth, the PDC bit needs to have a hydraulic structure. The hydraulic structure usually consists of a flow path inside the drill bit, an outer flow path, and an injection hole. The injection hole, also called a nozzle, may be a fixed nozzle directly disposed on the bit body, or may be a replaceable nozzle mounted on the drill bit. In order to achieve better working results of the cutting structure and hydraulic structure of the drill bit, when designing and manufacturing the drill bit, the PDC teeth are usually divided into several groups according to a certain rule, and the PDC teeth of the same group are fixed on the same tooth holder, and each The tooth holders and the PDC teeth distributed thereon form a cutting structure unit called a blade wing (the tooth holder is a blade body). The grooves between the blades form the outer flow path of the drill bit. This type of drill is a blade-type PDC bit. Knife-wing PDC bits are the main structural type of PDC bits. For PDC bits, the rock breaking efficiency of the drill bit depends mainly on the ability of the PDC tooth to eat into the rock under the same conditions of the bit rotation speed and the bit pressure. The greater the depth of the PDC tooth into the rock, the higher the bit rock breaking efficiency. . Generally, when drilling in soft formations, PDC bit cutting teeth have a deeper depth of ingestion, and the bit breaking efficiency of the bit is higher. When the hard formation is drilled, the cutting tooth has a weaker eating ability and the eating depth becomes smaller. The drilling efficiency of the drill bit is significantly reduced. The main disadvantages of PDC drills are: First, when the strength or hardness of the rock is high, the PDC teeth are difficult to eat into the rock to form an effective scraping, especially when the PDC teeth are worn, the teeth are more difficult to eat into the formation. The ROP of the drill bit will drop dramatically. Second, the PDC teeth continuously cut the rock, and the heat generated by the intense friction causes the teeth to reach a relatively high temperature, when the temperature exceeds one. When the limit is set, the wear speed of the PDC tooth rises remarkably, which leads to the occurrence of thermal wear (the phenomenon that the wear resistance of the PDC tooth is significantly lower than the specific temperature of the PDC tooth is called the thermal wear phenomenon of the PDC tooth). . Third, the wear speed of the PDC teeth on different radial areas of the PDC bit is significantly different. Generally, the outer teeth of the drill bit (especially the outer 1/3 of the drill radius) wear faster than the teeth in the core region. The tooth wear balance is poor, which reduces the overall performance of the drill bit.

The rotary drill bit is a fixed-tooth rock breaking tool used in a drilling well with a down-the-hole impactor (ie, a down-the-hole hammer). The structure of the rotary drill bit is similar to that of the PDC drill bit. There are no moving parts on the drill bit, and the bit body is fixed with a certain number of cutting teeth that can cover the area to be broken in the bottom of the well. The main difference is that the cutting elements of the PDC drill bit are mainly PDC teeth, while the cutting elements of the rotary drill bit are mainly cemented carbide or diamond composite teeth with the shape of the teeth of the roller cone bit. The rock breaking mechanism of the rotary drill bit is significantly different from the crushing mechanism of the roller cone bit and the cutting mechanism of the PDC bit. The rotary drill bit relies on the instantaneous impact of its teeth to break the rock at the bottom of the well. The upper end of the rotary drill bit is connected with a down-the-hole impactor. When the down-the-hole impactor is in operation, its hammer reciprocates under the action of circulating fluid (drilling fluid or circulating gas), repeatedly hitting the drill bit or the bit, thereby The drill bit teeth in contact with the bottom rock provide a pulsating shock load, and the rock breaks under the instantaneous impact of the teeth. Since the impact load of the drill bit depends on the down-hole impactor, it is not necessary to apply a large weight-on-bit during the operation of the rotary drill bit. This feature is significantly different from the roller bit bit. The roller bit must be under the large drill pressure. To achieve higher rock breaking efficiency), it is only necessary to press the drill bit to the bottom of the well with a small drilling pressure. Typically, a rotary drill bit achieves higher rock breaking efficiency when drilling in a brittle formation, especially a harder brittle formation. In addition, in the easy-sloping stratum with large dip angles, drilling with a rotary drill bit is beneficial to reduce the tendency of the well.

Baker Hughes of the United States has proposed a roller-PDC hybrid drill bit (patent application in the United States and other countries, such as PTC W02010/132232, etc.), which adds a cone to the traditional PDC cutting structure. The cutting structure (or the cone member) can be said to be a combination of a fixed cutting structure and a cone cutting structure. The fixed cutting structure of the hybrid drill bit consists of a number of PDC fixed blades with fixed cutting teeth (PDC teeth) arranged on the blade. When the drill bit is drilled, the PDC teeth on the fixed blade are broken by way of scraping; The toothed wheel cutting structure is similar to that in the roller bit bit. The toothed wheel is mounted on the journal of the tooth, and the tooth palm forms a fixed whole with the bit body. The cone rotates around the journal while rotating with the bit body. The teeth on the cone are mainly broken by crushing. This hybrid bit combines the features and benefits of a PDC bit and a roller bit. When drilling under certain conditions, the bit performance is superior to PDC and roller bits. However, the drill bit also has the following disadvantages: First, the axial direction of the cone cutting structure and the fixed cutting structure (the axial direction of the drill bit) or the longitudinal overall movement are uniform. Therefore, the up and down vibration inevitably generated during the working process of the cone cutting structure will directly affect the working stability of the PDC fixed cutting structure, which leads to two adverse consequences: First, the impact load caused by the longitudinal vibration easily causes the PDC teeth. Damage, reduce the service life of the drill bit; Secondly, the longitudinal vibration will cause frequent changes in the depth of PDC teeth in the fixed cutting structure. In severe cases, the PDC teeth may be frequently removed from the bottom of the well, thus reducing the drill bit to a certain extent. Rock breaking efficiency. Secondly, the cone is connected to the shank of the tooth through the bearing system. Due to the strength requirement, the geometry of the cone cutting structure is relatively large, occupying a valuable and limited space on the drill bit, which is not conducive to the fixed cutting structure on the bit body. And the layout of the hydraulic structure. The large size requirements of the cone cutting structure also limit the application of the drill bit in deep well drilling. Third, the bearing working life of the cone cutting structure has obvious constraints on the overall life of the drill bit.

Summary of the invention The object of the present invention is to provide a scraping-impact composite drill bit, which increases the impact cutting structure on the basis of the fixed cutter bit, fully utilizes the advantages of the impact rock breaking mode, improves the bite of the cutting teeth on the rock, and improves the breakage. Rock efficiency, slowing the wear speed of the cutting teeth, increasing the service life of the drill bit, and improving the working performance of the drill bit in difficult to drill formations with high strength, strong abrasiveness or strong heterogeneity.

The object of the present invention is achieved by the following technical solutions:

A scraping-impact composite drill bit (referred to as a composite drill bit), comprising a bit body and a fixed cutting structure fixed on the bit body, the compound drill bit is provided with an impact cutting structure, and the impact cutting structure includes a force transmitting mechanism for transmitting the impact force And the impact cutting teeth are fixed on the punch at the end of the force transmitting mechanism, and the punch can slide or slide against the bit body in the direction of the impact force transmission.

Specifically, the scraping-impact composite drill includes a bit body, a fixed cutting structure, an impact cutting structure, and a hydraulic structure, and may also include an impact mechanism that generates an impact force, and the impact cutting structure includes a force transmitting mechanism that transmits the impact force and the impact cutting tooth. The force transmitting mechanism includes an anvil body, a force transmission rod and a punch which are sequentially connected, a relative sliding between the anvil body and the bit body, a relative sliding between the force transmitting rod and the bit body, or formation by the swinging slider to allow relative The sliding, which allows a relatively rotating connection, is connected to the end of the force-transmitting rod, and the impact cutting teeth are fixed on the punch, and the punch can slide or slide against the bit body in the direction of the impact force transmission. The bit body is not only a base for attaching, supporting or accommodating the drill fixed cutting structure, the impact cutting structure and the impact mechanism, but also a base body for mounting the nozzle and forming the drill flow path. The upper end of the bit body (i.e., the circulating fluid inlet end, referred to as the inlet end) is provided with threads for connecting the drill string. The upper part of the bit body is a tubular structure, and the pipe wall has the function of transmitting the weight of the drill pipe, and also functions to isolate the space inside and outside the pipe, and the inner hole space is used for setting the components such as the anvil in the force transmission mechanism. An impact mechanism can also be provided therein. The lower part of the bit body is mainly a base body for fixing the cutting structure, and a hole or a groove for accommodating the force transmission rod is opened thereon, and a circulating fluid injection hole is also provided. Except for the punch, the impact cutting teeth and the exposed portion of the force-transmitting rod, the other parts of the impact-cutting structure are located in the inner space of the bit body and are mounted from top to bottom in the order of the anvil-transmitting rod-punch. When the composite drill bit comprises an impact mechanism, the top-down installation sequence is: an impact mechanism, an anvil body, a force-transmitting rod, a punch, an impact force generated by the impact mechanism acts on the anvil, and then transmitted from the anvil to the force transmission. Rod, punch. The upper end surface of the anvil is a working surface subjected to an impact load, and the lower end is connected to the force-transmitting rod, and may be a sliding connection, an articulation (ie, a hinge connection), or a direct connection. When the sliding connection is adopted, the anvil and the force-transmitting rod can slide relative to each other along the contact surface; when the joint is connected by an articulation, the anvil and the force-transmitting rod can be relatively rotated about the hinge center. The punch is connected to the other end of the force-transmitting rod by means of a thread, an interference fit, a pin, a welding, or the like, or forms an integral element with the force-transmitting rod. A punch, the impact cutting teeth fixed on it and the matching force-transmitting rod constitute an impact cutting unit, and the number of impact cutting units may be one or several. In the same impact cutting unit, the number of the force transmission rods is one or more than one. When the number of the force transmission rods is more than one, the force transmission rods are serially connected to each other, and the adjacent force transmissions having relative motions with each other The rods are connected by a hinge. The connection or installation between the force transmitting mechanism and the bit body and the components of the force transmitting mechanism enables the punch to slide relative to the bit body in the direction of impact load transmission. The fixed cutting structure is disposed at the outer end of the lower part of the bit body, and includes a cutting tooth base (when the fixed cutting structure adopts a blade type structure, the cutting tooth base is a fixed blade) and a fixed cutting tooth, and the cutting tooth base is consolidated. On the bit body, a fixed connection is formed with the bit body, or combined with the bit body to form an integral structure, and the fixed cutting teeth are fixed on the cutting tooth base. The hydraulic structure mainly includes internal and external flow passages of the drilling circulating fluid, and nozzles installed at the outlet of the internal flow passage. There are also some auxiliary components on the drill bit, including to ensure that the anvil works correctly. A righting sleeve provided at a position, a slider, a pin, and the like provided to realize a connection between the anvil and the force receiving rod, and a sealing member.

One of the key points of the present invention is that the fixed cutting structure and the impact cutting structure are combined to form a composite cutting structure, and the impact cutting teeth on the punch continuously impact the bottom of the well at a certain frequency under the impact force, and cooperate with the fixed cutting structure on the drill bit. Complete the fracture of the bottom rock. In particular, when the impact cutting teeth on the punch are distributed in the outer region of the radial direction of the drill bit (especially in the outer 1/3 region of the drill radius), the rock breaking action of the impact cutting teeth causes the fixed cutting teeth in the region to eat and cut the rock. The required force is significantly reduced, and the wear rate is significantly reduced, so that the balance of the wear of the cutting teeth on the fixed cutting structure can be remarkably improved, and the wear speed of the fixed cutting teeth in the core region and the outer region of the drill bit is close to the synchronization. Regarding the arrangement and number of the fixed cutting structure and the impact cutting structure on the bit body, those skilled in the art can have numerous options in combination with the prior art under the teachings of the present specification, and these technical solutions are all within the scope of the present invention.

The second key to the invention is that the punch can make a sliding or sliding impact relative to the bit body in the direction of impact force transmission. The resulting effect is: First, the weight of the drill bit transmitted from the drill string to the bit body is not applied to the impact cutting teeth, thereby avoiding the rapid wear that the impact cutting teeth may undergo under continuous large drilling pressure; Second, the pulsating impact load of the impact cutting structure is not transmitted to the bit body or even the drill string, which avoids the adverse effects that the pulsating impact load may have on the safety of the bit body and the drill string. Third, it helps the impact mechanism to be air defense. The implementation of the function. Regarding the structure of the impact cutting structure for realizing the sliding of the punch relative to the bit body in the impact direction, those skilled in the art can have many options in combination with the prior art under the teaching of the present specification, and these technical solutions are all within the scope of the present invention. within.

The fixed cutting teeth on the fixed cutting structure are polycrystalline diamond composite sheets, or may be thermally stable polycrystalline diamond, natural diamond and impregnated diamond cutting teeth, and the impact cutting teeth on the impact cutting structure are cemented carbide teeth, or Surface-reinforced carbide teeth with diamond. The shape of the carbide tooth used as the impact cutting tooth may be a spherical tooth, a cone tooth, a wedge tooth, a side wedge tooth, and a scoop tooth, or may be a tooth of other shapes having a good impact rock breaking effect.

A sealing device is arranged on the sliding surface of the force transmitting mechanism (mainly the force transmission rod) matched with the bit body to avoid leakage of the circulating fluid and erosion of the force transmitting rod and the bit body during the leakage process, and at the same time, due to the circulation The pressure of the fluid in the inner cavity of the bit is higher than the outside of the bit body, and the pressure difference between the inner and outer acts on the force transmitting mechanism, generating a thrust pushing the punch outward, which can make the cutting teeth on the punch press against the rock surface, which is beneficial to improve cutting. The impact of the teeth on rock breaking efficiency.

The impact cutting teeth of the impact cutting structure may be disposed within a radial coverage of the fixed cutting teeth of the fixed cutting structure, or may be independently arranged (not overlapping with the radial coverage of the fixed cutting structure fixed cutting teeth), Or partially arranged independently.

Preferably, the impact cutting teeth of the impact cutting structure and the fixed cutting structure fixed cutting teeth are arranged in a radial overlapping manner, and the impact cutting teeth of the impact cutting structure are arranged in a radial region other than one third of the radius of the drill bit. Inside.

Preferably, the impact cutting teeth of the impact cutting structure and the fixed cutting structure fixed cutting teeth are arranged in a radial overlapping manner, and the impact cutting teeth of the impact cutting structure are arranged in a radial region other than one-half of the radius of the drill bit. Inside.

Preferably, the impact cutting teeth of the impact cutting structure and the fixed cutting structure fixed cutting teeth are arranged in a radial overlapping manner, and the impact cutting teeth of the impact cutting structure are arranged in a radial direction other than two-thirds of the radius of the drill bit. Within the area. Preferably, the impact cutting teeth of the impact cutting structure are disposed within a radial extent within one third of the radius of the drill bit.

The force transmission mechanism is provided with an anti-drop structure to prevent the punch and the force transmission rod from falling off the drill bit under the pulling force. The force transmission mechanism may also be provided with an anti-rotation structure to prevent the punch from rotating around the force transmission shaft during the working process. Preferably, the cutting teeth of the fixed cutting structure are polycrystalline diamond compact sheets (PDC teeth), and the cutting teeth of the impact cutting structure are made of cemented carbide teeth or cemented carbide teeth reinforced with a superhard material such as diamond.

Preferably, the cutting teeth of the fixed cutting structure adopt a circular polycrystalline diamond composite sheet, and the cutting teeth of the impact cutting structure adopt a cone-shaped or wedge-shaped cemented carbide tooth or a diamond composite cemented carbide tooth.

Preferably, when the scraping-impact composite drill bit comprises an impact mechanism, the bit body adopts a split structure, and the impact mechanism and the corresponding bit body portion thereof are separated from the composite drill bit to form a single body. component. At this time, the bit body is connected by the impactor body provided with the impact mechanism and the cutting structure body provided with the fixed cutting structure and the impact cutting structure, and the impact mechanism is installed in the hollow part of the impactor body, and the impactor body is used for accommodating and installing. Impact mechanism. At this point, the composite drill bit is divided into two functionally and manufacturingly independent sections, namely the upper impactor and the lower rock breaking tool. The function of the impactor is to provide pulsating impact. The function of the rock breaking tool is to transmit the impact force and perform direct crushing of the rock together with the fixed cutting structure. The use of a split structure is more conducive to the manufacture and use of composite drill bits. The impactor components and rock breaking tool components can be manufactured separately and assembled before being used in the well.

For a scraping-impact composite drill including an impact mechanism, the working process is:

A scraping-impact composite drill bit is attached to the extreme end of the drill string. After entering the well, the drill bit gradually approaches and reaches the bottom of the well. The circulating fluid drive device is activated (when the circulating fluid is drilling fluid, the driving device is a drilling pump; when the circulating fluid is gas or mainly gas, the driving device is a gas compressor), and the circulating fluid is circulated inside and outside the drill string. The drilling pressure is applied to the drill bit and the rotary drilling is started. The cutting teeth on the drill fixed cutting structure start to break the bottom rock. At the same time, since the circulating fluid has started to circulate, the impact mechanism starts to work under the driving of the circulating fluid inside the drill string, and a pulsating impact load of a certain frequency range is continuously applied to the anvil, and the impact load is transmitted to the force transmission rod through the anvil. , then transferred to the punch, and finally applied to the impact cutting teeth, so as to achieve the impact of the cutting structure on the bottom of the rock. After the circulating fluid flows through the impact mechanism, it flows out from the drill bit or the nozzle through the internal flow passage, and completes the functions of cooling the cutting teeth, cleaning the drill bit, cleaning the bottom of the well, and carrying the cuttings. Although the rock breaking work of the fixed cutting structure and the impact cutting structure is carried out separately, the rock breaking mechanism is also different, but beneficial interactions occur between them. The compound drill bit usually has a fixed cutting structure as the main cutting structure, and the impact cutting structure is an auxiliary cutting structure. The cutting teeth in the fixed cutting structure are usually PDC teeth (or PDC teeth), so the fixed cutting structure on the composite drill bit is equivalent to a common fixed cutting tooth PDC bit. The key to the rock breaking efficiency lies in the PDC teeth. The effect of eating on the bottom of the rock. To increase the depth of penetration of PDC teeth, it is usually only possible to increase the weight of the drill, and the increase in the weight of the drill is limited, and increasing the weight of the drill will increase the wear of the PDC teeth and reduce the working life of the drill. The technical solution of the present invention can effectively utilize the characteristics and advantages of the impact rock breaking mode by introducing the impact cutting structure on the fixed cutting bit, and significantly improve the rock breaking efficiency and the working life of the cutting tooth of the fixed cutting structure. The impact cutting structure relies on the pulsating impact load of the impact cutting teeth on a certain frequency of the rock to break the rock, so the requirement for the working drilling pressure is very low, and the impact effect of the cutting teeth on the bottom rock is formed in the corresponding area of the bottom of the well. Pit or press into the pit, the production of these crushing pits or press-in pits directly promotes the intrusion of the PDC teeth in the corresponding area of the fixed cutting structure to the bottom rock, and at the same time reduces the workload of these PDC teeth. In other words, when the cutting teeth of the fixed cutting structure have many crushing pits When drilling on the uneven bottom of the well, the drilling speed is significantly higher than the drilling speed on the smooth bottom, and the wear speed of the cutting teeth is significantly lower than the wear speed when drilling on the smooth bottom. .

In the impact cutting structure of the composite drill bit, the components (including the anvil, the force rod, the punch and the cutting teeth, etc.) that are subjected to the pulsating impact load in the impact cutting structure can slide relative to the bit body in the direction of the impact load transmission or Sliding impact. Thus, during the normal drilling of the drill bit, the impact cutting structure does not withstand the drilling pressure from the drill string and the bit body, and the fixed cutting structure does not withstand the pulsating impact load of the impact cutting structure. This feature not only avoids the damage or adverse effects of the pulsating impact load on the cutting teeth of the fixed cutting structure, the bit body or even the upper drill string, but also avoids the rapid wear of the impact cutting teeth due to continuous large drilling pressure. In addition, this feature provides the necessary conditions for the anti-aircraft function of the composite drill bit. During the operation of the drill bit, due to gravity and the pressure difference between the internal and external pressure of the circulating fluid, the anvil, the force transmission rod, the punch and the impact cutting teeth in the impact cutting structure will slide down together for a distance, so that the impact cutting teeth protrude. In addition to the fixed cutting structure cutting the enveloping contour surface, the position at which the impact cutting structure is located at this time is the anti-emptive position, in which the anti-air strike design of the impact mechanism enables the impact hammer in the impact mechanism to stop against the anvil Hammering to achieve no-load protection of the impact cutting structure. As the drill bit approaches and reaches the bottom of the well, the protruding impact cutting teeth first contact the bottom of the well, and as the drill bit is further seated, the aforementioned components in the impact cutting structure are gradually retracted to the normal operating position. When the drill bit is fully seated at the bottom of the well, the drill bit begins to spin, and the impact cutting structure and the fixed cutting structure begin normal rock breaking work. When it is necessary to lift the drill bit (such as drilling or continuation of the drill string), as the drill bit position gradually rises, contrary to the drill down process, the fixed cutting structure on the drill bit first leaves the bottom of the well, and the impact cutting teeth remain with the well. The bottom rock contacts, and at the same time, the aforementioned other related components in the impact cutting structure slide down relative to the bit body until reaching the runaway position, after which the impact cutting teeth are no longer subjected to the impact load, and then off the bottom of the well, as the other parts of the drill bit rise.

For a scraped-impact composite drill that does not include an impact mechanism, the process of generating a pulsating shock load is no longer completed by the composite drill but by the impactor. In addition, the rest of the work process is the same as that of the scraping-impact composite drill bit that includes the impact mechanism. A scraping-impact composite drill that does not include an impact mechanism is not a fully functional drill and must be installed in conjunction with the corresponding impactor before it can be used. The composite drill bit at this point is actually the rock breaking tool component of the split scraping-impact composite drill bit. In the specific use, the matched impactor should be connected with the composite drill bit (the impactor is connected to the upper end of the composite drill bit), and then the combined impactor and composite drill bit are connected at the end of the drill string. After the installation is completed, it can be used down the well.

The beneficial effects of the invention:

(1) When the composite drill bit is drilled in the bottom of the well, in the bottom hole area where the fixed cutting teeth and the impact cutting teeth overlap, the crushing pit or the crushing pit is formed on the bottom surface of the well due to the continuous impact of the impact cutting teeth on the rock. , making the bottom of the well become uneven. The cutting force of the PDC tooth when cutting on the rugged rock surface (ie, the pressing force perpendicular to the rock surface) under the same cutting depth (infeed depth) or the cutting volume (the volume of the rock being crushed by the cutting), the main cutting The force (cutting force in the direction of cutting speed) and the cutting process are significantly lower than the cutting process under the condition that the rock surface is relatively flat (no crushing pit). The difficulty of cutting the teeth into the rock is significantly reduced, and the energy consumption of rock breaking is also significantly reduced. Therefore, compared to conventional PDC drills, composite drills achieve higher rock breaking efficiencies when drilling in formations where the cutting teeth are difficult to eat (higher hardness formations).

(2) As mentioned above, under the same cutting depth or cutting volume, the frictional power consumption of PDC teeth when cutting on uneven rock surface is significantly lower than that of rock surface with relatively flat surface (no fracture pit). Due to The amount of heat generated by rubbing is also significantly reduced. On the other hand, when cutting on uneven rock surface, the contact area and contact state between the cutting teeth and the rock change frequently, and the cooling effect of the cutting teeth can be improved. Therefore, compared with the conventional PDC drill bit, the composite drill fixed cutting structure has lower wear speed of the cutting teeth and is less prone to thermal wear, which can achieve higher working life, and thus is difficult to adapt to high abrasiveness and high in conventional PDC drill bits. Composite drills can achieve better drilling results when used in hard-to-drill formations such as hardness and high heterogeneity.

(3) When the overlapping area of the fixed bit and the impact cutting tooth of the composite bit is the radially outer area of the bit (such as the outer two-third area of the bit radius, the outer half area, or the outer one-third area) When the outer teeth of the fixed fixed-tooth bit (especially the outer 1/3 of the bit radius) wear faster than the teeth in the core region, the rock breaking action of the impact cutting teeth enables the cutting of the region. The wear rate of the teeth is significantly reduced, so the balance of the wear of the cutting teeth on the fixed cutting structure can be significantly improved, that is, the wear speed of the fixed cutting teeth in the core region and the outer region of the drill bit is close to synchronization. For composite drills with a fixed cutting structure (especially a cutting structure consisting mainly of PDC teeth) as the main cutting structure, this effect of improving the wear balance of the fixed cutting teeth is particularly important for improving the overall performance of the drill bit.

(4) In the brittle-strength stratum, impact rock breaking can achieve better rock breaking effect. Although the teeth on the cone in the cone-PDC hybrid drill bit also exert a certain degree of dynamic load on the rock during the crushing of the rock, the time at which the composite drill bit impacts the cutting tooth per impact on the bottom of the well (contact time) is higher than that of the tooth. The wheel teeth are much shorter, the impact effect is more obvious, and the higher impact frequency can be achieved. Therefore, when drilling in a brittle formation, the composite drill bit is not only superior to the conventional PDC bit, but also can be mixed with the cone-PDC. The bit has a better rock breaking effect.

(5) The impact cutting structure in the composite drill bit and the cone in the cone-PDC hybrid drill bit belong to the moving cutting structure, but the force transmitting mechanism in the composite drill bit can slide relative to the bit body in the direction of the impact load transmission. The beneficial effects are as follows: First, the drilling pressure transmitted from the drill string to the bit body is not applied to the impact cutting teeth, thereby avoiding the rapid wear of the impact cutting teeth under continuous large pressure holding; Second, the pulsating impact load of the impact cutting structure will not be transmitted to the bit body or even the drill string, so that the up and down vibration of the moving cutting structure (cone) existing in the cone-PDC hybrid bit may be fixed to the cutting tooth, the bit body and even The drill string causes damage and reduces the rock breaking efficiency of the fixed cutting structure (PDC tooth), which is better solved in the composite drill bit. Third, it contributes to the realization of the anti-airback function of the impact mechanism.

(6) The center of the fixed cutter bit usually has an inner cone area, and the composite drill bit can be provided with an impact cutting structure in this area (for example, the impact cutting teeth of the impact cutting structure are arranged in a radial area within one third of the radius of the drill bit) Inside), the raised conical bottom is more likely to undergo volumetric crushing under the impact force of the impact cutting teeth, and the rock breaking speed at the center of the bottom hole is significantly accelerated, thereby promoting the rock breaking efficiency.

(7) For a composite drill bit with a fixed cutting structure capable of covering all (or nearly all) radial areas of the bottom of the well, the fixed cutting structure can still operate independently when the impact mechanism or the impact cutting structure fails or is inefficient due to various reasons. This feature of the composite drill bit is superior to conventional rotary drill bits.

(8) Compared with the cone-PDC hybrid drill bit, the space occupied by the punch in the tooth area of the drill bit is relatively small, which is beneficial to the structural design of the drill bit, especially to facilitate the use of more space in the design to increase the fixed cutting. Tooth, to improve the working life of the fixed cutting structure of the drill bit.

DRAWINGS

Figure 1 is a schematic view of the structure of the present invention, the composite drill bit does not include an impact mechanism, has three fixed blades, and three sets of impact The cutting unit, the fixed blade and the punch are arranged between each other, and the joint portion adopts an external thread structure. In the figure: 1, bit body, 2, fixed cutting structure, 21, fixed cutting teeth, 22, fixed blade, 3, impact cutting structure, 31, impact cutting teeth, 321, punch, 41, flow channel, 42, nozzle.

Figure 2 is a view (i.e., top view) of the composite drill bit of Figure 1 as seen from the end of the cutting structure toward the joint end.

Fig. 3 is a cross-sectional view showing the impact cutting structure partially cut away from the composite drill shown in Fig. 1. In the picture: 32, force transmission mechanism, 322, dowel bar, 323, anvil, 325, sealing ring.

Figure 4 is an exploded perspective view of the composite drill bit of Figure 1 (to illustrate the mounting relationship, the bit body 1 is laterally split from the middle).

Figure 5 is a schematic view of the structure of the present invention (a schematic cross-sectional view of the impact cutting structure formed after partial cutting), the composite drill bit does not include an impact mechanism, and there are two force-transmitting rods in the impact cutting unit, one of which is a force-transmitting rod and a punch Fixed connection (or integral structure), another force-transmitting rod is connected with the anvil through a hinge (forming a rotating pair), and two force-transmitting rods are also connected by a hinge (forming a rotating pair); An anvil centering sleeve is arranged between the bit bodies. The joint is made of an internal thread. In the figure: 324, righting sleeve, 326, hinge pin, 327, connecting screw, 3221, force bar (1), 3222, force bar (2).

Fig. 6 is a schematic diagram of the principle of correcting and positioning the anvil body (ie, the transverse section of Figure 5 at the position of the righting sleeve 324). Fig. 7 is a schematic view showing the principle of the righting and positioning of the anvil without the righting sleeve (the anvil 323 is in contact with the inner hole wall of the bit body 1, forming a clearance fit to realize the righting and positioning of the anvil).

Figure 8 is a top plan view of the present invention having two fixed blades, two sets of impact cutting units, and a fixed blade and a punch disposed therebetween.

Figure 9 is a schematic view of the structure of the present invention. The composite drill has three fixed blades and two sets of impact cutting units.

Figure 10 is a diagram showing the radial coverage of the composite drill bit when the impact cutting teeth are placed outside the radius of the drill bit. Figure 11 is a diagram showing the radial coverage of the composite drill bit when the impact cutting teeth are placed outside the radius of the drill bit. Figure 12 is a diagram showing the radial coverage of the composite drill bit when the impact cutting teeth are placed in an area other than two-thirds of the radius of the drill bit. Figure 13 is a diagram showing the radial coverage of the composite drill bit when the impact cutting teeth are placed within one third of the radius of the drill bit. Figure 14 is a perspective view of the radial face of the composite drill bit when the impact cutting teeth are arranged over the entire radial extent except for the small portion of the center of the drill bit and the gauge diameter.

Figure 15 is a schematic view of the structure of the composite drill bit corresponding to the design of the tooth of Figure 14; Figure: 3211, the heart punch. Figure 16 is a plan view of the composite drill bit of Figure 15.

Fig. 17 is a schematic view showing the principle of the force transmitting mechanism of the structure shown in Fig. 1. In the force transmitting mechanism, the punch is fixedly coupled to the force transmitting rod, and the force transmitting rod forms a sliding connection with the anvil (sliding pair).

Figure 18 is a schematic view showing the principle of the force transmitting mechanism of the structure shown in Figure 5.

Figure 19 is a schematic view showing the principle of a force transmission mechanism according to the present invention. In the force transmission mechanism, the punch is fixedly connected with the force transmission rod, the force transmission rod and the anvil are connected by a hinge, and the force transmission rod and the bit body are disposed. There is a swinging slider, and the swinging slider is hinged with the force-transmitting rod, and the swinging slider is slidably connected with the bit body, that is, the swinging slider forms a connection between the force-transmitting rod and the bit body, which allows relative sliding and allows relative rotation. The force-transmitting rod and the punch can be slid relative to the bit body or can be rotated about the center of rotation of the swinging slider. In the picture: 328, swing slider.

Figure 20 is a swinging slider between the force transmission rod and the bit body of the force transmission mechanism shown in Figure 19, the swinging slider and the force transmission The structure of the rod is hinged, and the swinging slider is slidably connected with the bit body.

21 is a schematic diagram of the principle of a force transmission mechanism of the present invention, in which the punch is fixedly connected with the force transmission rod, the force transmission rod and the anvil are connected by a hinge, and the force transmission rod and the bit body are disposed. There is a swinging slider, and the swinging slider is slidably connected with the force transmitting rod, and the swinging slider is hinged with the bit body, and the force transmitting rod and the punch can slide relative to the bit body or rotate around the center of rotation of the swinging slider.

Figure 22 is a schematic view showing the structure of a force transmitting mechanism of the present invention, in which the transmission rod and the punch are consolidated, and the impact direction of the impact cutting structure is parallel to the direction of the bit axis.

Figure 23 is a schematic view showing the impact cutting teeth of the present invention using diamond as a surface-reinforced cemented carbide tooth. In the figure: 311, cemented carbide, 312, diamond reinforcement layer.

Fig. 24 is a schematic view showing the structure of a composite drill bit including an impact mechanism and adopting a one-piece structure. In the picture: 33, impact mechanism, 331, ram.

Figure 25 is a schematic view showing the structure of a composite drill bit including an impact mechanism and employing a split structure. In the figure: 5, impactor components, 51, impactor body, 52, hammer, 6, cutting structural components, 61, cutting structure body.

Figure 26 is a schematic view showing the structure of the spokes and the forceps when the spokes are connected to the bit body in order to prevent the rotation of the punch and the force transmission rod.

Fig. 27 is a schematic view showing the configuration of the anti-dropping step on the force-transmitting rod and the bit body in order to prevent the punch and the force-receiving rod from falling off. In the picture: 12, the bit body is prevented from falling off the steps, 3223, the force-transmitting rod is prevented from falling off the steps.

Figure 28 is a schematic view showing the structure of the composite drill bit in the runaway position.

detailed description

The following non-limiting examples are illustrative of the invention.

Example 1

As shown in FIG. 1 to FIG. 4, FIG. 10, FIG. 17, and FIG. 23, a scraping-impact composite drill bit includes a bit body 1, and the bit body 1 is provided with a fixed cutting structure 2, an impact cutting structure 3, and The hydraulic structure composed of the flow path 41 and the nozzle 42 includes a fixed cutting tooth 2 including a force transmitting mechanism 32 for transmitting an impact force and an impact cutting tooth 31, and the force transmitting mechanism 32 includes a punch 321 The force transmitting rod 322 and the anvil 323, the impact cutting teeth 31 are fixed on the punch 321 at the end of the force transmitting mechanism 32, and the punch 321 can slide relative to the bit body 1 in the direction of the impact force transmission. The composite drill bit does not include an impact mechanism, and has three fixed blades 22, three sets of impact cutting units, and fixed blades 22 and punches 321 disposed therebetween. A sealing device (such as the sealing ring 325 between the force transmitting rod 322 and the bit body 1 in FIG. 3) is disposed between the bit body 1 and the force transmitting mechanism 32. The fixed cutting teeth 21 and the impact cutting teeth 31 may respectively be polycrystalline diamond composite sheets, thermally stable polycrystalline diamond cutting teeth, natural diamond cutting teeth, impregnated diamond cutting blocks, impregnated diamond cutting teeth, cemented carbide cutting teeth, diamond Reinforced carbide cutting teeth, cubic boron nitride cutting teeth, ceramic cutting teeth, or cutting teeth containing diamond or cubic boron nitride, and other teeth similar to the various materials available on the drill bit. The tooth shape of the impact cutting teeth 31 may be a cone tooth, a wedge tooth, a ball tooth, a side wedge tooth, and a spoon tooth, or may be a tooth of other shapes having a good impact rock breaking effect. For thermally stable polycrystalline diamond, natural diamond, or impregnated diamond cutting teeth, in hard-to-drilled formations with high hardness, high plasticity, and high abrasiveness, high-tooth density is often used on fixed-cutting drills. Good fixed cutting teeth (such as polycrystalline diamond compacts, thermally stable polycrystalline diamond, natural diamond, or impregnated diamond cutting teeth) are placed on the bit body. Due to the high density of the teeth, the cutting teeth are limited to the depth of the formation, and the solid is solid. It is often difficult to cut the rock in the formation by cutting the teeth effectively, and the rock is broken by the grinding method with very low efficiency. Therefore, the heat stable polycrystalline diamond, natural diamond, or impregnated diamond cutting teeth are not suitable for the blade type. On the cutting structure. The invention combines the fixed cutting structure with the impact cutting structure, and the impact cutting tooth adopts the hard alloy tooth with good impact toughness or the surface-hardened cemented carbide tooth, which can obviously improve the depth of the fixed cutting tooth to enter the ground layer, This can reduce the density of the teeth of the fixed cutting teeth, so that the wear-resistant cutting teeth are applied to the fixed cutting structure (such as the blade-type fixed cutting structure) with a thinner tooth density, and the deep-cutting is performed with a larger eating depth. Broken rock. The above-mentioned priority method can significantly broaden the use range and use mode of the wear-resistant cutting teeth, and provide more efficient rock breaking means for the difficult-drilling formation. At this time, the well-wearing cutting teeth, combined with the impact teeth with good impact toughness, the combination of the two can significantly improve the drilling efficiency and the service life of the drill bit in the difficult-drilling formation. As shown in Fig. 23, the impact cutting teeth 31 on the punch 321 are made of diamond-hardened carbide teeth. The fixed cutting structure and the impact cutting structure are combined, that is, the impact cutting structure is added on the fixed cutting bit, and the impact of the impacting teeth on the rock is utilized to form a press-in pit or a crushing pit on the bottom surface of the well, so that the bottom of the well becomes Rugged. This can reduce the difficulty of the fixed cutting teeth to eat rock and the energy consumption of rock breaking, and improve the cooling effect of the fixed cutting teeth, thereby improving the rock breaking efficiency and service life of the fixed cutting bit, and broadening the bit's high abrasiveness and hardness. The use range of difficult to drill formations such as high heterogeneity. The impact cutting teeth 31 of the impact cutting structure 3 may be disposed within the radial coverage of the fixed cutting teeth 21 of the fixed cutting structure 2, or may be independently arranged (not overlapping the radial coverage of the cutting teeth of the fixed cutting structure), Or partially arranged independently. Preferably, the impact cutting teeth 31 and the fixed cutting teeth 21 are arranged in a radial overlapping manner, and the cutting teeth of the impact cutting structure 3 are arranged within a radial range other than one third of the radius of the drill bit (as shown in FIG. 10), generally When drilling in the common stratum, the crushing task in the core area of the drill bit is small and easy to be broken, while the crushing task in the area outside the core is relatively large, and the cutting teeth wear faster than the core, so the area outside the core is Arranging the impact cutting teeth facilitates the fracture of the corresponding area rock and slows the wear of the fixed cutting teeth. The punch 321 and the force transmitting rod 322 on the impact cutting structure 3 are fixed to each other as a fixed whole, and the force transmitting rod 322 is slidably coupled with the anvil 323 (the mechanism schematic is as shown in FIG. 17).

Example 2:

The embodiment is basically the same as the first embodiment, and the difference is that: there are two force-transmitting rods in one or each impact cutting unit, and the movement laws of the two force-transmitting rods are different, and there is relative motion between each other, wherein A force transmission rod (1) 3221 is fixedly connected with the punch 321 , and another force transmission rod ( 2 ) 3222 is hinged to the anvil 323 , and the two force transmission rods are connected by a hinge (as shown in FIGS. 5 and 18 ). . When the punch 321 is far from the center of the drill bit and its impact direction is larger than the axis of the drill bit, it is easier to realize the transition of the impact direction and the transmission of the impact force by using two mutually coupled force-transmitting rods. An anvil body sleeve 324 is disposed between the anvil 323 and the bit body 1 (as shown in FIG. 5 and FIG. 6), or the surface of the anvil body 323 directly forms a clearance fit with the inner hole of the bit body 1 to realize the anvil body. Relative sliding and centering positioning between the 323 and the bit body 1 (as shown in Figure 7).

Example 3:

This embodiment is basically the same as Embodiment 1 or Embodiment 2, and the difference is that the composite drill has two fixed blades 22, two sets of impact cutting units, and the fixed blades 22 and the punches 321 are arranged between each other (as shown in FIG. 8). ). The use of fewer fixed blades and impact cutting units facilitates the small size of the drill bit and facilitates the use of composite drill bits in small boreholes.

Example 4:

This embodiment is basically the same as Embodiment 1 or Embodiment 2, and the difference is: the fixed blade 22 and the punch of the composite drill bit The heads 321 are arranged asymmetrically. As shown in Fig. 9, the composite drill bit has three fixed blades 22, two sets of impact cutting units, and the fixed blades 22 and the punches 321 are arranged asymmetrically (partially in phase).

Example 5

This embodiment is basically the same as the above embodiment except that the impact cutting teeth 31 of the impact cutting structure 3 are arranged within a radial range other than one-half of the radius of the drill bit (as shown in Fig. 11).

Example 6:

This embodiment is basically the same as Embodiment 5 except that the impact cutting teeth 31 of the impact cutting structure 3 are arranged within a radial range other than two-thirds of the radius of the drill bit (as shown in Fig. 12). In general, the outer teeth of the fixed cutter bit (especially the area other than two-thirds of the drill radius) have a faster wear rate than the teeth in the core region. The rock breaking action of the impact cutter can break the fixed cutter in the region. As the rock efficiency is increased, the wear rate can be reduced, and the wear speed of the fixed cutting teeth in the core region and the outer region of the drill bit is close to the synchronization.

Example 7

This embodiment is basically the same as the above embodiment except that the impact cutting teeth 31 of the impact cutting structure 3 are arranged within a radial range within one third of the radius of the drill bit (as shown in Fig. 13). The center of the drill usually has an inner cone area. When drilling in a layer with high hardness and high brittleness, the impact cutting teeth are arranged close to the core of the drill bit, and the brittle fracture of the core rock is more easily caused by the impact of the impact cutting teeth. That is, the volume is broken, which is beneficial to improve the drilling efficiency of the drill bit.

Example 8

This embodiment is basically the same as the above embodiment, and the difference is that the impact cutting teeth 31 of the impact cutting structure 3 are arranged in the entire radial range except for a small portion such as the center of the drill bit and the gauge diameter (as shown in FIG. 14). As shown in Figs. 15 and 16, a center punch 3211 is provided near the center of the drill. In the difficult-drilling formation with high strength and plasticity, the impact cutting teeth are arranged in the entire radial range of the drill bit, which can increase the unevenness of the bottom rock in the entire radial region and improve the fixed cutting teeth in the entire radial range. The rock breaking efficiency and cooling effect improve the rock breaking efficiency and service life of the composite drill bit in such difficult-to-drill formations.

Example 9

This embodiment is basically the same as the above embodiment, and the difference is that the punch 321 is fixedly connected to the force transmission rod 322, the force transmission rod 322 is hingedly connected to the anvil body 323, and the swinging rod 322 and the bit body 1 are provided with a swinging slide. At block 328, the swinging slider 328 is hinged to the force transmitting rod 322, and the swinging slider 328 is slidably coupled to the bit body 1 (as shown in FIGS. 19 and 20), that is, the swinging lever 322 and the bit body 1 are oscillated by sliding 328. The block forms a connection that allows relative sliding and allows relative rotation. The force transmitting rod 322 and the punch 321 can either slide relative to the bit body 1 or rotate about the center of rotation of the swinging slider 328. When the impact direction of the punch 321 is larger than the axial direction of the drill bit, the introduction of the swing slider 328 can make the transmission of the impact force smoother.

Example 10

This embodiment is basically the same as the embodiment 9, except that, as shown in FIG. 21, the swinging slider 328 is slidably coupled to the force transmitting rod 322, and the swinging slider 328 is hinged to the bit body 1, the force transmitting rod 322 and the punching head 321 It is possible to slide relative to the bit body 1 or to rotate about the center of rotation of the swing slider 328. The effect of this embodiment is basically the same as that of the embodiment 9.

Example 11:

In this embodiment, the impact direction of the impact cutting structure is parallel to the bit axis direction. As shown in Figure 22, in Under this condition, the force transmitting mechanism 32 does not need a complicated structure, and only the force transmitting rod 322 is used to consolidate the punch 321 . Other technical solutions can be freely combined from the technical solutions of the specification or other embodiments as far as practicable by those skilled in the art.

Example 12:

This embodiment is basically the same as the above embodiment, and the difference is that the composite drill bit includes the impact mechanism 33, and the impact mechanism 33 and the bit body are of a unitary structure (as shown in Fig. 24). The impact force generated by the impact mechanism 33 when the drill bit is in operation acts on the anvil 323 of the force transmitting mechanism 32 through the hammer 331 on the impact mechanism 33. The one-piece construction makes the composite drill internal structure more compact and more reliable.

Example 13

This embodiment is basically the same as the embodiment 12, and the difference is that the bit body 1 adopts a split structure, and is connected by the impactor body 51 provided with the impact mechanism and the cutting structure body 61 provided with the fixed cutting structure 2 and the impact cutting structure 3. The impact mechanism is mounted on the hollow portion of the impactor body 51 to form the impactor member 5, and the fixed cutting structure 2, the impact cutting structure 3, and the cutting structure body 61 constitute the cutting structural member 6 (as shown in Fig. 25). The impact force generated by the impactor member 5 during the operation of the drill bit acts on the anvil body 323 of the force transmitting mechanism through the upper hammer 52 of the impact mechanism. The use of a split structure facilitates the manufacture and use of a composite drill bit, and the impactor component 5 and the cutting structural component 6 can be separately fabricated and assembled together prior to use in the well.

Example 14

In this embodiment, in order to prevent the rotation of the force transmission rod 322 and the punch 321 during the operation of the drill bit, an anti-rotation structure is provided between the punch 321 and the bit body 1 or between the force transmission rod 322 and the bit body 1. . As shown in Fig. 26, a spline connection is provided between the force transmitting rod 322 and the bit body 1 to prevent the force transmitting rod 322 and the punch 321 from rotating around the force transmitting rod shaft during operation.

Example 15

In the present embodiment, in order to prevent the dowel bar 322 and the punch 321 from coming off, an anti-drop structure is provided between the punch 321 and the bit body 1 or between the force transmission bar 322 and the bit body 1. As shown in Fig. 27, anti-dropping steps 3223 and 12 are provided on the force transmitting rod 322 and the bit body 1, respectively, in order to prevent the force-transmitting rod 322 and the punch 321 from coming off the bit under the pulling force.

Example 16:

In this embodiment, in order to prevent hammering of the anvil 323 by the hammer during the process of inserting the drill bit or lifting the drill bit, the composite drill bit is provided with an anti-air strike structure. As shown in Fig. 28, when the drill bit is not in contact with the bottom of the well, the anvil 323, the force transmitting rod 322, the punch 321 and the impact cutting teeth 31 in the impact cutting structure 3 will be together due to the action of gravity and the pressure difference between the internal and external circulating fluids. The downward sliding distance is such that the impact cutting teeth 31 protrude beyond the envelope contour surface of the cutting teeth 21 of the fixed cutting structure, and the position at which the impact cutting structure 3 is located is the anti-empty position. In this position, the runaway design of the impact mechanism enables the impact hammer in the impact mechanism to stop hammering the anvil to achieve no-load protection of the impact cutting structure.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

WO 2013/170788 Claim PCT/CN2013/075839

A scraping-impact composite drill bit comprising a bit body (1) and a fixed cutting structure (2) fixed to the bit body (1), characterized in that: the bit body (1) is further provided with The impact cutting structure (3), the impact cutting structure (3) includes a force transmitting mechanism (32) for transmitting an impact force and an impact cutting tooth (31), and the impact cutting tooth (31) is fixed at the end of the force transmitting mechanism (32) On the head (321), the punch (321) is capable of sliding or sliding impact with respect to the bit body (1) in the direction of impact force transmission.

2. A scraping-impact composite drill according to claim 1, wherein: the bit body (1) is further provided with an impact force generated by the force transmitting mechanism (32). Impact mechanism (33).

3. A scraping-impact composite bit according to claim 2, wherein: said bit body (1) adopts a split structure, and is composed of an impactor body (51) provided with said impact mechanism and The fixed structure (2) and the cutting structure body (61) of the impact cutting structure (3) are connected, and the impact mechanism is mounted on the hollow portion of the impactor body (51).

A scraping-impact compound drill according to claim 1 or 2 or 3, characterized in that the impact cutting teeth (31) are arranged in a radial region other than one third of the diameter of the drill bit.

A scraping-impact compound drill according to claim 1 or 2 or 3, characterized in that the impact cutting teeth (31) are arranged in a radial region other than one-half of the diameter of the drill bit.

A scraping-impact compound drill according to claim 1 or 2 or 3, characterized in that the impact cutting teeth (31) are arranged in a radial region other than two-thirds of the diameter of the drill bit.

A scraping-impact compound drill according to claim 1 or 2 or 3, characterized in that the impact cutting teeth (31) are arranged in a radial region within one third of the diameter of the drill bit.

8. A scraping-impact composite drill according to claim 1 or 2 or 3, wherein: said force transmitting mechanism (32) comprises an anvil body (323) and a force transmission rod (322) which are sequentially connected. And the punch (321), the relative sliding between the anvil (323) and the bit body (1), the relative sliding between the force transmitting rod (322) and the bit body (1), or by the swinging slider (328) A connection is formed which allows both relative sliding and relative rotation, the punch (321) being attached to the end of the force-transmitting rod (322) or forming an integral element with the force-transmitting rod (322).

9. A scraping-impact composite drill according to claim 8, wherein: in the same impact cutting unit, the number of the force transmission rods is one or more than one, and the number of the force transmission rods is large. At one time, the force transmission rods are connected to each other in series, and adjacent force transmission rods having relative motion with each other are connected by a hinge.

10. A scraping-impact composite drill according to claim 1 or 2 or 3, wherein: the fixed cutting teeth (21) on the fixed cutting structure (2) are polycrystalline diamond composite sheets, It can also be thermally stable polycrystalline diamond, natural diamond and impregnated diamond cutting teeth. The impact cutting teeth (31) on the impact cutting structure (3) are hard alloy teeth or hardened teeth with surface reinforcement.