1. The utility model provides a directional bidentate self-balancing PDC drill bit suitable for soft or hard intermediate layer which characterized in that: the drill bit comprises a drill bit body (1), and blades (2) and nozzles (3) which are distributed on the drill bit body (1); the number of the blades (2) is 5, the blades (2) are provided with a double-tooth structure (4), a front row of single teeth (5), a rear row of conical teeth (6) and gauge teeth (7), and the rear row of conical teeth (6) are arranged behind the front row of single teeth (5) in the same track; the nozzles (3) are arranged in the crown straight line area and the crown circular arc area of each blade (2).

2. The directional double-tooth self-balancing PDC drill bit suitable for the soft and hard interlayer as claimed in claim 1, wherein: the crown part of the blade (2) is a straight-arc crown part, and the depth of the crown part cone is medium.

3. The directional double-tooth self-balancing PDC drill bit suitable for the soft and hard interlayer as claimed in claim 1, wherein: the lower part of the drill bit body (1) is a male connector, the lower end of the drill bit body is provided with a thread line, and the middle part of the drill bit body is provided with a groove convenient for buckling on the well.

4. The directional double-tooth self-balancing PDC drill bit suitable for the soft and hard interlayer as claimed in claim 1, wherein: every 5 cutting teeth of the front row of single teeth (5) are divided into 1 group and form 4 groups together, and a three-stage force balance structure for balancing the forces in the group, between the groups and the whole drill bit is formed.

5. The directional double-tooth self-balancing PDC drill bit suitable for the soft and hard interlayer as claimed in claim 1, wherein: the double-tooth structure (4) is formed by converting partial front row single teeth (5), a tangent line of a crown section line is made through a central point of the single teeth on a radial section, and the single teeth are expanded into the double-tooth structure (4) through setting a distance and an included angle.

Background

The invention belongs to the technical field of oil field drilling equipment, and particularly relates to a directional double-tooth self-balancing PDC drill bit suitable for a soft interlayer and a hard interlayer.

Disclosure of Invention

In order to solve the problems of large lateral force, poor drilling stability, low drilling efficiency and the like of a PDC drill bit in a soft and hard interlayer in the prior art, the invention provides a self-balancing PDC drill bit based on directional double teeth, which reduces the lateral force fluctuation of the drill bit in the soft and hard interlayer and improves the drilling stability of the drill bit.

The technical scheme adopted by the invention is as follows: a directional double-tooth self-balancing PDC drill bit suitable for a soft and hard interlayer comprises a drill bit body, and blades and nozzles distributed on the drill bit body; the number of the blades is 5, a double-tooth structure, a front row of single teeth, a rear row of conical teeth and gauge teeth are distributed on the blades, and the rear row of conical teeth are distributed behind the front row of single teeth in the same track; the nozzles are arranged in the crown linear area and the crown arc area of each blade.

Furthermore, the crown part of the blade is a straight-arc crown part, and the depth of the crown part cone is medium.

Furthermore, the lower part of the drill bit body is a male connector, the lower end of the drill bit body is provided with a thread line, and the middle part of the drill bit body is provided with a groove convenient for buckling on the well.

Furthermore, the self-balancing is a three-level force balance structure, every five cutting teeth of the front row of single teeth are divided into one group, four groups are formed by the same shape, parameters of circumferential angles of the blades, in the groups, between the groups and the blades are optimized, and the three-level force balance structure for balancing the integral forces of the drill bits, in the groups, between the groups and the drill bits is formed.

Furthermore, the directional double-tooth structure is formed by converting partial front row single teeth, specifically, a tangent line of a crown section line is made through a central point of the single tooth on a radial section, the single tooth is expanded into the double-tooth structure through setting a distance and an included angle, and the double-tooth structure only appears on the last two teeth of the odd number force balance group.

Further, the wing adopts the design of double with the orbit cutting teeth, the front row is conventional cylindrical compound piece, single tooth structure and double tooth structure have been arranged respectively, the double tooth structure only arranges in circular arc district crown, and arrange on 2 nd, 4 wing, the single tooth structural arrangement is on 1, 3, 5 wing, the back is arranged and is the toper cutting teeth, the toper tooth exposure height slightly is less than the front row tooth, this makes the depth that the front row tooth can restrict the stratum, and then effective control glues smooth vibration. The number of the nozzles is 8, and the nozzles are respectively arranged in a linear area and an arc area of each blade and used for flushing rock debris generated by the cutting teeth and cooling the cutting teeth.

Furthermore, the single-tooth structure gradually increases from the drill bit center to the direction back dip of the gauge protection area along the section of the crown part, so that the rock breaking efficiency is improved.

Furthermore, the force balance structure is a three-level force balance structure, specifically, every five conventional single teeth are divided into one group along the crown section from the drill bit center to the gauge protection end, and four force balance cutting tooth groups are formed by the groups. And optimizing tooth distribution parameters of each group of internal angles, groups of internal angles and circumferential angles to respectively form internal force balance, inter-group force balance and overall force balance of the drill bit, so that a three-level force balance structure is formed. The design can improve the drilling stability of the drill bit in a transition stratum (a soft and hard interlayer), and the cutting tooth groups of different groups cut different stratums respectively, so that the lateral force balance in the groups is kept, and the drilling stability can be kept among the cutting tooth groups even in different stratums.

Further, the tooth arrangement method of the directional double teeth comprises the following steps: and sequencing the force balance cutting tooth groups, arranging the double teeth at the corresponding positions of the last two single teeth of the odd number group, adjusting the angle and the distance, judging the interference of the tooth arrangement structure, and rejecting the last two teeth of the corresponding even number group. The double teeth are arranged at a certain interval and at a certain included angle, and the interval is very small, so that the stress zones generated by the double teeth can be effectively interfered and superposed, the stress peak value of the superposed zone is improved, the rock breaking efficiency is effectively improved, and the crushing zone is enlarged. The center of the double teeth generates a rock ridge with a certain width, and the rock ridge is beneficial to improving the stability of the drill bit and reducing the transverse vibration.

Furthermore, the directional double-tooth structure principle is that original single teeth are replaced by double-tooth structures with certain micro intervals and certain directional included angles, so that the directional double-tooth structure part is separated from a crown section and firstly contacts with a stratum in a hard stratum, a larger crushing area and prefabricated underground cracks are formed, the original rock stress is unloaded in advance, and the rock breaking efficiency of the single-tooth structure is improved. And because rock plasticity is stronger in softer stratum, the double teeth and the single teeth break rock together, and the rock breaking efficiency of the drill bit is also improved.

The invention has the beneficial effects that: the directional double-tooth self-balancing PDC drill bit is suitable for soft and hard staggered strata, and the stability and the rock breaking efficiency of the PDC drill bit in the soft and hard staggered strata can be improved. The unique directional double-tooth structure improves the rock breaking efficiency through stress interference superposition, enlarges a breaking area and promotes underground crack expansion, thereby improving the single-tooth rock breaking efficiency. The double-tooth part is separated from the crown section and contacts with the rock in advance in the hard formation, so that a larger crushing area is formed, the damage of crown cutting teeth is reduced, the impact wear of single teeth is reduced, and the rock breaking efficiency is improved; rock is broken with the monodentate cooperation in soft stratum, improves broken rock efficiency. The center of the double teeth has a rock ridge with a certain width generated at a certain interval, thereby reducing the transverse vibration of the drill bit and improving the stability of the drill bit. The three-level force balance structure ensures that the lateral force of the drill bit can not be increased rapidly even if the drill bit drills in a soft and hard interlayer and a heterogeneous stratum, thereby ensuring the drilling stability.

Drawings

FIG. 1 is a schematic front view of the first embodiment;

FIG. 2 is a schematic top view of the first embodiment;

FIG. 3 is a schematic perspective view of the first embodiment;

FIG. 4 is a schematic view of the radial teeth arrangement of the drill bit according to the first embodiment.

Detailed Description

Example one

Referring to the figures, the directional double-tooth self-balancing PDC drill bit suitable for the soft and hard interlayer comprises a drill bit body 1, blades 2 and nozzles 3, wherein the blades 2 and the nozzles are distributed on the drill bit body 1; the number of the blades 2 is 5, the blades 2 are provided with a double-tooth structure 4, a front row of single teeth 5, a rear row of conical teeth 6 and gauge teeth 7, and the rear row of conical teeth 6 are arranged behind the front row of single teeth 5 in the same track; the nozzles 3 are arranged in the crown straight line area and the crown arc area of each blade 2; the crown part of the blade 2 is a straight-arc crown part, and the depth of the crown part cone is medium; the lower part of the drill bit body 1 is a male connector, the lower end of the drill bit body is provided with a thread line, and the middle part of the drill bit body is provided with a groove convenient for being buckled on the well; the number of the nozzles 3 is 8.

And taking the horizontal blade on the right side as an initial blade, and respectively taking the blades from 1 st to 5 th along the anticlockwise direction. The double-tooth structure is formed by improving a front row of single teeth, the center coordinate, the double-tooth spacing and the double-tooth included angle of the front row of single teeth are adjusted, the radial arrangement of the double teeth is shown in fig. 4, a1, a2, b1, b2, c1, c2, d1 and d2 are double teeth after single teeth are converted, a1 represents a first tooth after the No. 4 single tooth in a circular arc area is converted into the double teeth, and a2 represents a second tooth after the No. 4 single tooth in the circular arc area is converted into the double teeth. Similarly, b1 represents the first tooth after the arc zone No. 5 single tooth is converted into double teeth, b2 represents the second tooth after the arc zone No. 5 single tooth is converted into double teeth; c1 represents the first tooth after the conversion from arc zone No. 14 single tooth to double tooth, c2 represents the second tooth after the conversion from arc zone No. 14 single tooth to double tooth; d1 represents the first tooth after conversion from single round sector number 15 to double, and d2 represents the second tooth after conversion from single round sector number 15 to double. Each tooth part of the double-tooth structure is separated from the profile of the crown part, so that the double-tooth structure firstly contacts with rock in a hard stratum and is crushed in advance to form a larger crushing area, the stress of the original rock is unloaded, the front row of single teeth of the crown part are protected, the initiation and the development of underground cracks are promoted, and the crushing efficiency of the front row of single teeth is improved. The nozzles are respectively arranged in a straight area and a circular arc area of the crown part of each blade, so that the rock debris is fully washed and the cutting teeth are cooled.

The back inclination angles of the cutting teeth on the radial section of the drill bit are gradually increased from the center of the drill bit to the diameter-keeping end, every five cutting teeth are divided into a group and are sequenced, the group is divided into an odd number group and an even number group, the double-tooth structure only appears on the last two teeth of the odd number group, and in order to avoid interference, the even number group rejects the corresponding front row of single teeth. Each cutting tooth group is optimized in turn angle inside the group, back dip angle between the groups and circumferential angle of the blades respectively to form a three-level force balance structure, and stability of drilling of the drill bit in the soft and hard interlayer is effectively improved.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.