WO2023005108A1

WO2023005108A1 - Directional double-tooth self-balancing pdc bit suitable for soft and hard interlayer

Info

Publication number: WO2023005108A1
Application number: PCT/CN2021/137798
Authority: WO
Inventors: 李玮; 盖京明; 董家盼; 李卓伦; 焦圣杰
Original assignee: 东北石油大学
Priority date: 2021-07-29
Filing date: 2021-12-14
Publication date: 2023-02-02
Also published as: CN113404436A; CN113404436B

Abstract

The present invention relates to the technical field of oil field drilling equipment, and particularly relates to a directional double-tooth self-balancing PDC bit suitable for a soft and hard interlayer. The bit comprises a bit body, and blades and nozzles arranged on the bit body; five blades are provided, a double-tooth structure, front-row single teeth, rear-row conical teeth, and gauge teeth are arranged on each blade, and the rear-row conical teeth are arranged behind the front-row single teeth on the same track; the nozzles are arranged on crown straight areas and arc areas of the blades; the crown of the blade is a straight-arc crown, and the cone depth of the crown is moderate; the lower part of the bit body is a male connector, threads are formed at the lower end, and a groove that facilitates in-well fastening is lathed at the middle. Single-tooth impact wear is reduced and rock breaking efficiency is improved.

Description

A directional double-tooth self-balancing PDC drill bit suitable for soft and hard interlayers

technical field

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

Background technique

PDC bit is currently the main drilling tool for oil and gas exploration and development. It has become the main tool for rock breaking as early as 10 years ago and plays an important role in the oil drilling industry. As my country's oil and gas exploration and development shift to deep and unconventional formations, problems such as complex geological conditions, hard formations, poor drillability, low ROP, and long drilling cycles are particularly prominent. At the same time, due to insufficient drilling energy at the bottom of the hole, the PDC bit is usually accompanied by different types of vibration during the drilling process, among which lateral vibration is the most destructive type of vibration, which may cause the bit to rotate, resulting in instantaneous failure of the bit and causing the bit early damage. Lateral vibration is usually caused by unbalanced tooth design and formation heterogeneity, especially in the transitional formation of soft and hard interlayers, due to the different mechanical parameters of the cutting teeth breaking rock, which usually leads to large lateral vibration of the drill bit. force fluctuations. Aiming at the above design requirements, a self-balancing PDC bit based on directional double teeth is designed to improve the drilling stability and rock-breaking efficiency of the bit in formations with many soft and hard interlayers.

Contents of the invention

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

The technical solution adopted in the present invention is: a directional double-tooth self-balancing PDC drill bit suitable for soft and hard interlayers, the drill bit includes a drill body and blades and nozzles arranged on the drill body; the number of blades is 5 The blades are equipped with a double-tooth structure, a front row of single teeth, a rear row of conical teeth and gauge teeth, and the rear row of conical teeth are arranged on the same track behind the front row of single teeth; the nozzles are arranged on each blade The crown straight line area and arc area.

Further, the crown of the blade is a straight-arc crown, and the taper depth of the crown is moderate.

Further, the lower part of the drill bit body is a male joint, and the lower end is provided with a screw thread, and the middle part is provided with a groove for making uphole make-up.

Furthermore, the blade is designed with double rows of cutting teeth on the same track, and the front row is a conventional cylindrical composite sheet, which is respectively arranged with a single-tooth structure and a double-tooth structure. On blades 2 and 4, the single-tooth structure is arranged on

blades

1, 3, and 5, and the rear row is arranged as conical cutting teeth. The depth of the row of teeth eating into the formation can effectively control the stick-slip vibration. There are 8 nozzles in total, which are respectively arranged in the straight line area and the arc area of each blade to wash away the cuttings produced by the cutting teeth and cool down the cutting teeth.

Furthermore, the single-tooth structure gradually increases the back-dip angle from the center of the drill bit to the gauge area along the crown section, so as to improve the rock-breaking efficiency.

Further, the force balance structure is a three-stage force balance structure, specifically, every five conventional single teeth are divided into groups along the crown section from the center of the drill bit to the gauge end, forming four force balance cutting tooth groups in total. The parameters of tooth layout are optimized for each group, between groups and circumferential angles to form the force balance within the group, the force balance between groups and the overall force balance of the drill bit, thus forming a three-level force balance structure. This design can improve the drilling stability of the drill bit in transitional formations (soft and hard interlayers). Different groups of cutting teeth cut different formations, so that the lateral force balance is maintained within the group. Even if the cutting teeth groups are in different It can also maintain drilling stability in the formation.

Further, the tooth arrangement method of the directional double teeth is as follows: sort the above-mentioned force-balanced cutting tooth groups, only arrange the double teeth at the corresponding positions of the last two single teeth of the odd group, adjust the angle and distance, and carry out the interference of the tooth arrangement structure Judgment, the last two teeth of the corresponding even group are removed. The double teeth are arranged at a certain interval and included angle. The distance is very small, so that the stress area generated by the double teeth can effectively interfere and superimpose, thereby increasing the stress peak value in the superimposed area, effectively improving the rock breaking efficiency and expanding the crushing area. The center of the double tooth produces a rock ridge with a certain width, which is beneficial to improve the stability of the drill bit and reduce lateral vibration.

Furthermore, the principle of the directional double-tooth structure is to replace the original single-tooth structure with a double-tooth structure with a certain small spacing and a certain directional angle, which makes the directional double-tooth structure partly separated from the crown section, and first contacts the formation in hard formations. In this way, a large crushing area and prefabricated underground cracks are formed, and the stress of the original rock is unloaded in advance, thereby improving the rock breaking efficiency of the single-tooth structure. In soft formations, due to the strong rock plasticity, double teeth and single teeth work together to break rock, which also improves the rock breaking efficiency of the drill bit.

The beneficial effects of the present invention: the directional double-tooth self-balancing PDC drill bit is suitable for soft and hard formations, and can improve the stability and rock breaking efficiency of the PDC drill bit in the soft and hard formations. The unique directional double-tooth structure improves the rock-breaking efficiency through stress interference superposition, expands the crushing area and promotes the expansion of underground cracks, thereby improving the single-tooth rock-breaking efficiency. The part of the double tooth breaks away from the crown section, and contacts the rock in advance in the hard formation, thereby forming a larger crushing zone and reducing the damage of the crown cutter, reducing the impact wear of the single tooth, and improving the rock breaking efficiency; in the soft formation and single Teeth work together to break rock, improving rock breaking efficiency. There is a certain distance between the centers of the double teeth to generate a rock ridge with a certain width, thereby reducing the lateral 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 will not increase sharply even when the drill bit is drilling in soft and hard interlayers and heterogeneous formations, thereby ensuring drilling stability.

Description of drawings

Fig. 1 is the front view structure schematic diagram of embodiment one;

Fig. 2 is the top view structural representation of embodiment one;

Fig. 3 is the three-dimensional structure schematic diagram of embodiment one;

Fig. 4 is a schematic diagram of the radial arrangement of teeth of the drill bit in the first embodiment.

Detailed ways

Embodiment one

With reference to each figure, a kind of directional double-teeth self-balancing PDC drill bit suitable for soft and hard interlayers, the drill bit includes a drill body 1 and blades 2 and nozzles 3 arranged on the drill body 1; the number of blades 2 is 5, the blade 2 is equipped with a double-tooth structure 4, a front row of single teeth 5, a rear row of conical teeth 6 and a gauge tooth 7, and the rear row of conical teeth 6 is arranged on the same track behind the front row of single teeth 5; The nozzles 3 are arranged in the straight line area and the arc area of the crown of each blade 2; the crown of the blade 2 is a straight line-arc crown, and the cone depth of the crown is moderate; the drill body 1 The lower part is a male joint, and the lower end is provided with a screw thread, and the middle car has a groove for making up the well; the number of the nozzles 3 is 8.

Take the right horizontal blade as the initial blade, and the blades in the counterclockwise direction are the 1st to 5th blades respectively. The double-tooth structure is improved from the front single-tooth, and the center coordinates, double-tooth spacing and double-tooth included angle of the front-to-single-tooth are adjusted. , c1, c2, d1 and d2 are the double teeth converted from single teeth, a1 represents the first tooth after the No. 4 single tooth in the circular arc area is transformed into a double tooth, a2 represents the No. It is the second tooth after the double tooth. Similarly, b1 represents the first tooth after the No. 5 single tooth in the circular arc area is converted into a double tooth; b2 represents the second tooth after the No. 5 single tooth in the circular arc area is transformed into a double tooth; The first tooth after the No. 14 single tooth in the arc area is converted into a double tooth; c2 indicates the second tooth after the No. 14 single tooth in the arc area is transformed into a double tooth; d1 indicates the No. 15 single tooth in the arc area The first tooth after being transformed into a double tooth, and d2 represents the second tooth after the No. 15 single tooth in the arc zone is transformed into a double tooth. Each tooth part of the double-tooth structure is separated from the crown section, so that the double-tooth structure first contacts the rock in the hard formation, and is pre-broken to form a larger crushing zone, unloading the stress of the original rock, protecting the single tooth in the front row of the crown, and promoting the initiation of underground cracks And development, so as to improve the crushing efficiency of the front single tooth. The nozzles are respectively arranged in the straight line area and the arc area of the crown of each blade, so as to fully wash the cuttings and cool the cutting teeth.

From the center of the drill bit to the gauge end, the back rake angle of the cutting teeth on the radial section of the drill bit gradually increases, and every five groups are divided into groups and sorted, divided into odd groups and even groups, and the double-tooth structure only appears in odd groups. On the last two teeth, in order to avoid interference, the even group will remove the corresponding front row single tooth. Each cutting tooth group is optimized for inner rotation angle, inter-group back rake angle and blade circumferential angle to form a three-level force balance structure, which effectively improves the drilling stability of the drill bit in soft and hard interlayers.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims

A directional double-tooth self-balancing PDC drill bit suitable for soft and hard interlayers, characterized in that: the drill bit includes a drill body (1) and a blade (2) and a nozzle (3) arranged on the drill body (1); The number of the blades (2) is 5, and the blades (2) are equipped with a double tooth structure (4), a front row of single teeth (5), a rear row of conical teeth (6) and gauge teeth (7 ), the rear row of conical teeth (6) are arranged on the same track behind the front row of single teeth (5); the nozzles (3) are arranged on the crown straight line area and arc area of each blade (2).
A directional double-tooth self-balancing PDC drill bit suitable for soft and hard interlayers according to claim 1, characterized in that: the crown of the blade (2) is a straight-arc crown, and the cone depth of the crown is moderate.
A directional double-tooth self-balancing PDC drill suitable for soft and hard interlayers according to claim 1, characterized in that: the lower part of the drill body (1) is a male joint, and the lower end is provided with a thread, and the middle part is provided with a convenient The groove of the well.
A directional double-tooth self-balancing PDC drill suitable for soft and hard interlayers according to claim 1, characterized in that: the self-balancing is a three-stage force balance structure, and the front row of single teeth (5) every five The three cutting teeth are divided into one group, forming four groups in total, and the parameters are optimized within the group, between the groups and the circumferential angle of the blade (2), forming a three-level force balance structure of the internal force balance among the groups, between the groups and the overall force of the drill bit.
The directional double-tooth self-balancing PDC drill suitable for soft and hard interlayers according to claim 1, characterized in that: the directional double-tooth structure (4) is transformed from a part of the front row of single teeth (5), specifically In order to make a tangent to the section line of the crown through the center point of the single tooth on the radial section, the single tooth is expanded into a double-tooth structure by setting the spacing and angle (4). The double tooth structure (4) only appears on the last two teeth of the odd force balance group.