A Punching Composite Drill Bit Suitable for Difficult-Drilling Formation

Abstract

The invention discloses a punching composite drill bit suitable for difficult-to-drill stratums. The drill bit comprises a drill bit body, blades and water holes or nozzles arranged in the drill bit body, wherein each blade is provided with a plurality of first cutting teeth, the tooth arranging face of each blade is provided with sockets for fixing the first cutting teeth, the drill bit body is further provided with punching structures and an impact force transmission mechanism, the punching structures are provided with punching teeth, and the body contour line of at least one blade and the body contour line of at least another blade are provided with at least one non-overlap area and at least one overlap point or area in a joint covering area. By the structure, the drill bit can work in an asynchronous cutting manner, the longitudinal abrasion length of the drill bit can be increased, the service life of the drill bit can be prolonged, the drill bit can be allowed to be in a high-specific-pressure drilling state during the whole drilling process, the rock drilling ability of the drill bit is enhanced, the drilling speed of the drill bit in the difficult-to-drill stratums is increased, and the service life of the drill bit in the difficult-to-drill stratums is prolonged.

Description

technical field [0001] The invention belongs to the technical equipment fields of petroleum and natural gas drilling engineering, mining engineering, building foundation engineering construction, geological drilling, tunnel engineering, hydrology, shield tunneling and non-excavation, and in particular relates to a drilling bit. Background technique [0002] Drill bits are rock-breaking tools used to break rocks and form wellbores in drilling engineering. Commonly used are PDC drill bits, roller cone bits and percussion drill bits. PDC bits rely on high hardness, wear-resistant, self-sharpening polycrystalline diamond composite sheets to shear and break rocks. PDC bits have high mechanical penetration rate, long life and low drilling cost in soft to medium hard formations. are widely used in. Existing fixed cutter bits represented by PDC bits usually have several blades, and multiple cutting elements are arranged on the blades along the radial direction of the bit (for PDC b...

AI Technical Summary

Problems solved by technology

[0009] The existing PDC bit with synchronous cutting principle is not only limited in drilling efficiency but also has a short service life when facing complex and difficult-to-drill formations (high hardness, high abrasiveness, even heterogeneous formations containing gravel layers, interlayers, etc.). ideal

The main reasons are as follows: First, in order to ensure that the drill bit has a strong ability to eat or penetrate the rock surface when drilling in hard formations, it is necessary to use cutting teeth with a small size (diameter), but the small diameter cutting teeth The exposed height is small, and the wearable height is significantly lower than that of the large-diameter cutter, but the wear speed of the cutter is faster at this time, thus forming an insoluble contradiction in the design of the drill bit for difficult-drilling formations: if the large-diameter cutter is used , the cutting teeth are difficult to penetrate into the rock (especially after a certain degree of wear), and the rock breaking efficiency of the drill bit is low; if the small diameter cutting teeth are used, the working life of the cutting teeth is not enough

Second, when the drill bit drills in hard formations and heterogeneous formations, the cutting teeth are often subjected to strong impact loads, and a small number or even individual cutting teeth are prone to rapid failure phenomena such as shedding, fracture, fragmentation, and cracking of the diamond layer. Once this phenomenon occurs, it will lead to the chain failure of the cutting teeth in the adjacent area due to the increase of the working load, and then the circumcision phenomenon, that is, the exposed part of the cutting teeth of the drill bit in the radial area is completely or mostly worn off. , and then grind out annular grooves on each blade body of the drill bit

Therefore, when the ring groove is worn out on the drill bit, it is generally considered that the drill bit has lost or is close to losing its cutting ability. Not only can it not be used in the well, but even repair (replacement or refurbishment of the worn cutting teeth) is difficult to implement in severe cases.

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