A self-priming particle impact drill bit

Abstract

This invention belongs to the field of oil drilling equipment technology, specifically relating to a self-priming particle impact drill bit. The drill bit body has circumferentially distributed blades at its front end and a drill bit connector at its rear end. From rear to front, the drill bit body contains a suction nozzle, a mixing chamber, and an acceleration chamber. A central nozzle is located at the front end of the acceleration chamber, with a funnel-shaped bulge at its tip. A nose nozzle is located between the crown nose and the blades. A suction hole is formed on the body at the outlet of the suction nozzle. This three-stage suction-mixing-acceleration structure allows the drill bit to maximize the mixing of annular rock cuttings and drilling fluid within a limited space, enabling the jet to reach an effective jet velocity, thereby significantly improving the rock-breaking efficiency of the particle impact drill bit. The arrangement of the central nozzle and the nose nozzle allows the drill bit to fully utilize the impact effect of the particle jet, effectively releasing the original rock stress at the center and crown nose of the drill bit, thus avoiding or reducing wear and damage caused by stress concentration at these locations.

Description

Technical Field

[0001] This invention belongs to the field of oil drilling equipment technology, specifically relating to a self-priming particle impact drill bit. Background Technology

[0002] Particle impact drilling is a new and efficient drilling technology that has emerged in recent years. Unlike traditional drill bit and high-pressure water jet drilling, particle impact drilling uses surface pumps to deliver high-speed, hard spherical particles, forming a drilling rock-breaking method that primarily relies on impact fracturing, supplemented by high-speed hydraulic rock breaking and mechanical rock breaking by the drill bit. The advantage of this technology is that the high particle impact velocity can create instantaneous impact contact stress, thereby effectively improving the rock-breaking efficiency of hard and highly abrasive formations. However, this technology suffers from problems such as high cost of surface particle circulation equipment, severe particle erosion of the tubing, and low particle recovery rate.

[0003] Using near-bit tools to absorb annular rock cuttings for particle impact rock breaking has become a new option, but this method still has many drawbacks. First, the tools are usually small, making it difficult to accelerate the sucked-in rock cuttings to an effective impact velocity, resulting in poor rock breaking performance. Second, the fluid velocity of the sucked-in rock cuttings is low, making it difficult to mix fully with the high-speed drilling fluid at the center of the tool, causing particles to adhere to the inner wall of the drill string and resulting in uneven distribution of the particle-laden jet from each nozzle. Third, current particle impact tools are usually used in conjunction with conventional drill bits, and the resulting particle-laden jet cannot effectively release the stress of the original rock at the bottom of the well, resulting in a lack of significant acceleration effect. Summary of the Invention

[0004] To address the problems of low particle velocity, insufficient mixing with drilling fluid, and incompatibility between tools and drill bits in existing particle impact tools, this invention provides a self-priming particle impact drill bit to improve the rock-breaking efficiency of downhole self-priming particle impact drilling.

[0005] The technical solution adopted in this invention is as follows: a self-aspirating particle impact drill bit, wherein the front end of the drill bit body is provided with circumferentially distributed blades, the rear end is provided with a drill bit connector, and the drill bit body is provided with an intake nozzle, a mixing chamber and an acceleration chamber in sequence from back to front. The front end of the acceleration chamber is provided with a central nozzle, the front end of the central nozzle is a funnel-shaped expansion hole, the nose nozzle is located between the crown nose and the blades, and an intake hole is opened on the body at the outlet of the intake nozzle.

[0006] Furthermore, the inner wall of the middle section of the mixing chamber is provided with a ramp.

[0007] Furthermore, the crown surface of the cutter wing consists of a crown nose and a diameter-maintaining section. There is no cutter wing at the center of the drill bit. PDC cutting teeth are arranged on the cutter wing for cutting and breaking rocks.

[0008] Furthermore, the embryo of the self-aspirating particle impact drill bit has a three-stage structure of intake-mixing-acceleration.

[0009] Furthermore, the drill bit body is a barrel-shaped structure, the front cavity of the body is a flared horn, containing a central nozzle, with blades arranged at its front end, nose nozzles arranged between the blades, and suction holes for absorbing annular rock cuttings arranged at the front and rear of the drill bit body.

[0010] Furthermore, the suction nozzle is located at the rear end inside the drill bit, and an annular suction hole for connecting to the outside of the drill bit is provided at the nozzle outlet. The suction port on the outer wall of the drill bit body is located behind the cutter wing.

[0011] Furthermore, the mixing chamber is a mixing pipe with three ramps. The inner diameter of the three ramps gradually increases from front to back, and the lower slope of each ramp is greater than the upper slope, while the upper slope is gentler. Its function is to utilize the Kelvin-Helmholtz principle to cause the high-speed central drilling fluid jet generated by the suction nozzle to entrain the low-speed cuttings-containing fluid drawn in through the suction port, thereby improving the degree of particle mixing. The edge of the high-speed central jet first impacts the first ramp, generating a vortex under the action of the ramp, thus entraining and mixing with the low-speed cuttings-containing fluid, and producing jet divergence. The divergent jet further collides and entrains with the second and third flow channels, thereby significantly improving the mixing degree of cuttings particles and drilling fluid.

[0012] Furthermore, the central nozzle at the front end of the acceleration chamber is positioned at the center of the drill bit body, forming the main jet of the drill bit; the nose nozzle is positioned between the blades, causing the jet to act on the crown nose. The acceleration system accelerates the drilling fluid containing rock cuttings to an effective jet velocity within a limited space. When the drill bit is working, the jet formed by the central nozzle occupies the main part of the jet, which can form a larger breaking pit, effectively avoiding stress concentration damage caused by the small number of teeth in the center of traditional drill bits. The jet formed by the nose nozzle impacts the rock, causing breakage and micro-cracks, which can effectively release the original rock stress at the crown, reduce stress concentration at the crown nose, thereby reducing the wear of the PDC cutting teeth and improving the service life and rock breaking efficiency of the drill bit.

[0013] The beneficial effects of this invention: This invention provides a self-priming particle impact drill bit to improve the rock-breaking efficiency of downhole self-priming particle impact drilling. Its main advantages are as follows:

[0014] (1) The three-stage structure of suction-mixing-acceleration enables the drill bit to fully improve the mixing degree of annular rock cuttings and drilling fluid in a limited space, and to make the jet reach an effective jet velocity, thereby greatly improving the rock breaking efficiency of particle impact drill bit;

[0015] (2) The arrangement of the center nozzle and the nose nozzle enables the drill bit to fully utilize the impact effect of the particle jet, effectively release the original rock stress at the center of the drill bit and the crown nose, thereby avoiding or reducing the wear and damage caused by stress concentration at the center of the drill bit and the crown nose. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of Embodiment 1;

[0017] Figure 2 This is a cross-sectional schematic diagram of Embodiment 1;

[0018] Figure 3 This is a schematic diagram of the mixing chamber in Example 1. Implementation

[0019] Example

[0020] Referring to the figures, a self-priming particle impact drill bit is described. The drill bit body 1 has circumferentially distributed blades 3 at its front end and a drill bit connector 2 at its rear end. The drill bit body contains, from rear to front, a suction nozzle 7, a mixing chamber 8, and an acceleration chamber 9. The acceleration chamber 9 has a central nozzle 4 at its front end, with a funnel-shaped expansion hole at the front end. A nose nozzle 5 is located between the crown nose and the blades. A suction hole 6 is opened on the body at the outlet of the suction nozzle. A ramp 10 is provided on the inner wall of the middle section of the mixing chamber. The crown surface of the blades consists of a crown nose and a diameter-maintaining section. There are no blades at the center of the drill bit. PDC cutting teeth are arranged on the blades for cutting and breaking rocks. The self-priming particle impact drill bit has a three-stage structure: suction, mixing, and acceleration.

[0021] During drill bit operation, drilling fluid is ejected at high speed from the suction nozzle, creating a low-pressure field. Under the influence of this pressure difference, the annular fluid enters the drill bit through the suction port. The high-speed jet ejected from the suction nozzle and the low-speed cuttings-laden fluid drawn into the annulus undergo entrainment due to their different velocities and viscosities, initiating mixing. The high-speed jet then diverges and impacts the mixing chamber ramp, enhancing the entrainment effect. The cuttings-laden annular fluid is drawn into the jet center rather than adhering to the wall. The jet progressively diverges, entrains, and pressurizes through the mixing chamber ramp. The fully mixed jet then passes through the acceleration chamber, accelerating the drilling fluid to an effective impact velocity and distributing it to the center nozzle and nose nozzle. The jet from the center nozzle acts on the center of the drill bit, creating particle impact rock breaking. This reduces wear at the center of the drill bit, and the flared structure of the drill bit matrix helps form a core column of a certain height, thereby improving the lateral stability of the drill bit. The particle jet formed by the nose nozzle effectively releases the original rock stress of the crown nose rock, causing microcracks to reduce rock strength, improving rock breaking efficiency while reducing the wear of the crown nose cutting teeth.

[0022] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A self-priming particle impactor bit, characterized by: The front end of the drill bit matrix of the self-suction particle impact drill bit is provided with circumferentially distributed blades, the rear end is provided with a drill bit joint, the inside of the drill bit matrix is sequentially provided with a suction nozzle, a mixing chamber and an acceleration chamber from rear to front, the front end of the acceleration chamber is provided with a central nozzle, the front end of the central nozzle is a horn-shaped hole, the nose nozzle is located between the crown nose and the blade, and a suction hole is opened on the matrix at the outlet of the suction nozzle; The inner wall of the middle section of the mixing chamber is provided with a ramp, the mixing chamber is a mixing pipe with three ramps, the inner diameter of the three ramps gradually increases from front to rear, the lower slope of each ramp is greater than the upper slope, and the upper slope is relatively gentle. The embryo inside the self-suction particle impact drill bit is a three-section structure of suction-mixing-acceleration.

2. The self-priming particle impactor bit of claim 1, wherein: The crown surface of the blade is composed of a crown nose and a gauge section, and PDC cutting teeth are arranged on the blade.

Images