Self-renewing pdc bit with concave-convex profile cutting structure
By designing a PDC drill bit with a concave-convex profile cutting structure, the problem of low drilling efficiency of existing drill bits in hard formations has been solved. The drill bit has achieved downhole self-renewal, improving rock breaking efficiency and lifespan, especially with significant effects in hard formations.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CNPC GREATWALL DRILLING COMPANY
- Filing Date
- 2025-01-17
- Publication Date
- 2026-07-17
AI Technical Summary
Existing PDC drill bits have low drilling efficiency in hard and highly abrasive formations, and the cutting teeth are prone to failure, leading to rapid wear of the drill bits. In particular, drilling efficiency is low and vibration is common in hard-plastic formations, making it difficult to achieve effective downhole self-renewal.
Design a PDC drill bit with concave and convex profile cutting structures, including concave and convex profile cutting structures. The convex profile structure has higher aggression, can wear down quickly and form new cutting structures, realize downhole self-renewal, extend drill bit life, and assist in core collection through core holes.
It improves the rock-breaking efficiency of drill bits in hard formations, extends the service life of drill bits, and achieves self-renewal of drill bits by exposing the concave contour through the wear of the convex contour structure, thereby improving drilling speed and rock-breaking efficiency.
Smart Images
Figure CN122407080A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of drilling engineering technology, and in particular to a self-renewing PDC drill bit with a concave-convex profile cutting structure. Background Technology
[0002] Drill bits are tools that directly contact and break rocks during drilling, using cutting and impact to fracture them. PDC (Polycrystalline Diamond Compact) drill bits, as an important type of existing drill bit technology, are increasingly widely used in oil drilling, geology, and even construction engineering. PDC drill bits break rocks by cutting with PDC teeth, achieving ideal drilling speeds in soft to medium-hard formations, and are widely used in oil and gas drilling. Although PDC teeth have high hardness, their impact resistance and thermal wear resistance are limited. When drilling in hard formations, highly abrasive formations, or severely heterogeneous formations (interlayers of soft and hard materials, conglomerate layers, etc.), PDC drill bits are prone to rapid wear failure of the composite material. One of the most typical failure modes is impact chipping of the diamond layer in the composite material, which significantly reduces the cutting efficiency and service life of the drill bit. In particular, the tooth density in the core area of the drill bit is low; once a tooth fails, it can cause rapid failure of the core, even leading to "core removal" failure.
[0003] With the depletion of shallow oil and gas resources, the focus of oil and gas exploration and development has gradually shifted to deeper formations and the deep sea. Typically, the rock materials in deep formations are hard, highly abrasive, and poorly drillable. PDC drill bits often cannot achieve high rates of penetration in these formations, primarily due to limitations in the cutting teeth's engagement capacity. In particular, as formation depth increases, harder-plastic strata become more prevalent, hindering the effective engagement of the cutting teeth, resulting in low drilling efficiency and increased susceptibility to vibration, ultimately leading to rapid tooth failure.
[0004] The crown profile shape, also known as the cutting profile or profile, is a crucial structural feature of diamond drill bits. The crown profile line, also called the cutting profile line, macroscopically reflects the distribution and location of the cutting elements on the drill bit, and directly reflects the basic shape of the well bottom cut by the drill bit. The crown profile line of a diamond drill bit is typically a smooth, parabolic curve, comprising five parts: the inner cone, the crown tip (nose), the outer cone, the shoulder, and the gauge. When external loads cause the drill bit to tend to move horizontally, the rock wall of the inner or outer cone in the central region of the drill bit exerts a force opposite to its horizontal movement, thus suppressing lateral movement and improving drill bit stability. Assume there is a cutting plane (called the axial plane or axial surface passing through that point) on the drill bit, passing through the drill bit axis and a certain point on the drill bit. When the drill bit rotates around its own axis at zero drilling speed, the contour lines of the cutting elements intersect with the cutting plane or axial plane to form an intersection line. This intersection line is the axial contour line of the cutting element. The axial contour lines of all cutting elements are gathered together to form the bottom-hole cover map of the drill bit. In the bottom-hole cover map, an envelope curve tangent to the axial contour lines of all cutting elements can be drawn, called the drill bit cutting contour line. The drill bit cutting contour line reflects the basic shape characteristics of the bottom of the well drilled by the drill bit. The drill bit body contour line is the position curve of the drill bit body reflected in the bottom-hole cover map; it is an important characteristic curve of diamond drill bits. The drill bit tooth distribution surface refers to the curved surface formed by the intersection of the drill bit body and the drill bit body after rotating around the drill bit axis as the center of rotation and the drill bit body contour line as the radius of rotation for one revolution. In existing technologies, drilling speeds are slow in soft to medium-hard formations, while in hard formations, rapid PDC failure results in low mechanical drilling speeds. How to achieve self-renewal of the drill bit cutting structure without affecting the drill bit's drilling performance is a bottleneck problem related to drill bit failure.
[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention
[0006] The purpose of this invention is to provide a self-renewing PDC drill bit with a concave-convex profile cutting structure, which enables rapid drilling. When the convex profile cutting structure wears or even fails, the concave profile can be quickly exposed to form a new cutting structure, thereby achieving downhole self-renewal of the drill bit, improving rock breaking efficiency, and extending the service life of the drill bit.
[0007] To achieve the above objectives, the present invention provides the following technical solution:
[0008] A self-renewing PDC drill bit with a concave-convex profile cutting structure according to the present invention includes:
[0009] Drill bit body;
[0010] A concave profile cutting structure is arranged on the crown of the drill bit body and protrudes outward. The concave profile cutting structure is concave inward relative to the horizontal plane towards the drill bit body and is provided with a plurality of first PDC cutting teeth.
[0011] A convex profile cutting structure is arranged on a concave profile cutting structure and protrudes outward. The convex profile cutting structure protrudes away from the drill bit base relative to the horizontal plane and is provided with multiple second PDC cutting teeth. An annular space is formed between the convex profile cutting structure and the concave profile cutting structure.
[0012] The core hole is located at the center of the convex profile cutting structure.
[0013] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, the concave profile cutting structure includes a plurality of first blades spaced apart on the crown of the drill bit body, the first blades being concave inward relative to the horizontal plane toward the drill bit body.
[0014] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, a plurality of first blades are symmetrically distributed relative to the central axis of the drill bit body and the plurality of first blades extend toward the central axis without converging.
[0015] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, the first blade has a wavy shape in the radial direction of the drill bit.
[0016] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, the convex profile cutting structure includes a plurality of second blades spaced apart on the concave profile cutting structure, the second blades protruding relative to the horizontal plane in a direction away from the drill bit body.
[0017] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, multiple second blades are symmetrically distributed relative to the central axis of the drill bit body, and the multiple second blades extend toward the central axis and converge, with the core hole passing through the convergence position.
[0018] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, the second blade has a wavy shape in the radial direction of the drill bit.
[0019] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, the diameter of the first PDC cutting tooth is larger than the diameter of the second PDC cutting tooth.
[0020] The self-renewing PDC drill bit with a concave-convex profile cutting structure is a centrally symmetrical structure.
[0021] In the self-renewing PDC drill bit with a concave-convex profile cutting structure, the first PDC cutting tooth or the second PDC cutting tooth includes a planar tooth, an axe-shaped tooth, a conical tooth, a concave tooth, or a triangular tooth.
[0022] In the above technical solution, the self-renewing PDC drill bit with a concave-convex profile cutting structure provided by the present invention has the following beneficial effects: During drilling, the convex profile cutting structure of the self-renewing PDC drill bit with a concave-convex profile cutting structure has a higher attack on the formation, enabling rapid drilling. When the convex profile cutting structure wears or even fails, the concave profile can be quickly exposed to form a new cutting structure, realizing downhole self-renewal of the drill bit, improving rock breaking efficiency while extending the service life of the drill bit; the setting of the core hole can realize the formation of large rock blocks at the bottom of the well, which is beneficial to the collection and measurement of geological data. In addition, the rock core column formed by the convex profile cutting is more easily broken by the cutting teeth on the concave cutting structure, resulting in higher rock breaking efficiency; the wavy cutting structure shape extends the tooth distribution line of the cutting teeth, which can increase the tooth distribution density; the shape of the wavy cutting structure changes the front-to-back sequence of the cutting teeth in the circumferential direction on the same structure, which can increase the rock breaking effect. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.
[0024] Figure 1 This is a schematic diagram of a self-renewing PDC drill bit with a concave-convex profile cutting structure, provided as an embodiment of the present invention.
[0025] Figure 2 This is a schematic diagram of the bottom cover of a self-renewing PDC drill bit with a concave-convex profile cutting structure, provided as an embodiment of the present invention.
[0026] Figure 3 This is a schematic diagram of the core hole structure of a self-renewing PDC drill bit with a concave-convex profile cutting structure, provided as an embodiment of the present invention.
[0027] Figure 4 for Figure 3 A top view schematic diagram of a self-renewing PDC drill bit with a concave-convex profile cutting structure provided in one embodiment of the present invention.
[0028] Figure 5 This is a schematic diagram illustrating the formation of a core column when a self-renewing PDC drill bit with a concave-convex profile cutting structure is provided with a core-receiving hole, according to an embodiment of the present invention.
[0029] Figure 6 This is a schematic diagram of a self-renewing PDC drill bit with a concave-convex profile cutting structure, provided as an embodiment of the present invention. The convex profile cutting structure is wavy.
[0030] Explanation of reference numerals in the attached figures:
[0031] 1. Drill bit body; 2. Concave profile cutting structure; 3. Convex profile cutting structure; 4. Nozzle; 5. Core hole; 6. First PDC cutting tooth; 7. Second PDC cutting tooth; 8. Core column; 9. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that similar reference numerals and letters in the following drawings indicate similar items. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.
[0034] See Figure 1-6 As shown, in one embodiment, a self-renewing PDC drill bit with a concave-convex profile cutting structure according to the present invention includes,
[0035] Drill bit body 1;
[0036] A concave profile cutting structure 2 is arranged on the crown of the drill bit body 1 and protrudes outward. The concave profile cutting structure 2 is concave inward relative to the horizontal plane towards the drill bit body 1 and is provided with a plurality of first PDC cutting teeth 6.
[0037] A convex profile cutting structure 3 is arranged on a concave profile cutting structure 2 and protrudes outward. The convex profile cutting structure 3 protrudes away from the drill bit base relative to the horizontal plane and is provided with a plurality of second PDC cutting teeth 7. An annular space is formed between the convex profile cutting structure 3 and the concave profile cutting structure 2.
[0038] The core hole 5 is located at the center of the convex profile cutting structure 3.
[0039] Furthermore, it also includes,
[0040] Nozzle 4 is located at the crown of the drill bit body.
[0041] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, the concave profile cutting structure 2 includes a plurality of first blades spaced apart on the crown of the drill bit body, the first blades being concave inward relative to the horizontal plane toward the drill bit body.
[0042] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, a plurality of first blades are symmetrically distributed relative to the central axis of the drill bit body and the plurality of first blades extend toward the central axis without converging.
[0043] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, the first blade has a wavy shape in the radial direction of the drill bit.
[0044] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, the convex profile cutting structure 3 includes a plurality of second blades spaced apart from the concave profile cutting structure 2, the second blades protruding relative to the horizontal plane in a direction away from the drill bit body.
[0045] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, a plurality of second blades are symmetrically distributed relative to the central axis of the drill bit body and the plurality of second blades extend toward the central axis and converge, with the core hole 5 passing through the convergence position.
[0046] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, the second cutter blade has a wavy shape in the radial direction of the drill bit.
[0047] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, the diameter of the first PDC cutting tooth 6 is larger than the diameter of the second PDC cutting tooth 7.
[0048] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, the self-renewing PDC drill bit with a concave-convex profile cutting structure has a centrally symmetrical structure.
[0049] In a preferred embodiment of the self-renewing PDC drill bit with a concave-convex profile cutting structure, the first PDC cutting tooth 6 or the second PDC cutting tooth 7 includes planar teeth, axe-shaped teeth, conical teeth, concave teeth, or triangular teeth.
[0050] In one embodiment, a self-renewing PDC drill bit with concave-convex profile cutting structures includes a drill bit body and a nozzle 4. A concave profile cutting structure 2 is provided on the drill bit body, and a convex profile cutting structure 3 is provided on the concave profile cutting structure 2, with an annulus formed between the concave and convex profile cutting structures 3. In the bottom hole coverage pattern, both the concave profile cutting structure 2 and the convex profile cutting structure 3 can achieve full coverage of the bottom hole, enabling full-size drilling. The convex profile cutting structure 3 refers to a structure that bulges downwards relative to the horizontal plane when the drill bit is vertically facing downwards, forming a cone shape; conversely, the concave profile cutting structure 2 is the opposite. During drilling, the convex profile cutting structure 3 has a higher attack power on the formation, enabling rapid drilling, especially in soft formations. When drilling in hard formations, if the convex profile cutting structure 3 wears down or even fails, the concave profile can be quickly exposed, forming a new cutting structure, achieving downhole self-renewal of the drill bit, improving rock-breaking efficiency while extending the drill bit's service life. The bottom hole cover tooth layout diagram refers to the diagram where the cutting profiles of the cutting teeth rotate around the drill bit centerline in any axial plane passing through the drill bit centerline, forming an intersection line with that axial plane. This intersection line is the cutting profile line. The bottom hole cover tooth layout diagram directly reflects important parameters such as the positioning radius and positioning height of the cutting teeth.
[0051] As a preferred embodiment of the present invention, a core-receiving hole 5 is provided at the center of the convex profile cutting structure 3. The core-receiving hole 5 enables the formation of large rock blocks at the bottom of the well, which is beneficial for the collection and measurement of geological data and the acquisition of strata lithology information. In addition, the rock core column formed by the convex profile cutting releases the constraints of the surrounding rock, making it easier to be broken by the cutting teeth on the concave cutting structure, resulting in higher rock-breaking efficiency. The convex profile cutting structure 3 has a wavy shape in the radial direction of the drill bit. The wavy shape of the cutting structure extends the tooth distribution line of the cutting teeth, which can increase the tooth distribution density. In addition, the wavy shape changes the front-to-back sequence of the cutting teeth in the circumferential direction on the same structure, which can increase the rock-breaking effect. The connection methods between the convex profile cutting structure 3 and the concave profile cutting structure 2 include screws, pins, threads, welding, and integral molding.
[0052] In one embodiment, a self-renewing PDC drill bit with a concave-convex profile cutting structure includes a drill bit body 1 and a nozzle 4. A concave profile cutting structure 2 is provided on the drill bit body 1, and a convex profile cutting structure 3 is provided on the concave profile cutting structure 2. An annular space is formed between the concave and convex profile cutting structures.
[0053] Please see Figure 2In the wellbore coverage diagram, both the concave profile cutting structure 2 and the convex profile cutting structure 3 can achieve full coverage of the wellbore, enabling full-size drilling. The convex profile cutting structure 3 protrudes downwards relative to the horizontal plane, forming a cone shape, while the concave profile cutting structure 2 is concave relative to the horizontal plane. During drilling, the convex profile cutting structure 3 has a higher attack power on the formation, enabling rapid drilling, especially in soft formations. When drilling in hard formations, if the second PDC cutting tooth 7 on the convex profile cutting structure 3 wears or even fails, the concave profile cutting structure 2 can be quickly exposed, forming a new cutting structure. This achieves downhole self-renewal of the drill bit, improving rock-breaking efficiency while extending the drill bit's service life.
[0054] Please see Figure 3-5 A core-receiving hole 5 is located at the center of the convex profile cutting structure 3. The core-receiving hole 5 enables the formation of large rock blocks at the bottom of the well, which is beneficial for obtaining formation information. Furthermore, the core column 51 formed by the convex profile cutting structure 3 releases the constraints of the surrounding rock, making it easier for the first PDC cutting tooth 6 on the concave profile cutting structure 2 to break, resulting in higher rock-breaking efficiency. (See also...) Figure 6 The convex profile cutting structure 3 has a wavy shape in the radial direction of the drill bit, and the second PDC cutting teeth 7 are distributed on it in a wavy shape.
[0055] In one embodiment, a reinforcing portion is provided at the connection between the concave profile cutting structure 2 and the convex profile cutting structure 3, and further, the reinforcing portion is provided with PDC cutting teeth.
[0056] In one embodiment, the annular space is directly below the core hole 5.
[0057] Finally, it should be noted that the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0058] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.
Claims
1. A self-renewing PDC drill bit with a concave-convex profile cutting structure, characterized in that, It includes, Drill bit body; A concave profile cutting structure is arranged on the crown of the drill bit body and protrudes outward. The concave profile cutting structure is concave inward relative to the horizontal plane towards the drill bit body and is provided with a plurality of first PDC cutting teeth. A convex profile cutting structure is arranged on a concave profile cutting structure and protrudes outward. The convex profile cutting structure protrudes away from the drill bit base relative to the horizontal plane and is provided with multiple second PDC cutting teeth. An annular space is formed between the convex profile cutting structure and the concave profile cutting structure. The core hole is located at the center of the convex profile cutting structure.
2. The self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 1, characterized in that, The concave profile cutting structure includes a plurality of first blades spaced apart on the crown of the drill bit body, the first blades being concave inward relative to the horizontal plane toward the drill bit body.
3. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 2, characterized in that, Multiple first blades are symmetrically distributed relative to the central axis of the drill bit body, and the multiple first blades extend toward the central axis without converging.
4. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 2, characterized in that, The first blade has a wave-shaped structure in the radial direction of the drill bit.
5. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 1, characterized in that, The convex profile cutting structure includes a plurality of second blades spaced apart on the concave profile cutting structure, the second blades protruding relative to the horizontal plane in a direction away from the drill bit body.
6. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 5, characterized in that, Multiple second blades are symmetrically distributed relative to the central axis of the drill bit body, and the multiple second blades extend toward the central axis and converge, with the core hole passing through the convergence position.
7. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 5, characterized in that, The second blade has a wave-shaped structure in the radial direction of the drill bit.
8. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 1, characterized in that, The diameter of the first PDC cutting tooth is greater than the diameter of the second PDC cutting tooth.
9. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 1, characterized in that, The self-renewing PDC drill bit with a concave-convex profile cutting structure has a centrally symmetrical structure.
10. A self-renewing PDC drill bit with a concave-convex profile cutting structure according to claim 1, characterized in that, The first PDC cutting tooth or the second PDC cutting tooth includes flat teeth, axe-shaped teeth, conical teeth, concave teeth, or triangular teeth.