Fast core drill bit

Abstract

The present invention relates to the technical field of coring drill bits, and is a fast-coring coring drill bit, which includes a coring outer barrel, a drill bit body being connected to the outer side of the lower end of the coring outer barrel by a thread, a blade being fixedly installed along the circumference of the outer side of the lower end of the drill bit body, PDC teeth of different sizes being fixedly installed on the outer side of the blade, and a coring inner barrel being provided inside the coring outer barrel. The present invention has a reasonable and compact structure and is easy to use. By setting PDC teeth of different sizes, the advantages of large and small teeth complement each other, and can take into account the intrusion ability, aggressiveness and rock breaking efficiency of the coring drill bit, improve the working stability of the coring drill bit, extend the service life of the drill bit, improve the guiding ability of the drill bit, and enhance the formation adaptability of the coring drill bit, especially the drilling performance of soft and hard interlaced formations. By setting a connecting short section and a guide head that are easy to disassemble at the lower end of the coring inner barrel and the inner barrel short section, the coring can be quickly performed, and the invention has the characteristics of safety, labor saving, simplicity and high efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of coring drill bits, in particular to a fast-coring type coring drill bit. Background Art

[0002] Currently, PDC drill bits are one of the most commonly used rock-breaking tools in oil and gas coring operations. PDC drill bits are typically designed with blades, with PDC teeth positioned on the blade crowns of the drill bit body. The blades form hydraulic channels within the drill bit. PDC teeth are composed of a polycrystalline diamond layer and a carbide base. The polycrystalline diamond layer possesses the high hardness and wear resistance of diamond, but also exhibits a degree of brittleness. PDC teeth are generally cylindrical in shape. During rock-breaking operation, the bit is pressed into (invaded) the formation by the weight on bit (WOB). The rotation of the drill bit then scrapes and breaks the rock. Generally speaking, the smaller the PDC tooth size (referring to the diameter of the cylinder), the easier it is to penetrate the formation. However, smaller PDC tooth size reduces the amount of rock scraping and the tooth coverage area is also reduced. Therefore, when drilling in softer formations, larger PDC teeth are generally used to increase the amount of rock scraping and breaking by the PDC teeth, thereby improving the drilling efficiency of soft formations; when drilling in hard formations, smaller PDC teeth are generally used to enhance the ability and depth of the PDC teeth to penetrate the formation, thereby increasing the drilling speed.

[0003] Due to the brittleness of the polycrystalline diamond layer of PDC cutters, large-sized PDC cutters have a greater diamond content and wear height than smaller ones. However, their impact resistance is weaker. When drilling in hard formations, the formations are difficult for PDC cutters to penetrate, and the impact damage to the cutters is greater. Therefore, smaller PDC cutters are generally used in hard formations. However, smaller cutters have a smaller wear height, a lower diamond content, and a relatively shorter wear life. This presents a paradox in the selection of PDC cutters for use in hard formations.

[0004] Coring drilling is often not conducted in formations of relatively uniform lithology; instead, it is necessary to penetrate a variety of formations with varying hardness and lithology. Because PDC cutters are somewhat brittle and have relatively poor stratum adaptability, changes in strata can lead to PDC cutter damage or a reduction in drill bit penetration speed, resulting in low coring footage per single pass.

[0005] When performing coring operations, first disassemble the outer barrel and inner barrel assembly, lift out the inner barrel assembly, loosen the core gripping mechanism at the bottom of the inner barrel assembly, and move the inner barrel assembly to the ramp or the front of the drilling platform for coring operations. The coring process is time-consuming and labor-intensive. When drilling into deep, difficult-to-drill, loose, and broken formations, the core is broken and unformed. When coring, the inner barrel needs to be struck, which aggravates the breakage of the core and also brings difficulties to the later core sampling. Summary of the Invention

[0006] The present invention provides a fast-core coring drill bit, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problems of conflicting selection of PDC teeth in the existing PDC drill bit, as well as the time-consuming and labor-intensive coring, low construction efficiency and safety hazards.

[0007] The technical solution of the present invention is achieved through the following measures: a fast-coring coring drill bit, including a coring outer cylinder, the outer side of the lower end of the coring outer cylinder is connected to the drill bit body through a thread, the outer side of the lower end of the drill bit body is fixedly installed with a knife wing along the circumference, the outer side of the knife wing is fixedly installed with PDC teeth of different sizes, the inner side of the coring outer cylinder is provided with a coring inner cylinder, the outer side of the lower end of the coring inner cylinder is fixedly installed with an inner cylinder short section whose lower part is located below the coring outer cylinder, a connecting short section is fixedly installed between the outer side of the lower part of the inner cylinder short section corresponding to the position below the coring inner cylinder and the inner side of the drill bit body, the inner side of the lower part of the connecting short section is connected to a guide head through a fixing part, and a core claw is fixedly installed on the inner side of the guide head.

[0008] The following are further optimizations and / or improvements to the above technical solutions:

[0009] The PDC teeth may be arranged in such a manner that large-sized teeth and small-sized teeth are arranged alternately.

[0010] The above may also include a spring. The inner side of the upper part of the drill bit is provided with a first inner ring groove, a second inner ring groove and a third inner ring groove with successively decreasing inner diameters. The connecting short section is located in the first inner ring groove. A mounting ring groove is provided on the outer side of the lower end of the guide head corresponding to the lower side of the first inner ring groove. A spring is provided between the upper side of the mounting ring groove and the lower side of the second inner ring groove and is sleeved on the outer side of the guide head. The lower end of the guide head is located in the third inner ring groove.

[0011] The outer side of the connecting short section may be uniformly distributed along the circumference with at least sixteen semicircular flow grooves opening outward and penetrating vertically. At least six water holes penetrating vertically are provided on the drill body corresponding to the upper side of the first inner ring groove.

[0012] A positioning inner ring groove may be provided on the inner side of the lower end of the connecting short section corresponding to the position above the fixing screw, and a positioning outer ring platform may be provided on the outer side of the guide head corresponding to the position below the positioning inner ring groove, and the upper side of the positioning outer ring platform abuts against the lower side of the positioning inner ring groove.

[0013] At least two auxiliary threaded holes that penetrate inside and outside can be provided along the circumference of the inner cylinder short section corresponding to the position between the coring inner cylinder and the connecting short section.

[0014] The above may also include a sealing ring, which is provided between the guide head and the connecting joint.

[0015] The frequency converter is faster and more frequent, so the speed of the drill bit to reduce the risk of accidents, so the use of PDC cutters is very fast and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attachment Figure 1 It is a schematic diagram of the main cross-sectional structure of the best embodiment of the present invention.

[0017] Attachment Figure 2 For attachment Figure 1 Schematic diagram of the top view of the drill body.

[0018] Attachment Figure 3 For attachment Figure 1 Schematic diagram of the enlarged structure of the connecting short section.

[0019] Attachment Figure 4 For attachment Figure 3 Schematic diagram of the cross-sectional structure at AA.

[0020] The codes in the accompanying drawings are: 1 for the drill bit body, 2 for the blade, 3 for the PDC tooth, 4 for the coring outer cylinder, 5 for the coring inner cylinder, 6 for the inner cylinder short section, 7 for the connecting short section, 8 for the core claw, 9 for the fixing screw, 10 for the guide head, 11 for the spring, 12 for the first inner ring groove, 13 for the third inner ring groove, 14 for the flow groove, 15 for the water eye, 16 for the positioning outer ring platform, 17 for the auxiliary threaded hole, and 18 for the sealing ring. DETAILED DESCRIPTION

[0021] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions.

[0022] In the present invention, for the convenience of description, the relative position relationship of each component is described based on the Figure 1 For example, the positional relationships of front, back, up, down, left, and right are determined according to the layout directions of the drawings in the specification.

[0023] The present invention will be further described below in conjunction with the embodiments and accompanying drawings:

[0024] As attached Figure 1 、 2As shown in Figures 3 and 4, the fast-coring coring drill bit includes a coring outer cylinder 4, the outer side of the lower end of the coring outer cylinder 4 is connected to the drill bit body 1 through a thread, the outer side of the lower end of the drill bit body 1 is fixedly installed with a knife wing 2 along the circumference, and the outer side of the knife wing 2 is fixedly installed with PDC teeth 3 of different sizes, the inner side of the coring outer cylinder 4 is provided with a coring inner cylinder 5, the outer side of the lower end of the coring inner cylinder 5 is fixedly installed with an inner cylinder short section 6 whose lower part is located below the coring outer cylinder 4, a connecting short section 7 is fixedly installed between the outer side of the lower part of the inner cylinder short section 6 corresponding to the position below the coring inner cylinder 5 and the inner side of the drill bit body 1, the inner side of the lower part of the connecting short section 7 is connected to a guide head 10 through a fixing part, and a core claw 8 is fixedly installed on the inner side of the guide head 10.

[0025] Depending on the requirements, the fixing parts can be screws, pins, etc.

[0026] During use, the blades 2 of the drill bit body 1 use PDC teeth 3 of different sizes, which enhances the adaptability of the PDC core drill bit to the formation. When drilling in soft formations, the larger-sized PDC teeth 3 can increase the scraping and rock breaking capacity of the drill bit, ensuring the drilling speed of the drill bit in soft formations; when drilling in hard formations, the smaller-sized PDC teeth 3 maintain the invasive ability and aggressiveness of the drill bit, which can improve the rock breaking efficiency of the core drill bit in hard formations. The invention can realize the rapid coring of medium and long barrels, improve the working stability of the coring drill bit, extend the service life of the drill bit, improve the guiding ability of the drill bit, and enhance the formation adaptability of the coring drill bit, especially the drilling performance of soft and hard interlaced formations. By providing the connecting short section 7 and the guide head 10 and connecting them together by the fixing screw 9, when coring, the drill body 1 is disassembled and the fixing part is disassembled, and the guide head 10 can be disassembled, thereby avoiding the problem that the lower part of the inner barrel assembly in the original structure cannot be disassembled. After the guide head 10 is disassembled, the core is exposed, and the auxiliary coring tool can be used to take out the core without lifting the inner barrel assembly as a whole, which is simpler and faster.

[0027] The above-mentioned rapid core sampling drill bit can be further optimized and / or improved according to actual needs:

[0028] As attached Figure 1 As shown, the PDC teeth 3 are arranged in a manner that large-sized teeth and small-sized teeth are arranged alternately. When in use, such an alternating arrangement of large and small teeth can avoid the problem of tooth collapse when PDC teeth 3 of the same size are concentrated together for drilling.

[0029] As attached Figure 1As shown, it also includes a spring 11. The inner side of the upper part of the drill head is provided with a first inner ring groove 12, a second inner ring groove and a third inner ring groove 13 with successively decreasing inner diameters. The connecting nipple 7 is located in the first inner ring groove 12. A mounting ring groove is provided on the outer side of the lower end of the guide head 10 corresponding to the lower side of the first inner ring groove 12. A spring 11 is provided between the upper side of the mounting ring groove and the lower side of the second inner ring groove, which is sleeved on the outer side of the guide head 10. The lower end of the guide head 10 is located in the third inner ring groove 13. When in use, the coring inner cylinder 5 is buffered by the spring 11, and the first inner ring groove 12, the second inner ring groove and the third inner ring groove 13 are provided to limit the position, so as to assist in straightening the coring inner cylinder 5.

[0030] As attached Figure 3 、 4 As shown, at least sixteen semicircular flow grooves 14, each opening outward and extending vertically, are evenly distributed along the circumference of the connecting sub 7. At least six vertically extending water holes 15 are also provided along the circumference of the drill bit body 1, corresponding to the upper side of the first inner annular groove 12. During use, the provision of the semicircular flow grooves 14 increases the flow area, allowing rock cuttings to be discharged through the flow grooves 14 and water holes 15, reducing circulating pressure loss and core drilling pressure, thereby reducing component erosion.

[0031] As attached Figure 1 、 3 As shown in Figures 4 and 5, the lower portion of the connecting sub 7 is provided with at least two first fixing threaded holes extending inside and outside along the circumference. A second fixing threaded hole opening outward is provided on the outside of the guide head 10 corresponding to each first fixing threaded hole position. A fixing screw 9 with the inner end positioned in the second fixing threaded hole is provided in the first fixing threaded hole. A positioning inner ring groove is provided on the inner side of the lower end of the connecting sub 7 corresponding to the position above the fixing screw 9. A positioning outer ring platform 16 is provided on the outer side of the guide head 10 corresponding to the position below the positioning inner ring groove. The upper side of the positioning outer ring platform 16 abuts against the lower side of the positioning inner ring groove. During use, the provision of the positioning inner ring groove facilitates accurate positioning of the upper and lower positions of the first fixing threaded holes when installing the guide head 10 and the connecting sub 7, facilitating quick installation.

[0032] As attached Figure 1 As shown, at least two auxiliary threaded holes 17 are provided along the circumference of the inner barrel sub 6, corresponding to the position between the coring inner barrel 5 and the connecting sub 7. During use, if the core is heavy and the fixing screws 9 are difficult to remove, the screws can be inserted into the auxiliary threaded holes 17 to support the core inside, thereby reducing the weight of the lower part of the core and facilitating the removal of the fixing screws 9 for coring.

[0033] As attached Figure 1 As shown, a sealing ring 18 is also included, and a sealing ring 18 is provided between the guide head 10 and the connecting joint. When in use, if closed coring is performed, the sealing ring 18 can prevent the closed liquid from flowing out of the gap between the connecting joint and the guide head 10.

[0034] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A fast core drilling bit, characterized by It includes a coring outer cylinder, the outer side of the lower end of the coring outer cylinder is connected to the drill bit body through a thread, the outer side of the lower end of the drill bit body is fixedly installed with a knife wing along the circumference, the outer side of the knife wing is fixedly installed with PDC teeth of different sizes, the inner side of the coring outer cylinder is provided with a coring inner cylinder, the outer side of the lower end of the coring inner cylinder is fixedly installed with an inner cylinder short section with the lower part located below the coring outer cylinder, a connecting short section is fixedly installed between the outer side of the lower part of the inner cylinder short section corresponding to the position below the coring inner cylinder and the inner side of the drill bit body, the inner side of the lower part of the connecting short section is connected to a guide head through a fixing piece, and a core claw is fixedly installed on the inner side of the guide head; The PDC teeth are arranged in such a way that large-sized teeth are alternately arranged with small-sized teeth; The drill bit also includes a spring, wherein the inner side of the upper portion of the drill bit is provided with a first inner ring groove, a second inner ring groove, and a third inner ring groove, the inner diameters of which decrease in sequence, the connecting nipple is located in the first inner ring groove, and a mounting ring groove is provided on the outer side of the lower end of the guide head corresponding to the lower side of the first inner ring groove, a spring is provided between the upper side of the mounting ring groove and the lower side of the second inner ring groove and is sleeved on the outer side of the guide head, and the lower end of the guide head is located in the third inner ring groove; At least sixteen semicircular flow grooves opening outward and penetrating vertically are evenly distributed along the circumference of the outer side of the connecting short section, and at least six water holes penetrating vertically are provided on the drill body corresponding to the upper side of the first inner ring groove.

2. The rapid core drilling bit according to claim 1, characterized in that At least two first fixing threaded holes are provided along the circumference of the lower part of the connecting short section, and a second fixing threaded hole opening outward is provided on the outside of the guide head corresponding to the position of each first fixing threaded hole. A fixing screw with the inner end located in the second fixing threaded hole is provided in the first fixing threaded hole. A positioning inner ring groove is provided on the inner side of the lower end of the connecting short section corresponding to the position above the fixing screw, and a positioning outer ring platform is provided on the outside of the guide head corresponding to the position below the positioning inner ring groove, and the upper side of the positioning outer ring platform is abutted against the lower side of the positioning inner ring groove.

3. The rapid core drilling bit according to claim 1 or 2, characterized in that At least two auxiliary threaded holes that penetrate inside and outside are arranged along the circumference of the inner cylinder short section corresponding to the position between the core inner cylinder and the connecting short section.

4. The rapid core drilling drill bit according to claim 1 or 2, characterized in that It also includes a sealing ring, which is provided between the guide head and the connecting joint.

5. The rapid core drilling drill bit according to claim 3, characterized in that It also includes a sealing ring, which is provided between the guide head and the connecting joint.

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