MXPA97002740A

MXPA97002740A - Perforation trepano with hiperdu cutting elements

Info

Publication number: MXPA97002740A
Application number: MXPA/A/1997/002740A
Authority: MX
Inventors: E Scott Danny; Co Pessier Rudolf; J Farr Robert; R Jurewicz Stephen; M Jensen Kenneth; D Jones Paul
Original assignee: Baker Hughes Incorporated
Priority date: 1996-04-17
Filing date: 1997-04-15
Publication date: 1998-10-30

Abstract

The present invention relates to a drilling bit having a trephine body and at least one supporting cantilever dependent in and down the body of the trepan. A cutter head is mounted for rotation on the support shaft and includes a plurality of cutting elements. At least one of the cutting elements has a generally cylinder body formed of hard metal with a convex cutting end. A plurality of spaces between parallel grooves, substantially linear, are formed on the cutting end of the body. The spaces between grooves have arcuate upper surfaces and define grooves between the space between grooves having arcuate lower surfaces. A layer of hyperhard material is formed on the cutting end of the body and is brought into contact with the spaces between grooves and the grooves formed on it.

Description

PERFORATION TREPANO WITH CUTTING ELEMENTS HI PERDUROS BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an improvement in the cutting structure of drilling trephines of the rolling cutter variety. More specifically, the present invention relates to the treadmills with rolling cutter head having improved diamond or hyperhard cutting elements.

Prior art information: The success of rotary drilling allowed the discovery of deep oil and gas deposits. The rotary trepan was an important invention that made rotary drilling economical. Only the soft earth formations could be commercially penetrated with the prior art sheet trephine or trephine trephine, but the two-cone trephine invented by Howard R. Hughes, US Patent No. 930,759, pierced the cover rock in the Spindletop field near Beaumont, Texas, with relative ease. That venerable invention, within the first decade of this century, could pierce a small fraction of the depth and speed of the modern rotary trepan. If the original Hughes trephine drilled for hours, the modern trephine drills for days. Modern trephines sometimes pierce through thousands of REF: 24541 meters instead of only a few meters. Many advances have contributed to the impressive improvement of the rotary trephines. In the drilling of sounding wells in earth formations by the rotating method, the trephines equipped with one, two, or three rolling cutter heads are employed. The trephine is secured to the lower end of a drill string or column that is rotated from the surface or by motors or turbines at the bottom of the bore. The cutter heads mounted on the trephine roll and slide on the bottom of the borehole as the drill string or column is rotated, to contact and disintegrate thereby the material of the formation to be removed. The rolling cutter heads are provided with teeth or cutting elements that are forced to penetrate and empty the bottom of the borehole by the weight of the linkage or the drill string. The bottom cutting elements and the sidewalls of the borehole are removed by flushing through the drilling fluid that is pumped down from the surface through the roving or hollow rotary column and are transported in suspension in the fluid of drilling to the surface. It has been a conventional practice for many years to provide diamond or hyperhard cutting elements, or inserts in drilling bits known as PDC, or trephines with fixed cutting elements. The excellent characteristics of hardness, wear and heat dissipation of diamond and other hyperhard materials are of particular benefit in the trepan blades or fixed cutting head, in which the main cutting mechanism is by scraping. The diamond cutting elements in the fixed cutting element or the driving trephines commonly comprise a natural or polycrystalline diamond disc or board formed integrally on a cemented tungsten carbide or similar hard metal substrate in the form of a rod or cylindrical body that is subsequently welds or mechanically adjusts on the trephine body. One difficulty encountered with such arrangements is that the diamond table can be separated from its substrate, when the interface between the diamond and the substrate is loaded in shear stress * or tension. One solution to the problem of shear breaking has been to contour the inner surface with spaces between raised ribs, where an interface is formed between the substrate and the diamond layer that is resistant to shear and tensile stresses. Examples of this are found in the North American patent No. 4, 109,737, issued to Bovenkerk, U.S. Patent No. 5,120,327 issued to Dennis, U.S. Patent No. 5,351,772 issued to Smith, and U.S. Patent No. 5,355,969 issued to Hardy et al. The implementation of diamond cutting elements as the main cutting structure in the drilling trephines of the rolling cutting head variety has been somewhat less successful than with the drilling bits of the fixed cutting head variety. One reason for this lack of success is that the primary cutting elements of trepan with rolling cutter head are subjected to more complex loads, depending on their location on the cutting heads, which makes the separation of the diamond tables from their substrates most likely. In addition, because the loads found by the cutting elements of the trepan with rolling cutter head are commonly much larger in magnitude than the loads sustained by the cutting elements of the trepan with fixed head, stress concentrations caused by the space arrangements between ribs and notch of the prior art at the interface between the diamond and its substrate, as shown by U.S. Patent No. 5,379,854, issued to Dennis, can cause the diamond to crack or fracture. A solution is found in the US patents Nos. 4,525,178; 4,504,106 and 4,694,918 issued to Hall, which disclose cutting elements for a trepan with a rolling cutter head having the diamond and substrate formed integrally with a transition layer of a diamond and carbide composite, between the diamond layer and the carbide layer . This transition layer is proposed to reduce the residual stresses between diamond and carbide, because the composite material reduces differences in mechanical and thermal properties between diamond and carbide materials. Another solution written in commonly assigned US Patent No. 5,119,714 issued to Scott is to form a hard metal sleeve around a diamond center. Unfortunately, this may be more difficult to manufacture than conventional flat PDC parts, and is subject to costly and complex finishing operations. Therefore, there is a need for diamond cutting elements or inserts for drilling bits of the variety of rolling cutter head that are sufficiently durable to withstand the severe environment at the bottom of the hole and that are economical to manufacture.

* - BRIEF DESCRIPTION OF THE INVENTION It is a general object of the present invention to provide a drilling bit for the variety of rolling cutter head, which has improved hyperhard hard cutting elements. This and other objects of the invention are obtained by providing a drilling bit having a trephine body and at least one cantilever supporting shaft or shaft dependent inwardly and downwardly from the trephine body. A cutting head is mounted for rotation on the support shaft and includes a plurality of cutting elements. At least one of the cutting elements has a generally cylindrical body formed of hard metal with a convex cutting end. A plurality of spaces between substantially linear parallel grooves are formed on the convex cutting end of the body. The spaces between grooves have flat upper surfaces and define grooves between spaces between grooves having arcuate lower surfaces. A layer of the hyperhard material is formed on the cutting end of the body and is brought into contact with the spaces between grooves and the grooves formed thereon. According to the preferred embodiment of the present invention, the cutting end is chisel-shaped and defines a pair of flanks that converge to define a ridge. A pair of ends join the flanks. The spaces and grooves are formed on the flanks substantially parallel to the ridge and the layer of the hyperhard material covers the flanks, the ridge and the ends of the cutting end. Spaces and grooves can also be provided over the ends. According to the preferred embodiment of the present invention, the hard metal is cemented tungsten carbide and the hyperhard material is polycrystalline diamond.

DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a drilling bit of the variety of rolling cutter head according to the present invention. Figure 2 is an elevation view of the improved cutting element according to the present invention.

Figures 3A-3C are views in front elevation, in plan, and in lateral elevation respectively of the body of the cutting element of Figure 2. Figure 4 is an enlarged view of a portion of the cutting element body of Figures 3A-3C . Figure 5 is an elevation view, similar to Figure 3A of an alternative embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference now to the figures and in particular to Figure 1, a drilling bit 11 according to the present invention is illustrated. The trepan 11 includes a trephine body 13, which is threaded in its upper extension 15 for connection to a drill string or column. Each leg or section of the trepan 11 is provided with a lubricant compensator 17. At least one nozzle 19 is provided in the trephine body 13 for spraying drilling fluid from within the drill string or column to cool and lubricate the trepan 11 during the drilling operation. Three cutter heads 21, 23, 25 are rotatably secured to a support shaft associated with each leg of the body 13 of the trephine. Each cutter head 21, 23, 25 has a cutting cover surface including a contact surface 31, and a back surface 41. A plurality of cutting elements are arranged in generally circumferential rows on the surface of the cover of the cutter head. The cutting elements are preferably secured in holes in the cutting heads by interference fit and include contact cutting elements 33 on the contact surface 31, rear cutting elements 43 on the rear surfaces 41 and several internal rows of cutting elements. Cutting elements or scrapers 51 are generally provided at the intersection of the contact surfaces 31 and rear 41 as described in commonly assigned US Pat. Nos. 5 and 5., 351, 768 and 5,479,997 issued to Scott et al. Figure 2 is an elevation view of a cutting element 51 according to the present invention. Although the illustrated cutting element corresponds to a cutting insert or scraper (51 in FIG. 1), the present invention also pertains to rear inserts (43 in FIG. 1) and inner row elements. The cutting element 51 comprises a generally cylindrical body 53 formed of hard metal, preferably cemented tungsten carbide. A convex chisel cutting end of the body 53 has a pair of flanks 55 that converge at about 45 ° to define a ridge 57. A pair of ends 59 join flanks 55 and ridge 57 to cylindrical body 53. The cutting end of the element 51 is formed of a layer of hyperhard material applied on the flanks 55, the ridge 57 and the ends 59. of the body 53. The hyperhard materials include natural diamond, polycrystalline diamond, cubic boron nitride and others. Similar materials approaching the diamond in hardness and having hardness up to approximately 3500 to 5000 on the Knoop hardness scale. Figures 3A-3C are views in front elevation, in plan and in lateral elevation respectively of the cylindrical body 53 before the formation of the layer of the hyperhard material on the cutting end. For ease of reference, the same reference numerals are used as used in Figure 2, although the hyperhard material is not formed on the cutting end of the body 53. The cutting end of the body 53, comprising the flanks 55, the ridges 57 and the ends 59, is of a main diameter smaller than the body 53 and defines a threaded flange to allow the application of the cap of the hyperhard material, to result in an element that is continuous and level in transition from the hyperhard material from the cutting end to the hard metal of the cylindrical portion of the body 53. The flanks 55 of the cutting end are provided with a plurality of substantially linear parallel grooves (61 in FIG. 4) to define grooves (63 in FIG. 4) between the spaces between grooves. After the layer of the hyperhard material is formed on the flanks 55, the crests 57 and the ends 59 of the cutting end of the body 53, the hyperhard material is brought into contact with the spaces between grooves 61 and the grooves 63 to provide an interphase interface. interfixing between the hard metal and the hyperhard material that is resistant to the shear stress and the tensile forces acting between the hyperhard metal and the hard metal.

Figure 4 is an enlarged view of a portion of a flank (55 in Figures 3A-3C) of the cutting end of the body 53. The spaces 61 between grooves have flat or rectilinear upper surfaces and the grooves 63 have arcuate bottom surfaces. To avoid stress concentrations at the interface, the intersections of the groove spaces 61, and the grooves 63 define oblique angles instead of right or acute angles. The bottoms or bottoms of the grooves 63 have generally circular radii. The upper and lower surfaces of the spaces 61 between grooves and the grooves 63 are thus free of sharp corners and the like, to reduce the concentrations of stress at the interface between the hyperhard material (shown in broken lines) and the hard metal body. , to reduce by this the probability of crack or fracture of the hyperhard material. As shown in Figure 4, the spaces between grooves are preferably 0.020 cm (0.008 inches) wide and spaced 0.0899 cm (0.035 inches) apart from center to center. The grooves 63 are 0.01778 cm (0.007 inches) deep and have a radius of 0.03048 cm (0.012 inches). The included angle between the intersections of the space 61 between adjacent grooves with each groove 63 is preferably 90 °, which allows the spaces 61 between grooves and the grooves 63 to be integrally formed to the cutting end of the body 53 by processing techniques. conventional powder metallurgy, to eliminate the need for machining or rectification operations. The auxiliary furthermore in the integral formation of the grooves 63 that the ascending portions (which curve upwards towards the ridge 57) of each groove are provided with an angle of 15 ° from the vertical (all dimensions given are nominal). Figure 5 is an elevation view, similar to Figure 3A, of an alternative embodiment of the present invention, in which the spaces and grooves are formed at ends 59, also as on the flanks 55 of the cutting end of the body 53. As with the spaces 61 between grooves and the grooves 63 in Figure 4, the spaces between grooves and grooves are substantially linear (although curved along the contour of the ends 59) and parallel to the ridge 57 and are formed to avoid concentrations of stress in the layer of the hyperhard material. The hard metal body 53 of the cutting element 51 is formed by using conventional powder metallurgy techniques, including hot isostatic pressing (HIP). The polycrystalline diamond super hard layer is formed by using high temperature, high pressure processes, such as those described in U.S. Patent Nos. 3,745,623 and 3,913,280. The drilling bit in accordance with the present invention has a number of advantages. A major advantage is that the trephine is provided with hyperhard hard cutting elements that can withstand the rigors of drilling with tread cutter heads and still be manufactured economically. The invention has been described with reference to a preferred embodiment thereof. It is not thus limited but is susceptible to variation and modification without deviating from the scope and spirit of the invention. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects referred to therein.

Having described the invention as above, property is claimed as contained in the following

Claims

Claims 1. A drilling bit, characterized in that it comprises: a body of the trephine; at least one supporting cantilevered shaft inwardly and downwardly of the trephine body; a cutter head mounted for rotation on the support shaft, which includes a plurality of cutting elements; at least one of the cutting elements has: a generally cylindrical body of hard metal, the body has a convex cutting end; a plurality of spaces between parallel grooves, substantially linear, formed on the cutting end of the body, the spaces between grooves have flat upper surfaces and define grooves between the spaces between grooves having arcuate lower surfaces, the intersections of the spaces and the grooves define oblique angles; and a layer of hyperhard material formed on the cutting end of the body and which comes into contact with the spaces and grooves formed thereon.
2. The drilling bit according to claim 1, characterized in that the cutting end is of chisel configuration and defines a pair of flanks that converge to define a ridge and a pair of ends that join the flanks, the spaces are formed on the flanks substantially parallel to the ridge and the layer of the hyperhard material covers the flanks, the crest and the ends of the cutting end.
3. The drilling bit according to claim 1, characterized in that the hard metal is cemented tungsten carbide and the hyperhard material consists of polycrystalline diamond.
4. The drilling bit according to claim 1, characterized in that the spaces between grooves and grooves are formed integrally with the body of the hard metal.
5. A drilling bit, characterized in that it comprises: a trephine body; at least one supporting cantilevered shaft inwardly and downwardly of the trephine body; a cutter head mounted for rotation on the support shaft, the cutter head includes a plurality of cutting elements; at least one of the cutting elements has: a generally cylindrical body of hard metal, the body having a convex cutting end with a main dimension smaller than the diameter of the body member; a plurality of spaces between parallel grooves, substantially linear, formed on the cutting end of the body element, the spaces between grooves have flat upper surfaces and define grooves between the spaces and have arcuate lower surfaces, the intersections of the grooves and the spaces define oblique angles; and a layer of hyperhard material formed on the cutting end of the cutting element of the body member and contacting the spaces and grooves formed thereon and extending to the level with the diameter of the body member.
6. The drilling bit according to claim 5, characterized in that the cutting end is chisel-shaped and defines a pair of flanks that converge to define a ridge and a pair of ends that join the flanks, the spaces between grooves are formed on the flanks substantially parallel to the ridge and the layer of the hyperhard material covers the flanks, the ridge and the ends of the cutting end.
7. The drilling bit according to claim 6, characterized in that the hard metal consists of cemented tungsten carbide and the hyperhard material consists of polycrystalline diamond.
8. The drilling bit according to claim 5, characterized in that the spaces between grooves and grooves are formed integrally with the body of the hard metal.
9. A drilling bit, characterized in that it comprises: a body of the trephine; at least one supporting cantilevered shaft inwardly and downwardly of the trephine body; a cutter head mounted for rotation on the support shaft, the cutter head includes a plurality of cutting elements; at least one of the cutting elements has: a generally cylindrical body of hard metal, the body has a cutting edge in the form of a chisel that has a pair of flanks that converge to define a ridge and a pair of ends that join the flanks , the cutting end has a main dimension smaller than the diameter of the body, which defines a flange at the intersection of the cutting end and the body member; a plurality of parallel, substantially linear groove spaces formed on the flanks substantially parallel to the ridge, the spaces between grooves, have flat upper surfaces and define grooves between the spaces between grooves having arcuate lower surfaces, the intersections of the grooves and the spaces define oblique angles; and a layer of hyperhard material formed on the ridge, the flanks and the ends that come into contact with the spaces and the grooves formed on the flanks, the layer of the hyperhard material is flush with the rim.
10. The drilling bit according to claim 9, characterized in that the spaces between grooves and grooves are formed integrally with the hard metal body.
11. The drilling bit according to claim 9, characterized in that the hard metal consists of cemented tungsten carbide and the hyperhard material consists of polycrystalline diamond.
12. The drilling bit according to claim 9, characterized in that the ends are provided with spaces between grooves defining grooves, spaces and grooves have surfaces upper and lower arched.