MXPA01000483A - Rotary cone drill bit with machined cutting structure and method - Google Patents

Abstract

A rotary cone drill bit is provided with at least one cutter cone assembly having a machined cutting structure which will maintain an effective cutting profile despite abrasion, erosion and/or wear of the associated cutting elements. The machined cutting structure may be formed on a generally cone shaped blank by a series of lathe turns and/or plunge cuts. The cutting elements may be formed with an aggressive cutting profile. For one application, the crest of each cutting element has the general configuration of an ogee curve. A layer of hardfacing material may be applied over all or selected portions of the machined cutting structure.

Description

ROTATING CONE DRILL WITH MACHINED CUTTING STRUCTURE AND METHOD TECHNICAL FIELD OF THE INVENTION This invention relates generally to rotary cone drills and, more particularly, to a rotating cone drill having at least one cutter cone assembly with a machined cutting structure and to a method for forming the cutter structure.

BACKGROUND OF THE INVENTION A wide variety of rotary cone bits are used to drill deep holes for oil and gas exploration and production and for mining operations.

Such drill bits usually employ multiple rolling cutter cone assemblies, also known as rotary cutter assemblies. Cutter cone assemblies are typically mounted on the respective drills or dies extending downwardly and inwardly relative to an axis extending through an associated drill body so that the conical surfaces of the cutter cone assemblies tend to to rotate at the bottom of a hole in contact with the adjacent ground formation. Cutter cone assemblies generally have circumferential rows of milled teeth or inserts for scraping, cutting and / or chiseling the formation at the bottom of the deep bore. The formation of teeth in a conical shaped floor generally through milling is usually a relatively expensive and time-consuming process. Multiple milling steps are often required to form each tooth of a typical milled tooth cutting structure.

The teeth milled in conventional cone assemblies tend to wear out in those areas that engage with the side and bottom wall of a deep hole during drilling operations. The milled teeth typically have a general pyramidal configuration with a trapezoidal cross section extending from the outer surface of the associated cutter cone assembly. The generally pyramidal configuration is formed during the milling operation to provide sufficient structural support with the adjacent portions of the associated cutter cone assembly. As a result of the inclined surfaces associated with the pyramidal, the milled teeth may generally become blunt due to abrasion, erosion and wear during drilling operations. Unless an additional weight is applied to the associated rotating conical drill, the penetration rate may generally decrease while the contact area increases with the depth of a deep bore resulting from wear of the milled teeth having a generally pyramidal The service life of a rotating cone drill having cutter cone assemblies with respective milling cutter structures can be improved by the addition of wear and abrasion resistant materials to the selected wear areas of each tooth. The addition of wear and abrasion resistant materials to milled teeth is sometimes referred to as "hard coating". In a hard coating operation, the wear and abrasion resistant material is applied to the teeth to provide not only a wear resistant surface to reduce the rate at which each milled tooth is worn, but also to maintain the Cutting edges sharper while teeth are worn.

Examples of rotating cone drills having cutter cone assemblies with milled tooth cutter structures are shown in U.S. Patent No. 5,579,856 entitled Cut Length Length and Method for Milling Tooth Slicer Structure. and U.S. Patent No. 2,533,256 entitled Broca Cutter. Such drill bits can sometimes be referred to as "steel tooth" bits or "milled tooth" bits.

Conventional cutter cone assemblies with milled teeth often include multiple rows of teeth disposed on the respective conical surfaces. Such cutter cone assemblies somehow look like cylindrical gears or bevel gears with internal gear teeth or interlock teeth. Variations of these patterns include skewing of the teeth similar to that of a spiral bevel gear, or even an alternating skew to produce a fishbone effect. Another accepted version of a drill is that of an interrupted circumferential disk having an appearance that results from teeth aligned end-to-end around the periphery of the associated cutter cone assembly.

SYNTHESIS OF THE INVENTION In accordance with the teachings of the present invention, the disadvantages and problems associated with prior rotating cone drills having multiple cutter cone assemblies with milled tooth cutter structures have been substantially reduced or eliminated. One aspect of the present invention includes providing a rotating cone bit having at least one cutter cone assembly with a machined cutting structure formed by a series of machined turns and / or slanted cuts. The desired machined cutting structure can be entirely formed in a foundry or slab having a generally conical configuration associated with the cutter cone assemblies.

For one application, the machined cutting structure can be described as a series of corrugated wovens having a generally sinusoidal configuration. Each corrugated fabric preferably extends circumferentially around the conical surface of an associated cutter cone assembly. The corrugated fabrics in each cutter cone assembly are spaced apart by a distance selected from each other to provide an internal gear or superimposed relationship with the corresponding corrugated fabrics found in the adjacent cutter cone assemblies. Depending on the anticipated downhole drilling conditions, the machined cutting structure can be treated, heated or covered with a layer of hard coating material using the techniques available at the time and the materials or any future techniques and materials developed for rotating cone drills For another application, the machined cutting structure can be described as a series of interrupted fabrics formed by cutting or machining a continuous corrugated knitting generally into individual cutter elements extending from the outer surface of an associated cutter cone assembly. The fabrics interrupted in each cutter cone assembly and the respective individual cutter elements of each interrupted fabric are preferably separated by a distance selected from one another to provide an overlapped or internal gear ratio with corresponding interrupted fabrics and the cutter elements formed in each other. the adjacent cutter cone assemblies. The present invention allows the optimization of the resulting machined cutting structure to provide a substantially increased borehole drilling action.

The technical advantages of the present invention include the ability to use a wide variety of operations, metal forming and / or machining to form a cutting structure on the outside of a cutter cone assembly with aggressive cutter profiles. As the cutter cone assemblies with selected machined cutter structures are rolled over the bottom of a bore, each cutter element may preferably first attack the formation of a deep bore with a sliced-type effect, and then result in a bore-type effect. Plowing and cross cutting. This combination of drilling actions may increase the penetration rate, as well as cleaning the bottom of the improved hole. Machined cutting structures can be formed on the cutter cone assemblies in accordance with the teachings of the present invention to provide a more favorable drill geometry to improve directional drilling control. The resulting machined cutting structures provide a circumferential surface contact with the bottom formation of a bore which improves dynamic stability and reduces wear without any reduction in deep hole drilling efficiency.

Many different machined turn steps may be used, inclined cutting steps and / or other machined metal techniques may be used in accordance with the teachings of the present invention to form machined cutting structures with a wide variety of geometric configurations and of cutter profiles selected for each cutter element. The present invention is not limited to any specific sequence of machined operations, the profiles of the cutter, the corrugated fabric configuration and / or the interrupted fabric configurations. The present invention also allows the use of a wide variety of metals, metal alloys and other materials to form each cutter cone assembly.

In addition, the technical advantages of the present invention include providing a rotary cone drill with at least two and preferably three cutter cone assemblies having machined cutting structures. The geometric configuration and the cutter profile of each cutter element can be optimized to improve the total drill bit drilling efficiency of the associated bit. Each cutting element is preferably formed with a generally uniform thickness and the steep sides which generally extend perpendicularly from the outer surface of an associated cutting assembly. The cutter profile of each cutter element may remain relatively sharp despite the abrasion and substantial wear of the associated cutter. An aggressive cutter profile can be formed on each cutter element to allow increasing the penetration rate of the associated bit, while at the same time extending the auger service life downwards since the cutter elements will remain relatively sharp despite of abrasion and wear. Cutter cone assemblies having machined cutting structures formed in accordance with the teachings of the present invention may be used with rotating cone drills, core drills, apertures, and other types of ground drilling equipment.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numbers indicate similar characteristics, and wherein: Figure 1 is a schematic drawing in elevation and in section with parts broken away from a rotary cone drill, incorporating the teachings of the present invention, coupled to one end of a drill string placed in a deep hole; Figure 2 is a schematic drawing showing an isometric view of the rotating cone drill of Figure 1; Figure 3 is an end view of a rotating cone drill of Figure 2; Figure 4A is a schematic drawing showing an isometric view of an intermediate step while forming a cutter cone assembly with a first cutter structure machined from a generally cone shaped section in accordance with the teachings of the present invention; Figure 4B is a schematic drawing showing an isometric view of the cutter cone assembly of Figure 4A during another intermediate step while forming the first cutting structure machined in accordance with the teachings of the present invention; Figure 4C is a schematic drawing showing an isometric view of the cutter cone assembly of Figure 4A having the first machined cutting structure formed therein in accordance with the teachings of the present invention; Figure 5A is a schematic drawing showing an isometric view of an intermediate step while forming a cutter cone assembly with a second cutter structure machined from a generally cone-shaped section in accordance with the teachings of the present invention; Figure 5B is a schematic drawing showing an isometric view of the cutter cone assembly of the figure 5A during another intermediate step while forming the second cutting structure machined in accordance with the teachings of the present invention; Figure 5C is a schematic drawing showing an isometric view of the cutter cone assembly of Figure 5A having the second machined cutting structure formed therein in accordance with the teachings of the present invention; Figure 6A is a schematic drawing showing an isometric view of an intermediate step while forming a cutter cone assembly with a third cutter structure machined from a generally cone-shaped section in accordance with the teachings of the present invention; Fig. 6B is a schematic drawing showing an isometric view of the cutter cone assembly of Fig. 6A during another intermediate step while forming the third cutter structure machined in accordance with the teachings of the present invention; Fig. 6C is a schematic drawing showing an isometric view of the cutter cone assembly of Fig. 6A having the third machined cutting structure formed therein in accordance with the teachings of the present invention; Figure 7 is a schematic drawing showing an isometric elongated view of a cutter member associated with the rotating cone drill of Figure 3.

DETAILED DESCRIPTION OF THE INVENTION The embodiments of the present invention and their advantages are better understood by referring to Figures 1 to 7 of the drawings, the like numbers being used for corresponding and similar parts of the various drawings.

For purposes of illustration, the present invention is shown incorporated in the rotary cone bit 20 of the type used to drill a deep hole in the ground. The rotating cone bit 20 can sometimes be referred to as a "rotating bit" or "oscillating bit". The rotating cone bit 20 preferably includes a threaded connection or bolt 44 for use in coupling the drill 20 with the drill string 22. The threaded connection 44 and the corresponding threaded connection (not expressly shown) associated with the drill string 22 they are designed to allow the turning of the bit 20 in response to the turning of the drill string 22 on the surface of the well.

In figure 1, the bit 20 is shown coupled to the drill string 22 and arranged in a deep hole 24. The ring 26 is formed between the outside of the drill string 22 and the inside or the wall 28 of the deep hole 24. In addition to the rotary drill 20, the drill string 22 is usually used as a conduit for communicating communication fluids and other fluids from the well surface to the drill 20 at the bottom of the deep drill 24. Such drilling fluids they can be directed to flow from the drill string 22 to the nozzles 60 provided in the drill 20. The cutters formed by the drill 20 and any other detritus at the bottom of the deep bore 24 may be mixed with the drilling fluids that exit from the nozzles 60 and return to the surface of the well through the ring 26.

For the perforating or cutting action of the rotary cone bit 20 to occur when rolling the cutter cone assemblies 100a, 100b and 100c are rolled around the bottom of the deep hole 24 by rotating the hole-in-length string 22. Cutter cone assemblies 100a, 100b and 100c have substantially the same general configuration and the same overall dimensions except for the cutter structures 110, 120 and 130 respectively formed on the outer surfaces of the cutter cone assemblies 100a, 100b and 100c in accordance with the teachings of the present invention. The cutter cone assemblies 100a, 100b and 100c can sometimes be referred to as "rotating cone cutters" or "roller cone cutters". The internal diameter of the deep hole 24 defined by the wall 28 corresponds approximately to the combined outer diameter or the diameter of the cutting length of the cutter cone assemblies 100a, 100b and 100c. See figure 3.

The machined cutting structures 110, 120 and 130 scrape, cut, empty, slice, plow and / or chisel the sides and bottom of the deep hole 24 in response to the weight and turning applied to the bit 20 from the drill string. The machined cutting structures 110, 120, and 130 may be varied in accordance with the teachings of the present invention to provide the desired type of deep-hole drilling action appropriate for anticipated downhole formation.

The drill bit 20 shown in Figs. 1, 2 and 3 comprises a unitary or one-piece drill body 40 with the upper part 42 having a bolt or threaded connection 4 adapted thereto for securing the drill 20 to the lower end of the drill. bore string 22. Three support arms 70 are preferably coupled and extend longitudinally from the body of the opposite bore 40 of the bolt 44. Each support arm 70 preferably includes a drill bit (not expressly shown) connected to and extends from a interior surface (not expressly shown) of the respective support arm 70. Examples of such drill bits and their associated auger body, support arms and cutter cone assemblies are shown in the United States patent. America No. 5,439,067 entitled Oscillating Drill With Enchanted Fluid Area and United States of America Patent No. 5,439,068 entitled Modular Rotary Drill.

The patent of the United States of America No. 4,056,153 entitled Rotating Oscillating Drill With Multiple Row Coverage For Very Hard Formations and U.S. Patent No. 4,280,571 entitled Oscillating Drill, shows other examples of conventional rotary cone drills with cutter cone assemblies mounted on a drill bit that is project from a support arm. These patents provide additional information concerning the manufacture and assembly of auger bodies, the support arms and the cutter cone assemblies which are satisfactory for use with the present invention. A cutter cone assembly having a machined cutter structure formed in accordance with the teachings of the present invention can be used on a wide variety of drill bits and other downhole tools. The present invention is not limited to use with the drill 20 or the cutter cone assemblies 100a, 100b, and 100c.

Figure 3 shows a planar view of the bottom of the drill 20. The arrow 80 indicates the preferred direction for the twist of the drill 20. Each set of cutter cone 100a, 100b, and 100c includes the part of the respective base 102 having a generally circular flat configuration with a nose 106 disposed opposite it. The part of the base 102 preferably includes an opening (not expressly shown) and a cavity (not expressly shown) extending therefrom to allow mounting of the cutter cone assemblies 100a, 100b and 100c in the respective drills (not expressly shown). The generally tapered conical surface 104 extends from each base part 102 and terminates in the respective nose 106.

The machined cutting structures 110, 120, and 130 are formed on the outer surfaces or on the tapered, generally tapered surface 104 of the respective cutter cone assemblies 100a, 100b and 100c. The first machined cutting structure 110 includes three rows 111, 112 and 113 of cutter elements designated respectively 146, 148 and 150. The row 111 is formed immediately adjacent to the base part 102 and extends circumferentially around the conical surface 104. row 113 is formed adjacent nose 106. A row 112 extends circumferentially around conical surface 104 spaced apart from first row 111 and third row 113. See Figure 4C.

The second machined cutting structure 120 includes two rows 121 and 122 of cutter elements designated respectively at 152 and 154. The row 121 is formed immediately on one side of the associated base part 102 and extends circumferentially around the conical surface 104. The second row 122 extends circumferentially around conical surface 104 spaced apart from first row 121 and nose 106. See Figure 5C.

The third machined cutting structure 130 includes two rows 131 and 132 of cutter elements designated 156 and 158. The row 131 is formed immediately on one side of the associated base part 102 and extends circumferentially around the conical surface 104. The second row 132 of the cutter elements extends circumferentially around the tapered surface 104 separated from the first row 131 and the associated nose 106. See Figure 6C.

One of the benefits of the present invention includes the ability to select the location and configuration of each row of cutter elements and the size, configuration and orientation of each cutter element in each row to optimize drill bit performance towards below from the associated rotating cone drill. For example, the locations and configurations of the first row 111, the second row 112 and the third row 113 formed on the outside of the cutter cone assembly 100a are selected to be interlaced and / or overlapped with the first row 121, the second row 122 and third row 123 of the cutter elements formed on the outside of the cutter cone assembly 100b. In a similar manner the first row 131, the second row 132 and the third row 133 formed on the outside of the cutter cone assembly 100c are selected to overlap and interlock with the first machined cutting structure 110 and the second machined cutting structure 120.

The size, configuration and orientation of the cutting elements 146, in the first row 111 of the first machined cutting structure 110, of the cutting elements 152 in the first row 121 of the second machined cutting structure 120 and of the cutting elements 156 in the first row 131 of the third machined cutting structure 130 are preferably selected to provide an overlapped contact with the bottom of the deep bore 24 during the turning of the drill 20. The extension of the respective length of the cutter elements 146, 152 and 156 measured from the base part 102 is preferably variable. As a result of the variation or staggering of the longitudinal length of the cutting elements 146, 152 and 156, the contact area between the respective first rows 111, 121 and 131 with the bottom of the deep perforation 24 may also vary. The circumferential spacing between the respective elements 146, 152 and 156 is also varied to further provide for the contact superimposed with the bottom of the deep hole 24. As a result of the formation of the first rows 111, 121 and 131 in accordance with the teachings of the present invention the area of the total surface to make contact with the bottom of the hole 24 is increased which increases the dynamic stability of the associated rotary cone bit 20. Also, the area of increased contact between the cutting elements of the first rows 111, 121 and 131 also results in reduced wear of the associated cutter elements. As will be discussed later in more detail, these benefits are obtained without reducing the downhole drilling action associated with the machined cutting structures 110, 120 and 130.

The respective second rows 112, 122 and 132 of the cutter structures 110, 120 and 130 are formed at slightly different longitudinal distances from the respective noses 106 of the cutter cone assemblies 100a, 100b and 100c. By varying the longitudinal distance from the respective nose 106, the first cutting structure 110 includes the first groove 116 formed between the first row 111 and the second row 112. The first machined cutting structure 110 also includes a second groove 118 formed between the second row 112 and third row 113. Second machined cutting structure 120 includes a corresponding first notch 126 formed between first row 121 and second row 122. Third machined cutting structure 130 includes first nozzle 136 formed between the first row 131 and the second row 132. Selecting the desired dimensions, the configuration and orientation of the associated cutting elements 148 and the distance from the respective nose 106, the second row 112 of the first cutting structure 110 may be received within the corresponding first notch 126 of the second machined cutting structure 120 and the first notch 136 of the third machined cutting structure 130. Proper selection of the distance from the nose 106 allows the cutting elements 146, 148, 150, 152, 154, 156 and 158 to be placed between the corresponding rows of the sets of cutting cone 100a, 1,00b and 100c.

The cone-shaped section 90 shown by dotted lines in Figures 4A, 5A and 6A preferably has a general configuration and satisfactory exterior dimensions for forming the cutter cone assemblies 100a, 100b and 100c in accordance with the teachings of the present invention. The section 90 may be formed of various types of steel alloys and / or other metal alloys associated with the rotating cone drills. The section 90 can be formed of such materials using the forging and / or casting techniques as desired.

Figures 4A, 4B and 4C show several steps associated with the machined section 90 in accordance with the teachings of the present invention for manufacturing the machined cutting structure 110 on the outer surface 104 of the cutter cone assembly 100a. For the embodiment shown in Figure 4A, the section 90 is preferably placed in a lathe or in a similar metal working machine. A plurality of machined turns or lathe cuts can then be used to form the base part 102 and the nose 106 in the section 90. The turns of the lathe or the lathe cuts can also be used to form the tapered conical surface 104. with the first concentric ring or plane 127, the second concentric ring or plane 128 and the third concentric ring or plane 129 extend therefrom.

The location and dimensions of the plain 127 are selected to correspond to the desired location for the first row 111 and the desired dimension and orientation of the associated cutter elements 146. For example, the width of the plain 127 measured from the base 102 towards the nose height 106 is preferably selected to correspond to the desired longitudinal length of the associated cutter elements 146 measured from the base part 102. The radial distance 127 extending from the associated outside surface 104 is preferably selected to accommodate the elements. cutters 146 that have a desired height as measured from the same outer surface 104.

The location and dimensions of the second floor 128 and the third floor 129 are selected in a similar manner to correspond to the desired location for the respective first row 112, for the third row 113 and for the size of the associated cutter elements 148 and 150. The longitudinal spacing between the plane 127 and 128 generally corresponds to the first groove 116. The longitudinal spacing between the second plane 128 and the third plane 129 generally corresponds to the second groove 118.

For incorporation of the present invention as represented by Figure 4B, another step in the manufacture of the machined cutting structure 110 on the outer surface 104 of the cutter cone assembly 100a preferably includes a series of incline cuts to form the corrugations 141 in the first plane 127. For some applications, the inclined cutting tool (not expressly shown) may have a diameter approximately twice the width of the first plane 127. The first plane 127 can now be described as a corrugated fabric and is designated with the number 127a. Slanting techniques are preferably used to form the corresponding corrugations 142 in the second plane 128 and the corrugations 143 in the third plane 129. In a similar manner, the plane 128 can be described as the corrugated tissues 129a. A five-axis milling machine can also be used to form corrugated fabrics 172a, 128a and 129a.

For some types of downhole formations a machined cutting structure as shown in Figure 4B may be satisfactory for use with some rotating cone drills. For other types of downhole formations it may be preferable to interrupt or cut the corrugated fabrics 127a, 128a and 129a to form the respective cutter elements 146, 148 and 150.

For the embodiment of the present invention shown in Figure 4C, the corrugated fabrics 127a, 128a and 129a have been longitudinally cut to form the rows 111, 112 and 113 of the respective cutter elements 146, 148 and 150. Various milling techniques can be to be used to cut corrugated tissues 127a, 128a and 129a.

For this embodiment, the cutter elements 146, 148 and 150 have approximately the same general configuration. However, the dimensions and orientation associated with the cutter elements 146, 148 and 150 may vary depending on the dimensions associated with the respective plains 127, 128 and 129 and the respective machining techniques used to form the cutter elements 146, 148 and 150 Figures 5A, 5B and 5C show several steps associated with the machined section 90 in accordance with the teachings of the present invention for manufacturing the machined cutting structure 120 on the outer surface 104 of the cutter cone assembly 100b. Figures 6A, 6B and 6C show several steps associated with the machined section 90 in accordance with the teachings of the present invention for manufacturing the machined cutting structure 130 on the outer surface 104 of the cutter cone assembly 100c. The machined cutting structures 120 and 130 can be formed with the machined turns and the inclined cuts in substantially the same manner as described above with respect to forming the machined cutting structure 110 in Figures 5A, 5B and 5C.

Figure 5A shows the first concentric ring or plane 137 and the second concentric ring or plane 138 formed therein and extending radially from the outer surface 104. Figure 6A shows a first concentric ring or plane 167 and a second concentric ring or plain 168 formed in and extending radially from the respective outer surface 104. The location and dimensions of the first plains 137 and 167 are selected to correspond to the desired location for the respective first rows 121 and 131 and the size of the respective cutter elements 152 and 156. The location and dimensions of the respective second concentric flats 138 and 168 are selected in a similar manner to correspond to the desired location for the respective second rows 122 and 132 and the size of their respective rows. associated cutting elements 154 and 158.

Slanting techniques as described above with respect to corrugations 141, 142 and 143 as shown in Figure 4B can be satisfactorily used to form the corrugated fabrics 137a and 138a on the outside of the cutter cone assembly 100b and the corrugated fabrics 167a and 168a on the outside of the cutter cone assembly 100c. For incorporation of the present invention as shown in Figures 4B, 5B and 6B, the corrugated fabrics 127a, 128a, 129a, 137a, 138a, 167a and 168a generally have a sinusoidal configuration. For other applications, corrugated fabrics with other types of symmetrical and / or asymmetrical configurations may be formed on the outside of an associated cutter cone assembly. For incorporation of the present invention as shown in Figures 4C, 5C and 6C, the respective cutter elements in each row 111, 112, 113, 121, 122, 131 and 132 have approximately the same size, configuration and orientation. However, other applications of the present invention may allow the cutter elements in each row to vary in size and / or location with respect to other cutter elements in the same row. Also, the orientation of the cutter elements within each row can also be varied. For example, varying the diameter of the machine tool used to form the various inclined cuts may result in the modification of the dimensions of the resulting cutter element. Also, varying the size of the milling tool used to make each cut in the corrugated fabrics 127a, 128a, 129a, 137a, 138a, 167a and 168a may vary the dimensions of the resulting cutter elements.

Fig. 7 is an enlarged drawing showing a typical cutter element 152 in the first row 121 of the cutter cone assembly 100b. The cutter element 152 includes the base 172, the inner surface 174, the outer surface 176, the ridge 178, the front surface 180 and the rear surface 182. The outer surface 176 represents the part of the cutter element 152 located adjacent the wall 28. of the deep perforation 24. The front surface 180 represents the first part of the cutter element 152 which initially makes contact with the auger formation downwardly at the bottom of the deep hole 24. The crest 178 is a generally flat surface with a configuration of form of that or ogee form.

For incorporation of the present invention as shown in Figs. 4C, 5C and 6C the machined cutting structures 110, 120 and 130 preferably contain the cutter elements with a conopial shape configuration similar to the ridge 178 of the cutter element 152. As Resulting contact between the cutter cone assemblies 100a, 100b and 100c with the bottom of the deep hole 24 generates a significantly different pattern with the improved drilling action compared to the previous rotary cone bits.

The inner surface 174 includes the first surface 174a and the second surface 174b. The outer surface 176 also includes the first surface 176a and the second surface 176b. The configuration of the parts 174a and 176a are largely dependent on the configuration of the corresponding surfaces of the first floor 137. The surfaces 174b and 176b are largely determined by the type and size of the inclined cutting tool used for forming the corrugated tissue 137a. The surfaces 174b and 176b cooperate with each other and with the ridge 178 to generate what can be described as the plowing action or the cross-cutting action upon contacting the cutter element 152 with the bottom of the deep hole 24. surfaces 174a and 176a cooperate with one another to generate what can be described as a generally slicing action while cutter member 152 makes contact with the bottom and side of the deep hole 24. As a result of forming the cutter structures machined 110, 120 and 130 with a plurality of cutter elements having the downhole drilling action described previously, the requirement of the displaced cutter cone assemblies 100a, 100b and 100c is substantially reduced or eliminated.

The configuration of the front surface 180 and the rear surface 182 are largely dependent on the type of milling tool used to cut the corrugated fabric 137a into individual cutter elements 152. The respective angles formed between the outer surface 104 and the surfaces 174 , 176, 180 and 182 can be relatively steep. For example, depending on the type of inclined cutting tool used to form the corrugated fabric 137a, the resulting surfaces 174b and 176b may extend approximately normally from the outer surface 104.

Depending on the type of cutting tool machined and the milling tool used to form the cutter 152, the surfaces 174a, 176a, 180 and 182 may extend from the outer surface 104 at an angle of approximately one hundred ten degrees (110 ° C).

As a result for forming the relatively steep surfaces 174, 176, 180 and 182 extend from the outer surface 104, the contact area between the cutter element 152 and the bottom of the deep hole 24 represented by the ridge 178 may remain relatively constant in spite of the substantial wear of the cutter element 152. In a similar manner the contact between the surfaces 174, 176, 180 and 182 with the bottom of the deep hole 24 may also remain relatively constant. Therefore, the associated machine cutting structure 120 may remain relatively sharp to provide the desired downhole drilling action despite wear of the cutter elements 152 154.

The total contact area between the base 172 and the outer surface 104 is generally greater than the contact area associated with conventional milled teeth having approximately the same height and width. As a result, the cutter element 152 has sufficient strength required for the aggressive cutter profile associated with the surfaces 174, 176, 180 and 182 and the ridge 178.

The service life of the machined cutting structures 110, 120 and 130 can be improved by the addition of materials such as tungsten carbide or other materials appropriate for the selected wear areas. The addition of material from the selected wear areas of the machined cutting structures 100, 120 and 130 is known as "hard coating". Conventional methods for applying the hard coating include, for example, the techniques of application with a welding torch, placing a heat level of the welding torch to accumulate the thickest mass of each cutting element.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (19)

R E I V I N D I C A C I O N S

1. A method for manufacturing a cutting structure machined on a cone-shaped section associated with a cutter cone assembly of a rotating cone drill comprising: form a base part on the stretch; forming a nose on the opposite section from the base part; forming a conical surface generally tapered on the outside of the section extending from the base portion to the nose; forming at least one concentric ring extending circumferentially around the conical tapered surface and extending radially therefrom; Y forming a plurality of corrugations in the ring to provide a corrugated fabric.

2. The method as claimed in clause 1, further characterized in that it comprises forming the generally tapered conical surface and the continuous ring by a series of lathe turns.

3. The method as claimed in clause 1, further characterized in that it comprises forming the corrugated weave by a series of collapsing cuts at selected locations in the continuous ring.

4. The method as claimed in clause 1, further characterized in that it comprises cutting the corrugated tissue into multiple segments to form a plurality of cutter elements.

5. The method as claimed in clause 4, further characterized in that it comprises a series of machining cuts to form the respective cutter elements.

6. The method as claimed in clause 4, further characterized in that it comprises applying a hard hardening material layer to selected parts of each cutter element.

7. The method as claimed in clause 1, further characterized in that it comprises: forming a first concentric ring on one side of the base portion extending circumferentially around the generally tapered conical surface; Y forming a second concentric ring extending circumferentially around the tapered surface generally tapered at a location in the middle of the base portion of the nose.

8. The method as claimed in clause 1, further characterized in that it comprises: forming a first concentric ring on one side of the base portion extending circumferentially around the generally tapered conical surface; forming a second concentric ring extending circumferentially around the tapered surface generally tapered at a location in the middle of the base portion and the nose; Y forming a third concentric ring extending circumferentially around the tapered surface generally tapered to one side of the nose.

9. A rotating cone drill having at least one cutter cone assembly defined in part by a base portion, a nose and a generally tapered conical surface extending from the base portion to the nose, comprising: a machined cutting structure formed on the generally tapered conical surface, the cutting structure having a first row of cutter elements circumferentially positioned on one side of the base part and a second row of cutter elements positioned circumferentially on the conical surface generally tapered on a place in the middle of the base part and the nose, and each cutter element has a ridge with a cutter profile defined in part by a curve.

10. The rotary cone bit as claimed in clause 9, characterized in that the cutting structure further comprises a third row of cutter elements circumferentially positioned on the generally tapered conical surface adjacent to the nose.

11. The rotary cone bit as claimed in clause 9, further characterized in that it comprises each cutter having a pair of sides which extend essentially normal to the conical tapered surface.

12. The rotary cone bit as claimed in clause 9, characterized in that at least one cutter element further comprises a ridge having a curve of the conopial type.

13. The rotary cone bit as claimed in clause 9, further characterized in that it comprises at least one cutter element comprising a cutter profile having a slicing part and a plow part.

14. A method for manufacturing a rotating cone drill having at least one support arm with a cutter cone assembly rotatably mounted therein comprising: forming a base part on a cone-shaped section; forming a nose on the cone-shaped section; forming a generally tapered conical surface extending from the base portion to the nose; forming at least one concentric plain extending circumferentially around the tapered spherical surface and extending radially therefrom; form a plurality of corrugations in the plain; Y Cut the corrugated plain to form the respective cutter elements.

15. The method as claimed in clause 14, further characterized in that it comprises: forming at least two concentric planes extending circumferentially around the conical tapered surface and extending radially therefrom; Y forming the corrugation that has a generally sinusoidal configuration in each plain.

16. The method as claimed in clause 14, further characterized in that it comprises: forming at least three concentric flats extending circumferentially around the conical tapered surface and extending radially therefrom; form corrugations in each plain.

17. The method as claimed in clause 14, further characterized in that it comprises forming the generally tapered conical surface and the concentric plain by a series of planar turns.

18. The method as claimed in clause 14, further characterized in that it comprises forming the corrugations in the plain by a series of collapsing cuts.

19. The method as claimed in clause 14, further characterized in that it comprises applying a layer of hard coating material to selected parts of each cutting element. E S U M E N A rotary cone bit is provided with at least one cutter cone assembly having a machined cutting structure which maintains an effective cutting profile despite abrasion, erosion and / or wear of the associated cutter elements. The machined cutting structure can be formed in a d shape-shaped section generally by means of a series of furnace turns and / crash cuts. The cutting elements can be formed with an aggressive cutter profile. For an application, the crest of each cutter element has the general configuration of an ogee curve. A layer of hard coating material can be applied over the entire machined cutting structure or on selected parts thereof.