Abstract: A method for designing a roller cone drill bit having a plurality of cutting elements in a row. The method includes defining a pitch pattern for the plurality of cutting elements such that a first group of adjacent cutting elements are arranged in a first pitch and a second group of adjacent cutting elements are arranged in a second pitch in the row; evaluating the pitch pattern of the plurality of cutting elements in the row; and modifying at least one of the plurality of cutting elements, based on the evaluating the pitch pattern of the plurality of cutting elements.

Abstract: A method of forming milled teeth on a roller cone of a milled tooth roller cone rock bit includes shaping a crest of a chisel shaped milled tooth on the roller cone. The crest is shaped such that the crest has a convex profile from one corner to an opposite corner of the crest. Such a crest is adapted to produce at least one of a convex axial stress distribution, a substantially even axial stress distribution, and a substantially smooth axial stress distribution. Further, the forming includes radiusing each of the corners at the ends of the crest of the chisel shaped milled tooth.

Abstract: Provided are methods, data communication apparatus and computer programs for managing communications between a remote communication manager and a set of communications managers in an associated group. The group of communication managers have shared access to resources which enable any communication manager in the group to recover from failures experienced by another communication manager in the group. In particular, recovery of failed inbound and outbound channels is achieved with the advantage of improved availability of data transmissions. Preferably, the recovery uses synchronization information to ensure that data is recovered to a consistent state to that channel recovery is achieved without loss of data integrity.

Abstract: The invention is a drill bit that has a bit body, at least one roller cone attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on the at least one roller cone. At least one bit design parameter is selected so that the cutting elements wear in a selected manner when drilling an earth formation. The invention is also a method for designing a drill bit that has at least one roller cone and a plurality of cutting elements. The method includes several steps, beginning with selecting initial bit design parameters. The drill bit is then simulated drilling at least one selected earth formation. The wear induced change in the cutting element geometry is determined and the simulated bit is adjusted to reflect the wear. The selecting, simulating, determining, and adjusting are repeated and at least one bit design parameter of the drill bit is adjusted until at least one performance parameter of the drill bit is optimized.

Abstract: A method of forming milled teeth on a roller cone of a milled tooth roller cone rock bit includes shaping a crest of a chisel shaped milled tooth on the roller cone. The crest is shaped such that the crest has a convex profile from one corner to an opposite corner of the crest. Such a crest is adapted to produce at least one of a convex axial stress distribution, a substantially even axial stress distribution, and a substantially smooth axial stress distribution. Further, the forming includes radiusing each of the corners at the ends of the crest of the chisel shaped milled tooth.

Abstract: Disclosed are a variety of arcuate-shaped inserts for drill bits, and in particular, for placement in rolling cone cutters of drill bits. The arcuate inserts include 360° or ring-shaped inserts, as well as inserts of smaller arcuate length. The arcuate inserts are suitable for use in all surfaces of the rolling cone cutter, and in other locations in drill bits, and may have specialized cutting surfaces and material enhancements to enhance their cutting duty performance. Certain arcuate inserts may include stress relieving discontinuities such that, upon assembly into the cone or during drilling, the arcuate inserts may fragment in a controlled and predicted manner into shorter arcuate lengths.

Abstract: A method for designing a drill bit that involves simulating a drill bit having cutting elements disposed thereon is provided.

Abstract: A method for designing a drill bit that has at least one roller cone and a plurality of cutting elements, including selecting initial bit design parameters. Drilling simulations are then used to determine wear, and the simulated drill bit is changed to reflect the determined wear. Then, at least one design parameter is adjusted. The simulation, determination, change of the simulated drill bit, and adjustment may be repeated until at least one performance parameter of the drill bit is optimized. A drill bit can be designed using such a method.

Abstract: A method for evaluating a cutting arrangement for a drill bit includes selecting a cutting element arrangement for the drill bit and calculating a score for the cutting arrangement. This method may be used to evaluate the cutting efficiency of various drill bit designs. In one example, this method is used to calculate a score for an arrangement based on a comparison of an expected bottomhole pattern for the arrangement with a preferred bottomhole pattern. The use of this method has lead to roller cone drill bit designs that exhibit reduce tracking over prior art bits.

Abstract: A method for optimizing drilling performance of a roller cone drill bit is disclosed. The method includes simulating drilling with the bit in a selected earth formation to determine at least one drilling performance parameter. The orientation of at least one non-axisymmetric cutting element on the bit is adjusted and the simulating the drilling and determining the at least one performance parameter are repeated. The adjusting and simulating the drilling are repeated until the at least one performance parameter is determined to be at an optimum value. In one embodiment, the performance parameter includes rate of penetration.

Abstract: A method for evaluating a cutting arrangement for a drill bit includes selecting a cutting element arrangement for the drill bit and calculating a score for the cutting arrangement. This method may be used to evaluate the cutting efficiency of various drill bit designs. In one example, this method is used to calculate a score for an arrangement based on a comparison of an expected bottomhole pattern for the arrangement with a preferred bottomhole pattern. The use of this method has lead to roller cone drill bit designs that exhibit reduce tracking over prior art bits.

Abstract: Disclosed are a variety of arcuate-shaped inserts for drill bits, and in particular, for placement in rolling cone cutters of drill bits. The arcuate inserts include 360 degree or ring-shaped inserts, as well as inserts of smaller arcuate length. The arcuate inserts may include stress relieving discontinuities such that, upon assembly into the cone, the arcuate inserts fragment in a controlled and predicted manner into shorter arcuate lengths. The arcuate inserts are suitable for use in all surfaces of the rolling cone cutter, and in other locations in drill bits, and may have specialized cutting surfaces and material enhancements to enhance their cutting duty performance.

Abstract: The invention is directed to a roller cone drill for drilling earth formations and a method of using the same. The drill bit includes a bit body and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. The drill bit further includes a plurality of cutting elements disposed on each of the roller cones, an offset of at least about 0.375 inches; and a journal angle less than about thirty degrees. In one embodiment, the drill bit includes three roller cones. In another embodiment, the cutting elements of the bit are arranged on each cone so that cutting elements on adjacent cones intermesh between the cones.

Abstract: A cutter element is disclosed having a rounded apex offset from the center line of the insert and having a relatively broad and blunt front face and a narrower, more rounded rear face. The cutter element may be disposed in the outermost inner row of a rolling cone cutter of a bit with the broader front face facing the borehole side wall so as to resist off center wear and resultant bit whirl. When placed in inner rows and oriented with the broader and flatter front face being the first portion of the cutting surface to engage the borehole, enhancements in bit durability may be achieved, particularly when drilling through formations of multiple hardness.

Abstract: A drill bit has a bit body and at least one roller cone rotatably mounted on the bit body. The cone has a plurality of milled teeth at selected locations on the cone. At least one of the milled teeth has a substrate having a convex crest and a layer of hardfacing applied to the convex crest. The convex crest is adapted to produce at least one of a convex axial stress distribution, a substantially even axial stress distribution, and a substantially smooth axial stress distribution.

Abstract: A novel rolling cone rock bit includes a plurality of PDC or other cutters mounted to the leg of the drill bit and positioned to cut the troublesome corner of the bottomhole. The plurality of cutters may be the primary cutting component at gage diameter, or may be redundant to gage teeth on a rolling cutter that cut to gage diameter. Consequently, the occurrence of undergage drilling from the wear and failure of the gage row on a rolling cutter is lessened. Another inventive feature is the inclusion of a mud ramp that creates a large junk slot from the borehole bottom up the drill bit. The resulting pumping action of the drill bit ramp speeds up the removal of chips or drilling cuttings from the bottom of the borehole, reduces the level of hydrostatic pressure at the bottom of the borehole and minimizes the wearing effect of cone inserts regrinding damaging drill cuttings.

Abstract: New cutting structures for roller cone drill bits are disclosed. In one aspect, a drill bit includes a bit body, roller cones attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on each of the roller cones, such that axial force on the bit during drilling is substantially balanced between the cones. In another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that the amount of work performed by each cone during drilling is substantially the same as the amount of work performed by each of the other cones. In yet another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that distribution of axial force on the bit is optimized. Additional aspects of the invention are also disclosed.

Abstract: Disclosed are a variety of arcuate-shaped inserts for drill bits, and in particular, for placement in rolling cone cutters of drill bits. The arcuate inserts include 360 degree or ring-shaped inserts, as well as inserts of smaller arcuate length. The arcuate inserts may include stress relieving discontinuities such that, upon assembly into the cone, the arcuate inserts fragment in a controlled and predicted manner into shorter arcuate lengths. The arcuate inserts are suitable for use in all surfaces of the rolling cone cutter, and in other locations in drill bits, and may have specialized cutting surfaces and material enhancements to enhance their cutting duty performance.

Abstract: The invention relates to a roller cone drill bit for drilling earth formations. The drill bit includes a bit body and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. Each roller cone of the bit includes a truncated apex and a side surface. The drill bit further includes a plurality of cutting elements disposed on the side surface of each cone. The cutting elements on at least one cone are arranged such that at least one cutting element on that cone extends past an axis of rotation of the bit body as the bit is rotated. In one embodiment, the drill bit includes three cones and the cutting elements are arranged on the cones so that cutting elements on adjacent cones intermesh between the cones.

Abstract: The invention is a drill bit that has a bit body, at least one roller cone attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on the at least one roller cone. At least one bit design parameter is selected so that the cutting elements wear in a selected manner when drilling an earth formation.