Abstract: A cutting element for an earth-boring tool includes a substrate and volume of superabrasive material positioned on the substrate. The volume of superabrasive material includes a cutting face having at least one recess extending into the volume of superabrasive material and/or at least one protrusion extending outward from the volume of superabrasive material. The volume of superabrasive material includes a first chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the first chamfer surface is located proximate a cutting edge of the volume of superabrasive material. A radial width of the first chamfer surface is between about 0.002 inch and about 0.045 inch. The volume of superabrasive material also includes a second chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the second chamfer surface is located adjacent the radially innermost edge of the first chamfer surface.

Abstract: A cutting element for an earth-boring tool includes a substrate and volume of superabrasive material positioned on the substrate. The volume of superabrasive material includes a cutting face having at least one recess extending into the volume of superabrasive material and/or at least one protrusion extending outward from the volume of superabrasive material. The volume of superabrasive material includes a first chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the first chamfer surface is located proximate a cutting edge of the volume of superabrasive material. A radial width of the first chamfer surface is between about 0.002 inch and about 0.045 inch. The volume of superabrasive material also includes a second chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the second chamfer surface is located adjacent the radially innermost edge of the first chamfer surface.

Abstract: A cutting element for an earth-boring tool includes a substrate and volume of superabrasive material positioned on the substrate. The volume of superabrasive material includes a cutting face having at least one recess extending into the volume of superabrasive material and/or at least one protrusion extending outward from the volume of superabrasive material. The volume of superabrasive material includes a first chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the first chamfer surface is located proximate a cutting edge of the volume of superabrasive material. A radial width of the first chamfer surface is between about 0.002 inch and about 0.045 inch. The volume of superabrasive material also includes a second chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the second chamfer surface is located adjacent the radially innermost edge of the first chamfer surface.

Abstract: In one aspect, a method of determining the presence of whirl for a rotating tool is disclosed that in one embodiment includes obtaining measurements (ax) of a parameter relating to the whirl of the tool along a first axis and measurements (ay) of the parameter along a second axis of the tool, determining a first whirl in a time domain for the tool using ax and ay measurements, determining a second whirl rate for the tool in a frequency domain from ax and ay measurements and determining the presence of the whirl from the first whirl rate and second whirl rate. The method further quantifies the whirl of the tool from the first and second whirl rates.

Abstract: A cutting element for an earth-boring tool includes a substrate and volume of superabrasive material positioned on the substrate. The volume of superabrasive material includes a cutting face having at least one recess extending into the volume of superabrasive material and/or at least one protrusion extending outward from the volume of superabrasive material. The volume of superabrasive material includes a first chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the first chamfer surface is located proximate a cutting edge of the volume of superabrasive material. A radial width of the first chamfer surface is between about 0.002 inch and about 0.045 inch. The volume of superabrasive material also includes a second chamfer surface having a peripheral edge and a radially innermost edge. The peripheral edge of the second chamfer surface is located adjacent the radially innermost edge of the first chamfer surface.

Abstract: A method of designing an earth-boring rotary drill bit includes designing a bit body and cutting elements of the drill bit such that features of the drill bit other than cutting elements engage and rub against a subterranean formation being drilled by the drill bit at depths-of-cut beyond, but close to, an intended median depth-of-cut, and such that the amount of rubbing area between such features and the formation increases at a relatively rapid rate as the depth-of-cut increases beyond the intended median depth-of-cut. Such methods may be employed to mitigate the occurrence of the “stick-slip” phenomenon during drilling. A method of fabricating a drill bit includes configuring a bit body and cutting elements in accordance with such a design. Earth-boring drill bits include a bit body and cutting elements so configured.

Abstract: Rock detritus created by a drag bit cutter shearing subterranean formation material may flow under the cutter and attach itself to the side surface of the cutter barrel by differential pressure-induced sticking, and dilate. This attached material, confined by hydrostatic pressure, can create and strengthen a barrier between the cutter and the virgin rock being cut. The detritus barrier absorbs bit weight and reduces cutter efficiency by impairing contact of the cutter with the virgin rock formation. Increasing friction between the rock detritus and a side surface of the cutter barrel inhibits detritus flow, reduces build up, and allows hydrostatic pressure to contribute to, rather than inhibit, the cutting process. Similar beneficial results may be obtained when hydrostatic pressure drilling fluid is permitted to communicate through holes in the side surface of the cutter, or through an otherwise permeable side surface alleviating detritus sticking due to differential pressure effects.

Abstract: In one aspect, a method of determining the presence of whirl for a rotating tool is disclosed that in one embodiment includes obtaining measurements (ax) of a parameter relating to the whirl of the tool along a first axis and measurements (ay) of the parameter along a second axis of the tool, determining a first whirl in a time domain for the tool using ax and ay measurements, determining a second whirl rate for the tool in a frequency domain from ax and ay measurements and determining the presence of the whirl from the first whirl rate and second whirl rate. The method further quantifies the whirl of the tool from the first and second whirl rates.

Abstract: Discrete Element Modeling (DEM) of rock subject to high confining pressures, such as in a subterranean drilling environment, may be used to predict performance of cutting structures used in drill bits and other drilling tools, as well as of the tools themselves. DEM may also be used to create “virtual” rock exhibiting specific drillability characteristics with or without specific reference to any actual rock, for purposes of assessing cutting efficiency of various cutting structure configurations and orientations, as well as of drilling tools incorporating same.

Abstract: Rock detritus created by a drag bit cutter shearing subterranean formation material may flow under the cutter and attach itself to the side surface of the cutter barrel by differential pressure-induced sticking, and dilate. This attached material, confined by hydrostatic pressure, can create and strengthen a barrier between the cutter and the virgin rock being cut. The detritus barrier absorbs bit weight and reduces cutter efficiency by impairing contact of the cutter with the virgin rock formation. Increasing friction between the rock detritus and a side surface of the cutter barrel inhibits detritus flow, reduces build up, and allows hydrostatic pressure to contribute to, rather than inhibit, the cutting process. Similar beneficial results may be obtained when hydrostatic pressure drilling fluid is permitted to communicate through holes in the side surface of the cutter, or through an otherwise permeable side surface alleviating detritus sticking due to differential pressure effects.

Abstract: Rock detritus created by a drag bit cutter shearing subterranean formation material may flow under a cutter and attach itself to a side surface of a cutter barrel by differential pressure-induced sticking, and dilate. This attached material, confined by hydrostatic pressure, can create and strengthen a barrier between the cutter and virgin rock being cut. The detritus barrier absorbs bit weight and reduces cutter efficiency by impairing contact of the cutter with the virgin rock formation. Increasing friction between the rock detritus and the side surface of the cutter barrel inhibits detritus flow, reduces build up, and allows hydrostatic pressure to contribute to, rather than inhibit, the cutting process. Similar beneficial results may be obtained when hydrostatic pressure drilling fluid is permitted to communicate through holes in the side surface of the cutter, or through an otherwise permeable side surface alleviating detritus sticking due to differential pressure effects.

Abstract: To improve drilling performance, a drilling fluid is selected based on one or more criteria and to have at least one target characteristic. Drilling equipment is used to drill a wellbore, and the selected drilling fluid is provided into the wellbore during drilling with the drilling equipment. The at least one target characteristic of the drilling fluid includes an ability of the drilling fluid to penetrate into formation cuttings during drilling to weaken the formation cuttings.

Abstract: To improve drilling performance, a drilling fluid is selected based on one or more criteria and to have at least one target characteristic. Drilling equipment is used to drill a wellbore, and the selected drilling fluid is provided into the wellbore during drilling with the drilling equipment. The at least one target characteristic of the drilling fluid includes an ability of the drilling fluid to penetrate into formation cuttings during drilling to weaken the formation cuttings.

Abstract: Discrete Element Modeling (DEM) of rock subject to high confining pressures, such as in a subterranean drilling environment, may be used to predict performance of cutting structures used in drill bits and other drilling tools, as well as of the tools themselves. DEM may also be used to create “virtual” rock exhibiting specific drillability characteristics with or without specific reference to any actual rock, for purposes of assessing cutting efficiency of various cutting structure configurations and orientations, as well as of drilling tools incorporating same.

Abstract: In one embodiment an apparatus is disclosed that includes a tool in a wellbore. A probe is extendable from the tool to contact a wall of a formation surrounding the wellbore. A tube substantially surrounds the probe wherein the tube is extendable into the formation surrounding the wellbore. In another embodiment a method for reducing contamination of a sample of a formation fluid is disclosed that includes extending a probe to contact a wall of a formation. A barrier tube that substantially surrounds the probe is extended into the formation thereby restricting a flow of a contaminated reservoir fluid that would otherwise come from near-wellbore regions above and below the probe from going toward the probe.

Abstract: An earth boring bit has rolling cones rotatably mounted to the bit legs. Each cone has conical bands extending around the exterior. Holes are formed in each of the bands. Compacts are press-fitted into the holes, each having a cutting tip that projects from the conical band. Flats are formed in the conical bands, each flat extending between adjacent compacts.

Abstract: A tri-cone earth-boring bit has nozzles oriented for improved cone cleaning, bottom cleaning and cuttings evacuation. Each of the nozzles is oriented to discharge across a trailing side of a cone at a point considerably inboard of the borehole wall. Each nozzle has an outlet located radially outward from the bit axis a distance that is at least equal to a distance from a top dead center of the heel row of each of the cones to the bit axis. Also, each of the nozzles is oriented to discharge drilling fluid along a line that contacts the borehole bottom at a distance that is no greater than a distance from a bottom dead center of an outermost of the inner rows of the cone to the bit axis. A portion of the drilling fluid discharged from each nozzle will pass by more than one of the rows of the cones.

Abstract: Disclosed herein is an earth boring bit of otherwise conventional construction except for the bearing and cutter retention. A snap ring is used to retain the cutter, the grooves that receive the ring and the ring construction being such that the ring is forced into the retainer groove when the cone is thrust inward. The ring cannot therefore accidentally return to its assembly position to permit cutter loss. This enables the use of exclusively frictional bearings and retainer means of exceptional strength and reliability.