Abstract: A roller cone bit may be used as a rotating drag bit by treating the roller cones as carriers for a plurality of distinguishable types of drag cutters. The roller cones are each coupled to a mechanism which selectively allows rotation of the roller cones. The roller cones are otherwise fixed and as the bit is rotated, the drag cutters are brought into engagement with the rock. However, where the roller cones are selectively allowed to rotate, rotation of the drag bit rotates the roller cones to bring a second set of drag cutters into a configuration for cutting the rock formation. A mechanism then selectively locks the roller cones to prevent further rotation, keeping the second set of drag cutters fixed in place. By selectively permitting and preventing rotation of the roller cones, a plurality of sets of drag cutters can be brought into a configuration for cutting the rock.

Abstract: In a method of assessing drilling conditions during a drilling operation measurements of torque applied (TOR), weight on bit (WOB), rate of penetration (ROP), and rotation speed (ROT) are gathered. Computed therefrom is a history (60, 61) of points (x, y) where x=(TOR/WOB) and y=(ROP/ROT).sup..gamma. : .gamma. being a derived constant indicative of down hole geometry. Trends in this history are monitored to assess drilling conditions. For example in soft plastic rock migration 62 towards the origin and in hard plastic rock migration 63 towards the abscissa is indicative of drill bit wear.

Abstract: The present invention relates to a method and apparatus for detecting excessive wear of a rotatable bit used in drilling. In particular, the apparatus can detect loss of gauge or bearing failure in a bit. The method is accomplished by connecting a restricting means in the drill bit that can be manipulated to reduce the flow of drilling fluid through at least one port in the drill bit. A wire is connected between a sensor which senses wear and the restriction means to cause the restriction means to reduce the flow of drilling fluid and thereby signal the surface by the reduced flow as an indication of wear.

Abstract: A method for measuring the wear of milled tooth bits during oilwell drilling uses surface and subsurface wellsite sensors to determine averaged values of penetration rate, rotation speed and MWD (measurements-while-drilling) values of torque and weight-on-bit to obtain a real time measurement of tooth wear, drilling efficiency and the in situ shear strength of the rock being drilled.

Abstract: A hard metal wear insert to be force fitted into a steel body of a tool or stabilizer which has a serrated cylindrical side surface, as in the prior art, but is provided with air relief passages on the sides to relieve air in the receiving recess as the insert is driven in. A diametrical cross-passage between the air relief passages aids in the expulsion of air and provides a fracture line for destructive removal of the inserts. A central axial passage in conical form allows ready inspection of progressive wear as well as functioning to vent the interior end to prevent excessive air pressure in the heating of the body. A receiving recess in the body is shaped to provide a bottom surface to seat the insert solidly while permitting the air relief passages to function.

Abstract: A lubrication failure detection system for utilization with an earth boring drilling system having at least one rotary drill bit coupled to a drill string, the drill string having an internal passage adapted to receive drilling fluid under pressure. A lubrication reservoir is disposed near said rotary drill bit and coupled to bearing surfaces within said rotary drill bit by a lubrication passageway. A flexible membrane separates the lubrication reservoir from drilling fluid within the annulus formed by the rotary drill bit and distends inward in response to the pressure of the drilling fluid. The distention of the membrane forces lubricant into the lubrication passageway and when the membrane has distended to a selected point, the membrane actuates a mechanism which opens an orifice into the internal passage of the drill string, thereby abruptly decreasing the pressure of the drilling fluid within the drill string.

Abstract: Impending bearing failure, seal failure and drilling an undergage well bore, among other things, are immediately detected by sensing the presence of aqueous drilling fluid in a lubricant or other type of sealed cavity of a drilling tool or the like during a downhole drilling operation in an environment of aqueous fluid. Electrical conduction elements are preferably employed to sense the presence of the aqueous fluid. The electrical conduction means may employ a soluble anhydrous conductive material which, when in contact with the aqueous drilling fluid, dissolves or becomes an electrical conductor to signal the presence of the aqueous fluid. The aqueous fluid may additionally serve as an electrolyte between two dissimilar metals, thereby forming a galvanic cell, or as a conductor between a pair of contact terminals. In a drilling operation, a signal is preferably transmitted from a downhole location to the surface of the earth by mud pulse telemetry.

Abstract: There is disclosed an ablatible drill comprising a soft or frangible matrix having embedded therein a multiplicity of hard inclusions which act as cutting teeth. During drilling, the matrix gradually wears away so that worn inclusions are circulated out of the hole and fresh inclusions are exposed as new cutting teeth. A plurality of joints of the ablatible drill are interconnected on the bottom of a drill string. The comminuted material of each joint of the ablatible drill provides a characteristic distinguishable from the comminuted material of adjacent joints so that in examination of the circulated returns provides an indication of which joint is then being drilled.

Abstract: A roller reamer body is provided with junk receiving pockets that are downward extensions of the body cavities in which the rollers and their shaft mounting blocks are disposed. The slots have upwardly slidably openable or removable outside wall panels so that junk can be dumped from the slots while the reamer is still vertical in the drill string, making it unnecessary to disconnect the reamer to dump the junk.

Abstract: There is disclosed a down-hole drilling motor having a connection to the drill bit, such that, when desirable or necessary, fluid may be circulated in the bore by means of the motor to clean out undue accumulation of cuttings, or for other reasons, while at the same time the bit is stopped, thereby saving wear on the bit and bit drive parts. When the motor is disconnected from the drill shaft, the drill shaft may be locked to the drill pipe so that the bit may be rotated by turning the drill pipe from the top of the bore with the conventional rotary table to permit the operator to drill his way out if the drill is stuck or to roll the bit out from under a ledge under which it might be caught during drilling.

Abstract: A turbo drill which is connected to a string of drill pipe as a rotating shaft for driving a drill bit which may be a rotary bit or a high speed solid head diamond bit. The turbine section has rotor and stator blades which are cresent shaped in cross section with each blade having an exit angle of 14.degree. - 23.degree. for maximum turbine efficiency. The bearing shaft is provided with chevron rotary seals positioned below the rotary bearings carrying both radial and vertical thrust. Fluid lubricant fills the space from the rotary seals to a predetermined level above the bearings. A piston seals the lubricant chamber and is pressurized by drilling fluid (i.e. mud) flowing through the tool. A layer of lubricant fluid overlies the first piston and has a second piston covering said fluid and transmitting pressure from the drilling fluid to the lubricant fluid surrounding the bearings.

Abstract: A method for determining the amount and character of rotary drilling bit wear without interruption of the drilling operation.The method comprises flowing a drilling fluid through the borehole and around the bit with sufficient velocity to remove the formation and bit cuttings as well as dust and other fragments knocked or worn loose from the bit, placing a magnetic in close proximity to the recovered material such that a portion of the ferrous cuttings, fragments and dust are attracted to the surface of the magnet, removing the ferrous cuttings, fragments and dust from the magnet and examining them under an optical microscope to enable observation of their size, shape and color, and comparing the quantity, size, shape and color of the recovered ferrous material with the quantity, size, shape and color of ferrous cuttings, fragments and dust indicative of known conditions of bit wear.scale.