Abstract: The present invention relates to a measurement-while-drilling (MWD) tool having a pressure compensation system and reservoir segregated from fluid integration with actuator mechanism lubricants. The MWD tool can also be serviced on the rig floor without the need to drain, reseal and charge the compensation system.

Abstract: The present invention relates to a measurement-while-drilling tool [2] with a mechanically driven poppet [216] which eliminates the flow of drilling fluid through the tool, and reliance on surface supplied hydraulic force to activate the poppet [216]. The present invention eliminates the pilot valve system, and generates a fluid pulse from a direct drive relationship between a reversible motor [414], actuator [300], and poppet valve [216]. A pulser [200] has a push rod [214] slidably located inside. Poppet [216] is located on the push rod [214]. Actuator [300] is connected to the pulser [200], and has a ball screw [334] mechanically connected [330] to the push rod [214]. An electric motor [414] and gear train is operatively connected [338] [340] [342] to the ball screw [334]. Motor [414] generates linear movement of the poppet [216] in relation to an orifice [112] to restrict flow and generate a pulse.

Abstract: The present invention relates to a measurement-while-drilling (MWD) tool having a pressure compensation system and reservoir segregated from fluid integration with actuator mechanism lubricants. The MWD tool can also be serviced on the rig floor without the need to drain, reseal and charge the compensation system.

Abstract: A modular kerfing rock drilling bit (10) is presented. Drill bit (10) comprises a bit body (12) having a connection (14) for attachment to a drill string member. A base portion (16) below the connection (14) has an outer portion (18) and a bottom (20). Slots (22) are formed in the base portion (16). A cutter assembly (100) comprises a leg (110) insertable into the slot (22) of the bit body (16). A journal (126) extends angularly downward and inward from the leg (110) for bearing support of a cone (180) rotatably mounted on the journal (126). A plurality of cutters (182) extend outward from the surface of the cone (180). A kerfing segment (140) extends downward from the leg (110) beyond the cone (180). A plurality of kerf cutters (142) are attached to the bottom of the kerfing segment (140).

Abstract: A method and apparatus for drilling a well is set forth. In one aspect, a typical drill stem is assembled from a set of drill pipe and delivers a flow of drilling mud to the drill bit. A smaller tubing string is placed on the interior and connects to a mixing valve just above the drill bit. A gas flow is placed in the tubing which flows to the mixing valve where the gas is mixed in a desired ratio with the drilling mud so the mud weight is reduced, and thereby enables drilling, at a faster rate with an underbalanced condition. Steps are set forth in which the pressure is changed to an overbalanced condition.

Abstract: This disclosure sets forth an electromagnetic measurement-while-drilling telemetry system, and more particularly, a telemetry system which utilizes a gas filled, metallic, tubular wave guide as a conduit between a downhole transmitter element and a surface receiver element. The tubular wave guide is positioned preferably concentrically within a drill string such as coiled tubing or conventional, rigid drill pipe. A valving system allows the tubular wave guide to be filled with gas, while the annulus between the inner conduit and the drill string is filled with drilling fluid. The preferred transmission frequency in the 20 to 40 gigaHertz range using a transverse electrical-circular pattern (TEO.sub.0.1) wave transmission mode. Data transmission rates using the disclosed system are much greater that those obtained with mud pulsing systems, and attenuation rates are much lower than those obtained with electromagnetic systems using liquid filled wave guides.

Abstract: This invention relates to an improved roller cone coring bit that includes spiral stabilizer blades on the bit body. The spiral stabilizer blades reduce the whirling tendency of the bit, thereby enhancing the ability to cut and recover a continuous core.

Abstract: This describes a method for improved data signaling equipment for use with well-drilling tools for rapidly sending measurements made down the hole in the wellbore to the surface without the need of an electric cable. A special well tool is connected into a drill string having a drill bit coupled thereto for drilling a borehole. During normal drilling operations, the data-sending equipment is not in operation, and the main body of circulating or drilling fluid is passed through a main valve in the downhole tool and bypasses a pressure-changing unit. A sensing unit is incorporated in the downhole tool and measures downhole parameters. When it is desired to send these data to the surface, the main circulation of drilling fluid is stopped and the bypass valve closed. Then, a small amount of fluid is supplied to the "closed" drill string from a substantially constant-pressure source.