Abstract: A loop antenna assembly is provided that can include a loop antenna with one of more magnet wires encased in a non-magnetic flexible sheath and mounted to a transceiver block that is mountable to a tool body, where the loop antenna can at least partially encircle the tool body. The loop antenna can include a plurality of magnet wires each individually encased in the sheath, with a metal adaptor attached to each end. The magnet wire can be coated with thin insulation, thin enamel insulation, and/or a polymer film. A plane of the loop antenna can be perpendicular relative to the longitudinal axis or at an obtuse angle relative to the longitudinal axis. A non-magnetic locating ring positioned in the loop antenna assembly can secure the loop antenna of the assembly about the tool body.

Abstract: Movable transducer designs used in downhole environments increase the efficiency of the transmitter and receivers, thereby obtaining improved logging data. In one embodiment, the transmitter/receivers are tilted/rotated to direct the strongest acoustic wave pressure to the critical path for increasing signal strength. In other embodiments, the transmitter/receiver may be extended outwardly toward the formation, or retracted inwardly from the formation. An adaptive algorithm is provided to rotate the transmitter/receiver to match the critical angle when the formation slowness changes. Also, a transmitter/receiver port may be designed to have a cone-shape that matches the impedance of the acoustic wave to the surrounding environment.

Abstract: An antenna shield latches around a mandrel or wellbore tubular to protect an antenna carried by the mandrel. The antenna shield opens to facilitate installation over the mandrel, and closes the around the antenna to provide robust protection from the downhole environment. Radial sections of the antenna shield are coupled to one another such that the antenna shield maintains a one piece construction, and the sections may pivot to move the antenna shield between open and closed configurations. Readily opening and closing the antenna shield facilitates maintenance and repair of the antenna and reusability of the antenna shield. Other components of a logging tool system, e.g., stabilizers, may also be provided with a similar latch mechanism for coupling to an outer diameter of the wellbore tubular.

Abstract: A downhole oscillation tool and method for axially vibrating a drill bit. In some embodiments, modular actuation assemblies may be provided, which may be readily interchanged between a housing and a shaft to axially vibrate the shaft with respect to the housing. Modular actuation assemblies may be mechanical, hydraulic, electric, or piezoelectric, for example, and may be characterized by differing oscillation frequencies. In some embodiments, a piezo element may be provided between the housing and the shaft.

Abstract: A resistivity logging tool includes a resistivity antenna and an antenna shield having a longitudinal slot segments interconnected to form an elongated slot with an elongated slot length that is longer than the length of the sleeve in which the slot segments are formed thereby enhancing electromagnetic wave strength propagated through the shield. Longitudinal slot segments may be interleaved to maximize the total number of elongated slots.

Abstract: A loop antenna assembly is provided that can include a loop antenna with one of more magnet wires encased in a non-magnetic flexible sheath and mounted to a transceiver block that is mountable to a tool body, where the loop antenna can at least partially encircle the tool body. The loop antenna can include a plurality of magnet wires each individually encased in the sheath, with a metal adaptor attached to each end. The magnet wire can be coated with thin insulation, thin enamel insulation, and/or a polymer film. A plane of the loop antenna can be perpendicular relative to the longitudinal axis or at an obtuse angle relative to the longitudinal axis. A non-magnetic locating ring positioned in the loop antenna assembly can secure the loop antenna of the assembly about the tool body.

Abstract: A downhole oscillation tool and method for axially vibrating a drill bit. In some embodiments, modular actuation assemblies may be provided, which may be readily interchanged between a housing and a shaft to axially vibrate the shaft with respect to the housing. Modular actuation assemblies may be mechanical, hydraulic, electric, or piezoelectric, for example, and may be characterized by differing oscillation frequencies. In some embodiments, a piezo element may be provided between the housing and the shaft.

Abstract: An acoustic receiver and method for acoustic logging. The acoustic receiver comprises a housing and a sensor subassembly, which is located within the housing. The sensor subassembly comprises a mount and a cylindrical piezoelectric crystal coupled to the mount. The sensor subassembly also comprises an isolation ring positioned between one of the ends of the cylindrical piezoelectric crystal and the mount. The isolation ring directly engages the crystal and the mount. The method of acoustic logging comprises receiving an acoustic signal using an acoustic receiver, which comprises a cylindrical piezoelectric crystal coupled to a mount without an adhesive material. The method also comprises converting the acoustic signal into an electrical signal by the cylindrical piezoelectric crystal and transmitting the electrical signal to a processor via a conductor coupled to the cylindrical piezoelectric crystal.

Abstract: Movable transducer designs used in downhole environments increase the efficiency of the transmitter and receivers, thereby obtaining improved logging data. In one embodiment, the transmitter/receivers are tilted/rotated to direct the strongest acoustic wave pressure to the critical path for increasing signal strength. In other embodiments, the transmitter/receiver may be extended outwardly toward the formation, or retracted inwardly from the formation. An adaptive algorithm is provided to rotate the transmitter/receiver to match the critical angle when the formation slowness changes. Also, a transmitter/receiver port may be designed to have a cone-shape that matches the impedance of the acoustic wave to the surrounding environment.

Abstract: A downhole oscillation tool and method for axially vibrating a drill bit. In some embodiments, modular actuation assemblies may be provided, which may be readily interchanged between a housing and a shaft to axially vibrate the shaft with respect to the housing. Modular actuation assemblies may be mechanical, hydraulic, electric, or piezoelectric, for example, and may be characterized by differing oscillation frequencies. In some embodiments, a piezo element may be provided between the housing and the shaft.

Abstract: A downhole oscillation tool and method for axially vibrating a drill bit. In some embodiments, modular actuation assemblies may be provided, which may be readily interchanged between a housing and a shaft to axially vibrate the shaft with respect to the housing. Modular actuation assemblies may be mechanical, hydraulic, electric, or piezoelectric, for example, and may be characterized by differing oscillation frequencies. In some embodiments, a piezo element may be provided between the housing and the shaft.

Abstract: One example of an acoustic signal attenuator for LWD/MWD A logging systems can be implemented as an acoustic well logging tool positionable in a wellbore. The tool includes a longitudinal tool body. An acoustic signal transmitter and an acoustic signal receiver are mounted in the tool body and spaced longitudinally apart from each other. An acoustic signal attenuator which includes multiple slots formed in an outer surface of a portion of the tool body is positioned between the transmitter and the receiver. Each slot includes multiple protrusions extending from an inner surface of the slot into the slot. In operation, the multiple protrusions in each slot operate to attenuate an acoustic signal propagating from the transmitter to the receiver through the tool body.