Abstract: Example vibrating helical spring sensors and methods to operate the same are disclosed. A disclosed example apparatus includes a housing, a helical spring held in tension, a flowline to expose the helical spring to a fluid, a magnet to expose the helical spring to a magnetic field, and a wire to electrically conduct an actuating current through the helical spring to displace the helical spring.

Abstract: Vibrating wire viscometers are described. Some example vibrating wire viscometer housings include a flowline through the housing to expose a first wire to a downhole fluid, a cavity in the housing to hold a magnet and to conduct one or more additional wires from the flowline to a signal generator, first and second electrically conductive posts mechanically coupled to the housing to hold the first wire in tension within the flowline, and a seal mechanically coupled to the housing to prevent access to the magnet by the downhole fluid.

Abstract: Vibrating wire viscometers are disclosed. An example vibrating wire viscometer includes first and second electrically conductive tubes, where the first tube is at least partially inserted into the second tube, and where the first and second tubes are coupled via an electrically insulating bonding agent. The example viscometer further includes first and second electrically conductive pins inserted into respective ones of the first and second tubes, and an electrically conductive wire fastened to the first and second pins to vibrate in a downhole fluid to determine a viscosity of the downhole fluid.

Abstract: Methods and systems utilizing seismic sensors configured or designed for use in seismic signal detection. An electrical current is applied to a seismic sensor such that the moving coil is located at a neutral position relative to the magnetic field in the seismic sensor to compensate for gravitational acceleration.

Abstract: Subterranean sensing devices configured or designed for downhole use to sense a local condition in the well. The sensing devices comprise one or more transistor having at least one carbon nanotube field effect transistor (CNT FET) configured or designed for operation downhole, within a borehole.

Abstract: A pressure transducer for high-pressure measurements comprising a housing and a piezoelectric resonator located in the housing, wherein the resonator comprises double rotation cut piezoelectric material configured or designed for vibrating in the fundamental tone of dual modes of the fast and slow thickness-shear vibrations.

Abstract: Methods and related systems are described relating to a sealed acoustic transducer assembly for use in a wellbore is provided. One or more acoustic transducer elements, which can be receivers or transmitters, are housed in an elongated fluid filled sealed container. The sealed container is adapted to be removeably mounted to a portion of a drill collar. The container, which for example can be made of thin corrugated metal or rubber, includes flexible portions along the length of the container which allows for volume changes when exposed to changes in external pressure and/or temperature.

Abstract: Methods and apparatus for facilitating optical communications and sensing, with downhole optical or other sensors, in high temperature oilfield applications. The apparatus can include a downhole telemetry cartridge for downhole use at temperatures in excess of about 115 degrees Celsius. The apparatus can also include a downhole light source optically connected to the telemetry cartridge. The light source may include at least one remotely pumped laser optically connected to a surface pump laser via optical fiber(s). The remotely pumped laser may drive the downhole optical or other sensors for their operations.

Abstract: Methods and systems for compensating temperature measurements by a temperature gauge comprising a first temperature sensor and a second reference temperature sensor, having different thermal properties, located in the same temperature environment to be measured. The methods and systems compensate for errors in the measured temperatures due to variations in the reference sensor caused by temperature effects.

Abstract: A downhole characterization apparatus for formation fluids is provided. The apparatus comprises a downhole tool including a flowline for flowing the formation fluids capable of isolating a quantity of the formation fluids in a portion thereof; and a pump unit for depressurizing the isolated formation fluids; and a measurement controller which controls the downhole tool. The measurement controller includes a rough value estimation unit which estimates a rough value of the bubble point pressure of the formation fluids; and a speed controller which controls the depressurizing speed of the pump unit such that the isolated formation fluids are depressurized at a first speed to a certain pressure which is a predetermined value higher than said estimated rough value, and the isolated fluids are depressurized at a second speed which is slower than said first speed in order to measure a precise value of the bubble point pressure.

Abstract: Methods and systems for determining reservoir parameters of subterranean formations. A tool is configured or designed for deployment at at least one depth in a borehole traversing a subterranean formation. The tool comprises at least one sensor configured or designed for sensing rotational components of a seismic wavefield deployed in an array comprising at least one sensor configured or designed for sensing translational components of a seismic wavefield. A computer is in communication with the tool and a set of instructions executable by the computer that, when executed, process the seismic measurements and derive parameters relating to the formation based on the seismic measurements.

Abstract: Methods for compression of sonic log data include STC processing, sorting peak components in the sonic data; filtering the sorted peak components to remove high-frequency portions in the peak components; and decimating the filtered peak components according to a selected ratio to produce compressed data. One method for telemetry transmission of downhole sonic log data includes sorting peak components in the sonic log data; compressing the sorted peak components to produce compressed data; packing the compressed data to produce data packets for telemetry transmission; and sending the data packets using telemetry.

Abstract: An interchangeable sleeve for a downhole tool includes a substantially cylindrical body configured to circumferentially engage the downhole tool, a blade extending radially from the body, and a transducer disposed within the blade. A drilling assembly includes a drill collar, an interchangeable blade configured to couple to the drill collar, and a transducer disposed within the blade. A size of the blade and a size of the transducer are selected based on a diameter of a borehole in which the downhole tool is to be used. A method of manufacturing an interchangeable sleeve for a downhole tool includes forming a blade on a body of the sleeve such that the blade extends radially from the body, disposing a transducer within the blade, and configuring the sleeve to circumferentially engage the downhole tool.

Abstract: Methods and systems for borehole telemetry utilizing a tool configured or designed for deployment in a borehole traversing a subterranean formation. The tool includes a downhole telemetry module; a surface telemetry module; and a datalink between the downhole and surface modules configured or designed for transferring data over two or more data communication channels, wherein the transferred data comprises coding at a transmitter to increase the signal to noise ratio (SNR) of the data.

Abstract: A sensor apparatus comprising a housing, two or three gyroscope units and three accelerometer units. The gyroscope units are oriented orthogonally respective to each other and mounted within the housing. Each gyroscope unit includes a plurality of gyroscopes with input axes parallel to each other. The accelerometer units are oriented orthogonally respective to each other and mounted within the housing. Each accelerometer unit includes a plurality of accelerometers with detection axes parallel to each other.

Abstract: A method and system for determining dynamic permeability of gas hydrate formations including deploying a tool within a wellhole configured for magnetic resonance measurements, determining permeability of a formation at or near zero saturation of the gas hydrate and deriving the relationship between permeability and gas hydrate saturation for the formation.

Abstract: Methods and apparatus to optically determine velocities of downhole fluids are disclosed. Some example methods to determine a velocity of a downhole fluid include exciting a fluorescent substance in a downhole fluid with an optical signal via an optical interface. The example methods further include detecting fluorescence of the downhole fluid via an optical fiber at a predetermined distance from the optical interface, and determining the velocity of the downhole fluid based on the detected fluorescence.

Abstract: Remote sensing systems are provided including a recorder, a cable network and a plurality of downhole sensor nodes. The cable network comprises a first cable and a second cable. The first and second cables form a loop. The recorder and the plurality of downhole sensor nodes are connected to the cable network in series. The first cable delivers power to the nodes and the second cable comprises a power return and closes the loop to the recorder.

Abstract: Vibrating wire viscometers are disclosed. An example apparatus to determine the viscosity of a downhole fluid is described, the apparatus including a wire to be immersed in a downhole fluid, to vibrate when an alternating current is applied to the wire within a magnetic field, and to generate an electromotive force when vibrating within the magnetic field, the wire comprising a first resistance. The apparatus further includes a nulling circuit coupled to the wire, wherein the nulling circuit comprises a second resistance that is selectable to be substantially equal to the first resistance, and an analyzer coupled to the wire and the nulling circuit to determine the first resistance, the second resistance, and a viscosity of the downhole fluid based on the first and second resistances, at least one characteristic of the wire, and the electromotive force.

Abstract: Methods and apparatus to evaluate subterranean formations are described. An example method of evaluating a subterranean formation includes, obtaining a first sample from a first wellbore location. Additionally, the example method includes obtaining a second sample from a second wellbore location different than the first wellbore location. Further, the example method includes mixing the first sample with the second sample in a flowline to obtain a substantially homogenous mixture. Further still, the example method includes measuring a parameter of the mixture to evaluate the subterranean formation.