Abstract: An electromagnetic telemetry system may include an electrically conductive member, a transmitter coupled to the electrically conductive member, the transmitter configured to induce an alternating current along the electrically conductive member, the alternating current representing encoded information, a first receiver coupled to the electrically conductive member, the first receiver configured to receive electromagnetic waves resulting from the alternating current, a second receiver positioned at a location apart from the first receiver, the second receiver configured to receive the electromagnetic waves resulting from the alternating current, and a receiver processing system communicatively coupled to the first receiver and the second receiver, the receiver processing system configured to process the electromagnetic waves received by the first receiver and the second receiver into a combined signal, and decode the combined signal.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate to acquire a first signal from a first magnetometer at least partially disposed within a Helmholtz coil, to acquire a second signal from a second magnetometer having a sensitivity at least one thousand times less than the first magnetometer, to process the second signal to determine a drive signal, to drive the Helmholtz coil using the drive signal so as to null an ambient Earth magnetic field surrounding the first magnetometer, and to process the first signal as one of a down hole location signal or a down hole telemetry signal, the location signal to determine a range to a sub-surface object, and the telemetry signal to provide data from down hole drilling operations. Additional apparatus, systems, and methods are disclosed.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate to receive a derived clock signal downhole, the derived clock signal being derived from a surface clock signal (associated with a surface clock), such that the frequency of the derived clock signal is less than the frequency of the surface clock signal. Further activity may include measuring the frequency of the derived clock signal in terms of an uncorrected downhole clock frequency (associated with a downhole clock) to provide a measured frequency equivalent, and correcting time measurements made using the downhole clock, based on the measured frequency equivalent, or based on an actual frequency of the downhole clock determined according to the measured frequency equivalent. Additional apparatus, systems, and methods are described.

Abstract: A disclosed downhole telemetry system employs an array of near-field electromagnetic communication devices to relay information along a tubular in a borehole. In some embodiments, the devices are permanently attached to pipe joints without requiring any structural modification of the pipe joints. As the pipe joints are strung together in the normal fashion to form a tubular, the devices automatically establish a wireless communications path between an uphole terminus device and any downhole sensors or tools. The devices can include built-in sensors to provide distributed sensing of parameters such as temperature and pressure. In some embodiments the device array incorporates redundancy to minimize the chance of a communications network failure. The device array has applications for logging-while-drilling, production testing, well completion, reservoir monitoring, and well control.

Abstract: An example system for transmitting signals may include a signal source, a signal target, and a transmission cable coupled to the signal source and the signal target. The transmission cable may include a first conductor and a second conductor surrounding the first conductor. A resistive layer may be between the first conductor and the second conductor and allow current flow between the first conductor and the second conductor.

Abstract: A system having a downhole sensor device and a compression device to obtain a sparse representation of data in downhole telemetry applications is described. The downhole sensor device can collect sensor data while the downhole sensor device is within a borehole. The compression device is coupled to the downhole sensor device and configured to receive the sensor data. The compression device can determine a wavelet coefficient vector for at least one row of n-tuple vectors. The wavelet coefficient vector can have a sparse representation of one or more nonzero elements. The compression device can process the wavelet coefficient vector through a set of compression algorithms, and determine a minimal bit cost of the processed wavelet coefficient vector. The compression device can select a compression algorithm from the set of compression algorithms corresponding to the minimal bit cost. The compression device can generate compressed data based on the selected compression algorithm.

Abstract: An antenna assembly includes a bobbin that provides a cylindrical body that defines an outer radial surface, an inner radial surface, and a central axis. One or more channels are defined on the outer radial surface, and each channel provides a first sidewall, a second sidewall opposite the first sidewall, a floor, and a pocket jointly defined by the first sidewall and the floor. A coil including one or more wires is wrapped about the bobbin and received within the one or more channels.

Abstract: Apparatus, systems, and methods may operate to receive radiated energy as scattered energy after the radiated energy interacts with a geologic formation, wherein the scattered energy is received at a sub-surface multi-channel sensor array that operates to transform the scattered energy into received signals, and wherein the radiated energy is provided by a sub-surface source of elastic energy; and to identify discontinuous features in the geologic formation by interferometric comparison of the received signals as elastic signals and/or electromagnetic signals among some sensors in the sensor array, or by time-reversal propagation of the received signals as elastic and/or electromagnetic signals in a numeric model of a volume of the geologic formation. Additional apparatus, systems, and methods are disclosed.

Abstract: The present disclosure relates to a composite fluid including an electrically insulating foundation fluid having a dielectric constant and a dielectric strength, and an additive combined with the foundation fluid that results in a composite fluid having a dielectric constant and a dielectric strength greater than the dielectric constant and the dielectric strength of the foundation fluid.

Abstract: Video of an above ground effect of a subterranean event is received. The subterranean event is identified using Eulerian video magnification of the received video.

Abstract: The present disclosure relates to a composite fluid including a foundation fluid having an impedance at a frequency, and an additive combined with the foundation fluid that results in a composite fluid having an impedance different than the impedance of the foundation fluid at the frequency.

Abstract: Video of an effect on equipment of an event is received. The event is identified using Eulerian video magnification of the received video.

Abstract: Borehole data presentation systems and methods that facilitate communication of volumetric logging data to a surface processing system for presentation to a driller or other user interested in visualizing the formations surrounding a borehole. The disclosed systems optionally tailor the telemetry stream to match the chosen display technique, thereby maximizing the logging system utility for the driller. Variable opacity of certain data regions or certain data discontinuities greatly facilitates data comprehension, particularly when true three-dimensional display technologies are employed. Holographic or stereoscopic display technologies may be employed to show the three-dimensional dependence of measured formation properties such as resistivity, density, and porosity. Alternatively, the radial axis can be used to represent a formation parameter value, thereby enabling cylindrical cross-plots of multiple measurements.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate control the operation of a fluid pulse source using drilling fluid to excite vibrations in a shock sub, increasing the axial vibration in a drill string to reduce static friction between the drill string and a formation surrounding the drill string. The vibrations are excited at a fundamental frequency that is outside of the operational communications frequency range of an associated acoustic telemetry communications system. Additional apparatus, systems, and methods are disclosed.

Abstract: An example method for distributed sensing in a subterranean formation may include drilling to a first depth in the subterranean formation using a drilling device and detaching a first phase of the drilling device at the first depth. The first phase may include a first coil of line and a first sensor. The drilling assembly may drill to a second depth and decouple a second phase of the drilling device, with the second phase including a second coil of line and a second sensor. Measurements may be generated at the first and second depths using the first and second sensors, respectively.

Abstract: An improved system and method for ranging while drilling, in effect, induces a dynamic hot spot on the casing of a nearby well. The induced hot spot acts as a magnetic source that can be reliably detected from within the drillstring and in such a manner as to infer the relative position and orientation of the casing to the drillstring. At least some disclosed method embodiments employ one or more rotating magnets in the drillstring, an array of at least two magnetometers in the drillstring and one or more phase-locked loops that are used to enhance the signal to noise ratio of the magnetic signal scattered off of the casing from the rotating magnetic field. The rotating magnet or magnets may be magnetic dipoles or magnetic multipoles, and may be modulated to enable the use of multiple magnetic field sources.

Abstract: Procedures are described for monitoring dynamics along a drill string during the drilling process using only surface instrumentation or using a combination of surface and downhole instrumentation. Events such as drill collar whirl may be identified from signatures found in signals generated by an electromagnetic sensor such as a magnetometer and/or from a mechanical sensor such as accelerometer. Additional embodiments are described.

Abstract: An example method for distributed sensing in a subterranean formation may include drilling to a first depth in the subterranean formation using a drilling device and detaching a first phase of the drilling device at the first depth. The first phase may include a first coil of line and a first sensor. The drilling assembly may drill to a second depth and decouple a second phase of the drilling device, with the second phase including a second coil of line and a second sensor. Measurements may be generated at the first and second depths using the first and second sensors, respectively.

Abstract: A disclosed method includes measuring properties of a formation with a logging tool disposed in a borehole. The method also includes acquiring measurement data corresponding to the measured properties of the formation. The method also includes adjusting a control parameter for logging operations of the logging tool based on at least some of the measurement data and an adaptive learning engine within the logging tool.

Abstract: An example system for transmitting signals may include a signal source, a signal target, and a transmission cable coupled to the signal source and the signal target. The transmission cable may include a first conductor and a second conductor surrounding the first conductor. A resistive layer may be between the first conductor and the second conductor and allow current flow between the first conductor and the second conductor.