Embodiments provide an expandable meshed component for guiding an untethered measurement device used in a subterranean well. The expandable meshed component includes an uphole radial portion, an intermediate radial portion, a downhole radial portion, an outer meshed wall, and an inner meshed wall. The expandable meshed component has a density less than a fluidic component occupying the space. A method for guiding an untethered measurement device used in a subterranean well includes deploying a compressed expandable meshed component tethered to the untethered measurement device, disconnecting the compressed expandable meshed component and the untethered measurement device, and releasing a sleeve surrounding the compressed expandable meshed component such that the expandable meshed component expands, ascends, and fits into an annulus.

A system that is positionable in a wellbore in a subterranean formation can include a first transceiver that is positionable external to a casing string in the wellbore. The first transceiver can wirelessly transmit data via a signal within a frequency band that is selected based on a fluid property of a fluid in the wellbore and a property of the subterranean formation. The system can also include a second transceiver that is positionable externally

A communication system that is positionable in a wellbore can include a first transceiver positioned externally to a casing string. The first transceiver can be operable to detect a presence or an absence of a surface wave; determine a location of a fluid in the wellbore based on the presence or the absence of the surface wave; and transmit data indicative of the location to a second transceiver. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is non-transverse to a direction of propagation of the surface wave. The communication system can also include the second transceiver, which can be positioned externally the casing string and operable to receive the data.

A system that is positionable in a wellbore can include a chain of transceivers that are positionable external to a casing string. Each transceiver in the chain of transceivers can be operable to transmit a wireless signal using a separate frequency guard band that is assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers.

A communication system that is positionable in a wellbore can include a first transceiver for coupling externally to a casing string. The first transceiver can be for wirelessly transmitting data by generating and modulating a surface wave that propagates along an interface surface. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is at an acute angle to a direction of propagation of the surface wave. The communication system can also include a second transceiver for coupling to the casing string and for wirelessly receiving the surface wave and detecting the data.

A system for use in a wellbore can include a first transceiver that is operable to transmit a wireless signal. The first transceiver can be positioned in an electrically isolated chamber between a tubular and a casing string for confining a transmission of the wireless signal to within the electrically isolated chamber. The system can also include a second transceiver that is positionable in the electrically isolated chamber for receiving the wireless signal from the first transceiver.

Embodiments of a downhole drilling assembly generally include a rotatable lower drilling assembly, a rotatable upper drilling assembly, and a drill bit, wherein the upper drilling assembly contains a mud motor adapted for clockwise rotation of its stator and counter-clockwise rotation of its rotor, whereby the lower drilling assembly is rotatable in the opposite direction of the upper drilling assembly or maintainable in a non-rotating state. The apparatus further includes sensors adapted to continuously measure physical properties and/or drilling parameters and a mechanism for continuously transmitting information relating thereto to the surface.

Embodiments of a method for operating a downhole drilling assembly generally include continuously measuring physical properties and/or drilling parameters proximate the drill bit, continuously transmitting information relating thereto to the surface, and controlling rotation of a lower drilling assembly in a non-rotating state or in the opposite direction of an upper drilling assembly by varying drill string rotation.

A downhole sensing system includes a casing connector configured to fluidly couple segments of a downhole conduit through which a fluid flows. The downhole sensing system includes a sensing device disposed in the casing connector and configured to measure one or more parameters. The downhole sensing system also includes a wireless communication device disposed in the casing connector and configured to wirelessly communicate one or more parameters.

Apparatus, systems, and methods may operate to transmit a data signal along a transmission line extending lengthwise along a drill string, the transmission line comprising an outer conductive path provided by a tubular wall of a drill pipe that extends along the drill string; and an internal conductive path extending along an interior passage that is bounded by a radially inner cylindrical surface of the drill pipe and along which drilling fluid is conveyed, the inner conductive path being substantially insulated from the outer conductive path. Additional apparatus, systems, and methods are described.

A system includes a transmitter for use in conjunction with a horizontal directional drilling system that transmits a multi-bit symbol stream that characterizes sensor symbols for receipt by an aboveground portable device. The portable device receives the symbol stream for aboveground recovery of the sensor signals. The transmitter can precisely place the symbol frequencies at least to avoid a noise environment, as well as to avoid powerline harmonics, and can utilize wave shaping for transmitted symbols at least to provide for transmission power control, spectral content control and wideband antenna matching. The receiver can measure the noise environment to identify the symbol frequencies used by the transmitter. The noise can be scanned at an incremental resolution across a wide frequency bandwidth for display or automatic symbol frequency selection.