Systems and methods for formation characterization in a subterranean formation are disclosed. A set of microelectromechanical system (MEMS) devices may be disposed in a circulating fluid. Each MEMS device in the set may have a machine-scannable designator. A MEMS scanner may be configured to scan the designator of a MEMS device in response to circulation of the circulating fluid in a wellbore surrounded by the formation. A MEMS analysis subsystem communicatively coupled with the MEMS scanner may store the designator of each MEMS device in the set, detect a subset of MEMS devices by receiving the designators of MEMS devices from the MEMS scanner, and determine a characteristic of the formation based on the subset of MEMS devices.

A running tool for deploying a tubular string into a wellbore and methods for operating a wellbrore using the running tool are disclosed. The running tool includes a tubular body and a latch for releasably connecting the tubular string to the body. The running tool further includes a lock to keep the latch engaged.

A telemetry apparatus for use in a well can include multiple segments, the segments comprising at least one buoyancy control device, at least one telemetry device, and at least one articulation device that controls a relative orientation between adjacent ones of the segments. A method of communicating in a subterranean well can include installing at least one telemetry apparatus in the well, the telemetry apparatus comprising a telemetry device and a buoyancy control device, and the telemetry device communicating with another telemetry device at a remote location. A well system can include at least one telemetry apparatus disposed in a wellbore, the telemetry apparatus comprising multiple segments, the segments including at least one buoyancy control device and at least one telemetry device.

Provided here are methods and system to detect an untethered device in a wellhead. The untethered device includes a housing, a transducer, and one or more sensors configured to measure data along the subterranean well. The transducer emits acoustic signals that are received by microphones on the surface of the wellhead. Based on these acoustic signals, the location of the untethered device is determined and appropriate valves may be opened or closed by an operator.

An example downhole motor may include a first housing and a second housing with first and second portions characterized by non-parallel longitudinal axes. The second housing may be rotatably coupled to the first housing, and the first portion of the second housing may be arranged in a fixed, non-parallel longitudinal orientation with the first housing. A drive shaft may be at least partially within the first housing, and the motor may further comprise a selectively engageable torque coupling between the drive shaft and the second housing, positioned within the first housing.

A deployment assembly for expanding a liner string in a wellbore includes: a tubular mandrel having a bore therethrough; an expander linked to the mandrel and operable between an extended position and a retracted position; an extension tool disposed along the mandrel and operable to extend the expander; and a retraction tool disposed along the mandrel. The retraction tool has: an upper piston in fluid communication with the mandrel bore and operable to retract the expander; a lower piston in fluid communication with the mandrel bore and operable to balance the upper piston; a valve disposed between the pistons for isolating the lower piston from the upper piston in a closed position; and an electronics package linked to the valve for opening and closing the valve in response to receiving a command signal.

An untethered sensing object able to sense and record well fluid and wellbore parameters. The untethered sensing object is adapted to perform, in addition, a well fluid isolation with a plugging element previously placed inside the wellbore.

A bottom hole assembly for use in a subterranean well can include a whipstock, a mill releasably secured to the whipstock, an antenna, and a release mechanism configured to release the mill from the whipstock in response to a predetermined radio frequency signal received by the antenna. A method can include positioning a bottom hole assembly in a well, the bottom hole assembly including a mill and a whipstock releasably secured to the mill, and then releasing the mill from the whipstock by displacing a radio frequency identification tag into the bottom hole assembly. A well system can include a bottom hole assembly comprising an anchor, a whipstock and a mill, and a radio frequency identification tag displaceable with fluid flow into the bottom hole assembly.

Systems and methods for formation characterization in a subterranean formation are disclosed. A set of microelectromechanical system (MEMS) devices may be disposed in a circulating fluid. Each MEMS device in the set may have a machine-scannable designator. A MEMS scanner may be configured to scan the designator of a MEMS device in response to circulation of the circulating fluid in a wellbore surrounded by the formation. A MEMS analysis subsystem communicatively coupled with the MEMS scanner may store the designator of each MEMS device in the set, detect a subset of MEMS device by receiving the designators of MEMS devices from the MEMS scanner, and determine a characteristic of the formation based on the subset of MEMS devices.

A downhole injector apparatus for injecting a taggant into a wellbore includes an injector nozzle outlet and a taggant reservoir in fluid communication with the injector nozzle outlet and configured to hold the taggant to be injected. The apparatus further includes a pressure wave generator configured to apply a pressure wave within the reservoir to expel the taggant from the reservoir through the injector nozzle outlet.