Downhole telemetry systems and related methods adaptively compensate for channel non-linearity effects. To compensate for channel non-linearity, the optimum signal generation parameters are determined that produce the desired modulated pressure variation at the surface. The signal generation parameters are optimized to minimize the discrepancy between the surface detected pressure signal and the intended signal. The mud propagation channel is first estimated in light of the known modulation scheme under an ideal linear-time-invariant channel assumption. The estimated channel is used to synthesize the modulated pressure signal undergoing the mud propagation given the initial signal generation parameters. The method then varies the synthesized signal generation parameters to search for the optimal signal generation parameters. The optimal signal generation parameters are then sent over downlink channel to the downhole pulser, which is ultimately used to generate the pulse waveform.

A system can flush a drilling fluid sample with a hydrocarbon blend, which includes a determined concentration of at least one chemical species to generate a flushed drilling fluid sample. The system can extract a dissolved gas from the flushed drilling fluid sample. The system can determine a concentration over time of at least one chemical species of the dissolved gas. The system can generate an area per concentration curve based on the concentration over time of the at least one chemical species. The system can determine at least one concentration value of the at least one chemical species. The system can modify the at least one concentration value based on the area per concentration curve. The system can then correct bias caused by the gas extractor and fluid sampling system.

A frac plug includes a body having an outer surface, a first pocket in the outer surface, and a second pocket in the outer surface. In addition, the frac plug includes a first sensor removably disposed in the first pocket. The first sensor is configured to measure and record a plurality of pressures. The frac plug also includes a second sensor removably disposed in the second pocket. The second sensor is configured to measure and record a plurality of pressures. Further, the frac plug includes a first cap releasably coupled to the body and closing the first pocket. Moreover, the frac plug includes a second cap releasably coupled to the body and closing the second pocket. The first cap includes a port and the second cap includes a port.

A downhole tool includes a body configured to move in a wellbore formed from a terranean surface to a subterranean formation in a direction downhole of the terranean surface independent of a downhole conveyance attached to the body; one or more sensors positioned in the body, the one or more sensors configured to measure a value associated with at least one of the wellbore or the terranean surface; and at least one mass positioned in the body and configured to adjust an orientation of the body in response to one or more forces acting on the body as the downhole tool moves in the wellbore in the direction downhole of the terranean surface.

Downhole equipment and surface equipment communicate wirelessly with each other. A signal wirelessly transmitted at a first frequency from a downhole controller disposed within a wellbore is received at a surface location. The received signal is demodulated to a demodulated digital value. The demodulated value is added to an end of a buffer string. The buffer string is processed to determine whether the buffer string contains a message that is valid. In response to determining that the buffer string contains the message that is valid, the message is decoded. A command signal is wirelessly transmitted at a second frequency different from the first frequency to the downhole controller to adjust a state of the downhole controller.

Systems and methods for communicating between surface equipment and a downhole tool installed in a well. First and second toroidal transformers are positioned around an inner one of a pair of coaxial structural members of a well completion (e.g., a pump rod and tubular, or a tubular and a well casing) which are electrically coupled to form an electrical circuit. A transmitter generates a data signal which is applied to the first toroidal transformer, causing a corresponding electrical current to be induced in the circuit, which then induces the data signal on the second toroidal transformer. A receiver coupled to the second toroidal transformer receives the data signal induced on the second toroidal transformer. The transmitter and receiver may be components of transceivers that may communicate bidirectionally. Additional toroidal coils and transceiver may be provided to communicate with equipment at additional locations in the well.

In described examples, there are methods and systems for communicating data signals in wells. The methods and systems may facilitate communication of data signals, for example, from an open-hole section of a well, or in a well having a discontinuous metallic well structure.

Systems and methods for instructing a device within a wellbore of a subterranean well includes a drill string with an actuator assembly extending into the subterranean. The actuator assembly has a first pipe member with a segment formed of a first material. A second pipe member is coaxially aligned with the first pipe member. A plurality of bearings are positioned between the first pipe member and the second pipe member. Each of the plurality of bearings includes a second material. The first material is reactive to the second material. Certain of the plurality of bearings are changeable bearings that include a dissolvable material. The actuator assembly is operable to instruct an operation of the device by generating an instruction signal by rotating the first pipe member relative to the second pipe member and interpreting a pattern of a reaction of the segment as a bearing rotates past the segment.

Provided is a downhole perforating device, a well system, and a method for perforating a well system. The downhole perforating device, in one aspect, includes a perforating structure for surrounding at least a portion of an outer surface of a wellbore casing. The downhole perforating device, according to this aspect, includes one or more perforation elements at least partially embodied within the perforating structure, the one or more perforation elements positioned to perforate the wellbore casing to an inside thereof, and electronics at least partially embodied within the perforating structure, the electronics for triggering the one or more perforation elements.

Wellbore plugs that include an interrogation device, hydrocarbon wells that include the wellbore plugs, and methods of operating the hydrocarbon wells are disclosed herein. The wellbore plugs include a plug body, an interrogation device, and a sealing structure. The interrogation device is contained within the plug body and includes a sensor configured to detect at least one parameter of the hydrocarbon well. The hydrocarbon wells include a wellbore, a downhole tubular, the plug, and a communication device configured to receive communication data from the interrogation device. The methods include releasing an interrogation device from a plug, detecting at least one parameter within the hydrocarbon well with the interrogation device, transmitting communication data from the interrogation device, and receiving the communication data with a communication device.