A method for logging a wellbore includes positioning a downhole tool having a downhole clock in the wellbore, logging the wellbore with the downhole tool, transmitting a surface signal from a wellbore surface to the downhole tool, and receiving the surface signal at the downhole tool. The method also includes transmitting a downhole signal from the downhole tool to the surface, receiving the downhole signal at the wellbore surface, and determining clock drift based on an arrival time of the surface signal at the downhole tool and an arrival time of the downhole signal at the wellbore surface.

A master data acquisitions system is provided. A trigger emits a sync signal to be sensed by each of a plurality of data acquisition systems. A controller is communicatively coupled with each of the plurality of data acquisition systems. The controller receives data from each of the data acquisition systems. The data for each of the plurality of data acquisition systems include the sensed sync signal. The controller synchronizes the data from each of the plurality of data acquisition systems by aligning the sensed sync signal for each of the plurality of data acquisition systems.

A sensor package may include a sensor housing unit and a first sensor that may acquire a first set of measurements within a first measurement range. The sensor package may also include a second sensor configured to acquire a second set of measurements within a second measurement range. The first measurement range and the second measurement range may include an overlapping range used to calibrate the first set of measurements, the second set of measurements, or both.

A system that is positionable in a wellbore can include a transceiver that is positionable external to a casing string. The transceiver can be remotely programmable while in the wellbore to set an internal clock using a timing signal wirelessly transmitted from a source and a position of the transceiver in the wellbore relative to the source. The transceiver can use the internal clock for controlling a timing of the transceiver for transmitting a wireless signal.

A method and apparatus may include activating, by a network node, power of a global-positioning-system receiver or power of an active antenna of the global-positioning-system receiver. The apparatus uses the global-positioning-system receiver to perform synchronization of the apparatus. The method may include receiving at least one measurement, wherein the at least one measurement comprises real-time, predictive, or historic data. The method may also include determining a holdover duration based on the at least one measurement. The holdover duration corresponds to a length of time where the power of the global-positioning-system receiver or the power of the active antenna is to be turned off. The method may also include deactivating the power of the global-positioning-system receiver or the power of the active antenna for the holdover duration.

A method for calibrating a downhole tool may comprise disposing a downhole tool in a borehole, transmitting a signal from a master module disposed on the first device to a module disposed on the second device, transmitting a return signal from the module to the master module, receiving the return signal with the master module, measuring a tone enabled delay for the signal to travel from the master module to the module, and determining a time delay of a return signal to travel from the module to the master module. A well measurement system may comprise a downhole tool. The downhole tool may further comprise a first device and a master module disposed on the first device, wherein the master module may comprise a master transmitter and a master receiver. In examples, the downhole tool may further comprise a second device and a module disposed on the second device.

A wireless seismic data acquisition unit with a wireless receiver providing access to a common remote time reference shared by wireless seismic data acquisition units in a seismic system. The receiver can replicate local version of remote time epoch to which a seismic sensor analog-to-digital converter is synchronized. The receiver can replicate local version of remote common time reference to time stamp local node events. The receiver can be placed in a low power, non-operational state over periods of time during which the unit continues to record seismic data, thus conserving unit battery power. The system corrects the local time clock based on intermittent access to the common remote time reference. The system corrects the local time clock via a voltage controlled oscillator to account for environmentally induced timing errors.

A method of correcting clock drift in at least one slave clock in a seismic node. The method comprises obtaining a number of clock drift measurements of the at least one slave clock in the at least one seismic node. A clock drift correction function as a function of time is calculated by curve fitting the number of clock drift measurements to a 2nd order polynomial. A time of reference of the recorded seismic sensor data is corrected by the 2nd order polynomial clock drift correction function.

A timing alignment method for data acquired by monitoring units of a borehole-surface micro-seismic monitoring system includes acquiring two rock-burst waveform data segments with GPS timestamps; calculating a time difference and a number of sampling points between each pair of adjacent GPS timestamps; adding, on an equal-interval basis, a sampling time to a sampling point missing a timestamp between each pair of adjacent GPS timestamps; calculating average sampling frequencies of the two rock-burst waveform data segments, adding, on an equal-interval basis, a sampling time to a sampling point missing a timestamp except first and last GPS timestamps in each of the two data segments; obtaining sampling times of all sampling points, resampling the sampling times according to a uniform sampling frequency; calculating a rock-burst waveform data segment at a new sampling time with a linear interpolation formula, and aligning the sampling times of the two rock-burst waveform data segments.

There is disclosed a method and system for controlling network timing precision of a seismic collector, and a terminal device. The method includes: using an interrupt mode to transmit a data packet; calculating an optimal network delay; and correcting a transmission error in a network timing process according to the optimal network delay, after which the physical layer of a server receives the data packet and sends the data from the physical layer of the server to the application layer of the server using the interrupt mode thereby timing the data packet.