Abstract: A fracture mapping system for use in hydraulic fracturing operations utilizing non-directionally sensitive fiber optic cable, based on distributed acoustic sensing, deployed in an observation well to detect microseismic events and to determine microseismic event locations in 3D space during the hydraulic fracturing operation. The system may include a weighted probability density function to improve the resolution of the microseismic event on the fiber optic cable.

Abstract: A method for determining microseismic events. The method may include measuring a seismic travel time of a microseismic event with a fiber optic line disposed in a first wellbore, forming a probability density function for the microseismic event based at least in part on the seismic travel time measurement, modifying the probability density function by applying one or more constraints to form a modified probability density function, identifying one or more most probable source locations from the modified probability density function, and forming a microseismic event cloud from the one or more most probable source locations.

Abstract: A fiber optic cable positioned along a casing string in a wellbore may be calibrated by exciting a tube wave in the wellbore and detecting, by the fiber optic cable, a reflected tube wave. The reflected tube wave may correspond to a reflection of the tube wave off an obstacle within the wellbore. The obstacle may have a known location such that a reference point along the fiber optic cable may be associated with the known location of the obstacle for calibrating the fiber optic cable. Downhole applications utilizing data collected by the calibrated fiber optic cable, including location data, may weight the data collected based at least in part on an uncertainty value associated with a particular calibrated location along the length of the fiber optic cable.

Abstract: A well system includes a fiber optic cable positionable downhole along a length of a wellbore. The well system also includes a reflectometer communicatively coupleable to the fiber optic cable. The reflectometer injects optical signals into the fiber optic cable and receives reflected optical signals from the fiber optic cable. Further, the reflectometer identifies strain detected in the reflected optical signals generated from seismic waves of a microseismic event. Additionally, the reflectometer identifies a focal mechanism of the microseismic event and velocities of the seismic waves. The reflectometer also determines a position of the microseismic event using the strain detected in the reflected optical signals, the focal mechanism of the microseismic event, and the velocities of the seismic waves.

Abstract: A well system includes a fiber optic cable positionable downhole along a length of a wellbore and a reflectometer communicatively coupleable to the fiber optic cable. The reflectometer detects and locates a microseismic event using strain detected in reflected optical signals received from the fiber optic cable. Further, the reflectometer computes a set of spectra for waveforms of the microseismic event. Additionally, the reflectometer aggregates each spectrum from the set of spectra that meet an acceptance threshold to generate an aggregate spectrum. Furthermore, the reflectometer applies a fault source model to the aggregate spectrum to determine a magnitude of the microseismic event.

Abstract: A fracture mapping system for use in hydraulic fracturing operations utilizing non-directionally sensitive fiber optic cable, based on distributed acoustic sensing, deployed in an observation well to detect microseismic events and to determine microseismic event locations in 3D space during the hydraulic fracturing operation. The system may include a weighted probability density function to improve the resolution of the microseismic event on the fiber optic cable.

Abstract: A fiber optic cable positioned along a casing string in a wellbore may be calibrated by exciting a tube wave in the wellbore and detecting, by the fiber optic cable, a reflected tube wave. The reflected tube wave may correspond to a reflection of the tube wave off an obstacle within the wellbore. The obstacle may have a known location such that a reference point along the fiber optic cable may be associated with the known location of the obstacle for calibrating the fiber optic cable. Downhole applications utilizing data collected by the calibrated fiber optic cable, including location data, may weight the data collected based at least in part on an uncertainty value associated with a particular calibrated location along the length of the fiber optic cable.

Abstract: A well system includes a fiber optic cable positionable downhole along a length of a wellbore and a reflectometer communicatively coupleable to the fiber optic cable. The reflectometer detects and locates a microseismic event using strain detected in reflected optical signals received from the fiber optic cable. Further, the reflectometer computes a set of spectra for waveforms of the microseismic event. Additionally, the reflectometer aggregates each spectrum from the set of spectra that meet an acceptance threshold to generate an aggregate spectrum. Furthermore, the reflectometer applies a fault source model to the aggregate spectrum to determine a magnitude of the microseismic event.

Abstract: A well system includes a fiber optic cable positionable downhole along a length of a wellbore. The well system also includes a reflectometer communicatively coupleable to the fiber optic cable. The reflectometer injects optical signals into the fiber optic cable and receives reflected optical signals from the fiber optic cable. Further, the reflectometer identifies strain detected in the reflected optical signals generated from seismic waves of a microseismic event. Additionally, the reflectometer identifies a focal mechanism of the microseismic event and velocities of the seismic waves. The reflectometer also determines a position of the microseismic event using the strain detected in the reflected optical signals, the focal mechanism of the microseismic event, and the velocities of the seismic waves.