Abstract: In general, in one aspect, embodiments relate to a method, that includes lowering a tool string down into a wellbore extending into a subterranean formation, where the tool string includes perforating charges, and one or more acoustic emitters, energizing the one or more acoustic emitters to form at least an acoustic signal while the tool string is being drawn up-hole, detecting the acoustic signal with a sensing cable disposed within the wellbore, determining an angular orientation of the tool string relative to the sensing cable based at least in part on the acoustic signal, and detonating at least one of the perforating charges when its firing direction is not directed at the one or more sensing cables.

Abstract: An illustrative distributed sensing system includes a fiberoptic cable, a transmitter module, and a receiver module. The transmitter module is coupled to the fiberoptic cable to communicate light in each of multiple independent paths to each of multiple positions along the cable, The receiver module is coupled to the fiberoptic cable to receive backscattered light from said multiple positions along the cable via the multiple independent paths. The receiver module includes at least one receiver for each of said multiple independent paths to obtain simultaneous measurements for each of said multiple positions. The multiple independent paths may be provided by wave division multiplexing, frequency division multiplexing, spatial mode division multiplexing, multicore fiber, and/or multiple fibers.

Abstract: An illustrative distributed sensing system includes a fiberoptic cable, a transmitter module, and a receiver module. The transmitter module is coupled to the fiberoptic cable to communicate light in each of multiple independent paths to each of multiple positions along the cable, The receiver module is coupled to the fiberoptic cable to receive backscattered light from said multiple positions along the cable via the multiple independent paths. The receiver module includes at least one receiver for each of said multiple independent paths to obtain simultaneous measurements for each of said multiple positions. The multiple independent paths may be provided by wave division multiplexing, frequency division multiplexing, spatial mode division multiplexing, multicore fiber, and/or multiple fibers.

Abstract: A system for synchronizing an optical signal with an initiation of an event can include an event controller which controls the initiation of the event, and an optical modulator which modulates the optical signal in response to receipt of an indication from the event controller that the event is initiated. A method of synchronizing an optical signal with an initiation of an event can include transmitting from an event controller an indication that the event is initiated, receiving the indication that the event is initiated, and modulating the optical signal in response to the receiving. A system for synchronizing multiple optical signals can include at least one time-code generator which generates time-codes, and multiple optical modulators which modulate the respective optical signals in response to generation of the time-codes by the at least one time-code generator.