Method and structure for incorporating fiber optic acoustic sensors in a seismic array

摘要

A structure for incorporating fiber optic acoustic sensor in a seismic array includes means for supporting the sensor in a spiral around a central strength member in a manner to isolate shear waves from the sensor. In another aspect, an axially oriented sensor in a seismic array comprises a pressure sensitive optical fiber wound in a spiral around the axis, the fiber having a plurality of optical Bragg gratings and a plurality of channels. The preferred structure may include four tubes spiraling around the strength member. One of the tubes encloses an optical fiber sensor which is maintained in an extended orientation by fluid flow through the tube. Another of the tubes serves as a return path for fluid through the sensor tube. The other tubes enclose high speed and low speed data conductors, respectively. The sensor fiber may also be wound in a spiral around a compliant core in a manner to satisfy Poisson's Ratio such that strain on the compliant core does not alter the tension of the sensor fiber.