Downhole Acoustic Wave Sensing with Optical Fiber

摘要

A technique facilitates geophysical exploration by employing a tool wrapped with an optical fiber. Additionally, an orientation sensor is coupled to the tool and is operable to provide data regarding orientation of the tool. A processing system, which may include an optical interrogation system, cooperates with the optical fiber and with the orientation sensor to obtain acoustic data. For example, the processing system collects tool orientation data and also strain data obtained from a location along the wrapped optical fiber. The strain data results from excitation of an acoustic signal from a suitable acoustic source.

主权项

1. A method for geophysical exploration, comprising:
wrapping an optical fiber around a downhole tool; coupling an orientation sensor to the downhole tool; moving the downhole tool and the orientation sensor downhole into a borehole surrounded by a formation; exciting acoustic waves into the formation; obtaining strain data from the optical fiber wrapped around the downhole tool, the strain data resulting from effects of the acoustic waves acting on the optical fiber; receiving orientation data regarding the downhole tool from the orientation sensor; and combining the strain data and the orientation data in a processor system to obtain oriented acoustic data indicative of characteristics of the formation.