method for geophysical monitoring inside a wellbore, apparatus for geophysical monitoring in a wellbore, and use of fiber optic distributed acoustic sensing

摘要

This application relates to methods and apparatus for geophysical monitoring within wellbores. The method involves interrogating an optical fibre (106) deployed along substantially the entire length of the wellbore (201) to provide distributed acoustic sensing and detecting the acoustic response from substantially the entire length of the wellbore in response to a seismic stimulus (204). The acoustic returns from individual sensing portions of the optical fibre can be processed to provide a profile such as a vertical seismic profile (VSP). An acoustic response from the entire length of the well can be recorded using a single shot of the seismic source.