METHOD OF ACOUSTIC SURVEYING

摘要

The invention relates to the use of distributed optical fibre sensors for distributed acoustic sensing, and in particular, modal analysis of distributed acoustic data obtained in-well to monitoring well integrity. By determining one or more acoustic modes corresponding to distributed speed of sound measurements within the wellbore, and analysing variations in the distributed speed of sound measurement it is possible to derive information relating to a formation and/or fluid in the wellbore.