A VSP field trial using distributed acoustic sensing in a producing well in the North Sea

Acquiring vertical seismic profiling (VSP) data in a well using conventional wireline technology requires an array of seismic sensors to be lowered down the well to record the seismic signals generated by a shooting vessel on the surface. Due to the expenses involved when interrupting production this is rarely done in producing wells and VSP has not been economically feasible for monitoring purposes. The intelligent Distributed Acoustic Sensing (iDAS) technology enables a fibre-optic cable to be used as a massive acoustic sensor array. Presently, fibre optic cables suitable for iDAS measurements are deployed along many wells for other purposes. The iDAS can be retrofitted to existing optical fibres to acquire densely sampled acoustic measurements at low expense because the normal operation of the well is not disturbed.