One Man’s Noise is Another Man’s Signal: Semblance Monitoring for Safe Drilling and Drilling Risk Detectionbe

In this paper, we present some applications of passive seismic data recorded by Permanent Reservoir Monitoring systems installed on the sea bottom, and processed in real time during drilling operation. More precisely, the computation of a semblance attribute in the region close to the well allows not only to track precisely the drillbit position in real time but also to detect, locate and analyze drilling incidents. We show examples of mud loss detection, one of the major drilling risks occurring in injectite fields such as the Grane field in the North Sea, and discuss how the displayed technology could help optimizing the drilling operations and better planning potential side-tracks.