Seismic While Drilling in the Grane Field

Using a standard surface seismic source and a set of acoustic receivers placed within the bottomhole assembly of a drillstring provides data equivalent to conventional wireline gathers, but also allows data acquisition in sections normally not accessible with cable based systems. In addition the data has the value of real-time availabilty. With this Seismic While Drilling (SWD) technique, geosteering decisions and formation characterisations can be made early during the drilling phase of the reservoir exploration especially in the long lateral sections typical for North Sea offshore production wells. A special benefit comes from the use of hydrophone data gathered during SWD deployments, not normally available in wireline VSP measurements. The potential of SWD will be demonstrated in an SWD case study from the Grane Field in the North Sea.