Vertical Seismic Profiling While Drilling Using Passive Monitoring Data

Abstract

Summary We extract seismic-while-drilling (SWD) data from passive seismic recordings acquired with the Grane PRM array. The drill-bit pilot trace used for correlation is estimated by means of array beam forming. We observe a strong coherent signal emanating from the drill bit during times of actual drilling, when the rate of penetration (ROP) is high. For one PRM node near the wellhead, we assemble the while-drilling signals into regular depth intervals along a portion of the deviated well path. The resulting dataset is equivalent to a reverse vertical seismic profile (RVSP). We apply a check-shot VSP processing flow to extract reflected signals from below the drill bit that can be used for interpretation. We observe a good match of the RVSP corridor and corridor stack with a crossline section of the 3D seismic at Grane. This validates that passively collected seismic-while-drilling data at Grane may be utilized to look ahead of the drill bit. Using an ocean bottom cable, we can produce VSP information in real-time while drilling without the need to stop and pull the drill string for wireline deployment.