The Role of Geophysics in Well Planning and Execution – A Case Study in the SNS

The role of Geophysics in the planning and drillings phases of a well is diverse, varying with the challenges of any given well. The objective of this paper is a case study highlighting how Geophysics contributed in both phases, including input stemming from recognition of hazards whilst drilling, to the successful outcome of a difficult well in the Southern North Sea. The well, initially stalled due to economics, was re-activated as a result of new depth conversion insights using PSDM velocity modelling; its trajectory was designed and modified to address hazards interpreted on seismic. In Shell Upstream International - Europe, Geophysics plays a pivotal role in the decision making during the well trajectory design phase and drilling phase. Whilst drilling, output from a parallel full-field review became available that included reprocessed seismic data. The superior quality of these data resulted in improved fault definition at target level and made a significant contribution to de-risk the well.