Reservoir compaction and land subsidence occur when large amounts of pore fluids have been withdrawn from underground reservoirs. Magnitudes of compaction and subsidence in oil and gas fields vary greatly depending on characteristics of the rock and field geometry. In this presentation, we briefly describe the causes and effects of compaction and subsidence in the oilfield, and describe how early-stage assessments are performed. We present a case study of the assessment for one oil field in the North Sea for IOG, including analytical and numerical calculations, comparison to well-studied analog fields and results. Meet the Instructor:. Senior Geomechanicist.