SUBSIDENCE INDUCED BY THE PRODUCTION OF FLUIDS

This article is devoted to the investigation of soil surface subsidenc e caused by the production of fluids (water, oil and gas). It first de scribes the methods available for measuring this subsidence, methods t hat have become extremely accurate today. Cases are selected from the literature to identify the mechanisms causing subsidence: reservoir an d aquifer compaction associated with depletion, mechanisms connected w ith fluid injections in specific cases (thermal creep, action of water on chalk). These mechanisms must be taken into account by models prog ressively enriched with geological, petrophysical and mechanical descr iptions, substantiated by in situ measurements. Subsidence control dem ands the control of the in situ pressure, maintained by a fluid compat ible with the formation. If this control is applied early enough, the risk of subsidence is virtually nit.