ELABORATION OF AN ELASTOPLASTIC MODEL FOR HIGH-POROSITY CHALKS - APPLICATION TO THE COMPACTION OF PETROLEUM RESERVOIRS

This paper presents a study of the compaction of petroleum reservoirs applied to very porous carbonate rocks such as chalk. In production es timates made in reservoir engineering, the processing of the mechanica l problem is often greatly simplified. Good modelling of how materials behave gives special consideration to the influence of mechanical def ormations on fluid recovery. After an analysis of the mechanical behav iour of very porous chalks, an elastoplastic behaviour model is derive d so as to reproduce the principal experimental observations. This beh aviour model can then be used to perform local simulations of the mech anical behaviour of a reservoir undergoing depletion and thus to demon strate the importance of the stress path and the initial stress state on the deformation of materials and hence on the recovery rate.