Raoof Gholami - Department of Petroleum Engineering, Curtin University, Malaysia

There have been many studies on reservoir compaction where different mechanisms being suggested as the reasons behind the integrity of unconsolidated reservoirs during production. Theory of poroelasticity is often used to evaluate the likelihood of compaction under these circumstances, but it is often failed to explain the creep behavior of unconsolidated formations. In this study, attempts are made to have a closer look into the compaction mechanism of deep-water sandstone reservoirs. The results obtained indicated that depending on the type of clays, confining pressure and the loading rate, sandstone may exhibit a viscoelastic or viscoplastic behavior during compaction. The results of this study suggest that detailed analysis of clays is required for correct simulations and to answer questions related to geomechanical responses of unconsolidated sandstones under different stress conditions. 

Unconsolidated sandstone, clays, Creep, Viscoelasticity, compaction