Multi-scale Characterization of Coupling Mechanisms for Evolving Permeability in Oil/Gas Bearing Sediments Compaction

Abstract

A proper understanding and eventual assessment of reservoir compaction and land subsidence is crucial for decision-making in petroleum and gas extraction industry. This paper presents a multi-scale multi-physics study of coupling mechanisms in the long-term compaction of oil/gas bearing sediments, also known as aging. The principal goal of this work is to quantify such coupling mechanisms at different scales and link phenomena occurring at micro- and meso-scales to a mathematical model formulated at a macroscopic continuum level. The interaction between mechanical and non-mechanical processes, originating from intergranular damage and dissolution was examined through modeling the involved phenomena at their respective micro- and meso-scales. Two major consequences that result from the intensified chemo-mechanical coupling were investigated: porosity reduction, and subsequent stiffness and permeability evolution. It appears that permeability is mildly affected by the contact area increase, and for most of the duration, by the precipitation of the mineral solute; stiffening of the grain system results from the mineral precipitation and the consequent redistribution of mass within the pore space.