Finite strain elastoplastic solutions for mechanical compaction in sedimentary basins
Paulo S. B. Lemos1; André Brüch1; Eurípedes do A. Vargas Jr.2; Samir Maghous1
1 Department of Civil Engineering, Federal University of Rio Grande do Sul; 2 Pontifícia Universidade Católica do Rio de Janeiro
doi:10.20906/CPS/CILAMCE2017-0117
Resumo
Sedimentary basins are open material systems with continuous supply of organic and inorganic material which are of great economic interest as they are favorable environments for natural hydrocarbons formation. In this context, numerical basin simulators are used to describe the evolution of these structures in order to optimize exploration processes. This work presents analytical solutions for purely mechanical deformation of sedimentary basins in the context of finite irreversible transformation which may provide useful references for the verification of numerical simulators. The analysis is restricted to materials with high permeability, for which the drained behavior is acceptable. For purely mechanical compac-tion, due to the great variation of porosity, an elastoplastic constitutive law is used in the context of large irreversible deformations. The elastic properties and sediment hardening are also affected by porosity variation. These effects are introduced by additional terms, deduced from micromechanics, in the equations of state, as well as derivation of an expression for the hardening law, which avoids the development of negative porosities under high isotropic compression. The analytical approach is compared to numerical solutions derived from a finite element simulator, specifically designed to deal with sedimentary basins in the context of large irreversible deformations.
Palavras-chave: sedimentary basin; finite plasticity; elastoplastic coupling