Simulador de meios porosos saturados elastoplasticos / Numerical simulator of saturated elastoplastic porous media

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The exploration of mineral resources is growing in importance in the Brazilian economy. Since the environments in which these resources are found are becoming increasingly more complex and challenging for the production phase, currently unavailable knowledge and technologies are required to produce these reserves. In the particular well drilling and completion areas, the comprehension and numerical reproduction of the hydromechanical behavior of rocks in such deep environments become an issue. The observed reversible and irreversible strain behavior of rocks is commonly modeled by the elastoplasticity theory. The hydraulic modeling of a porous media leads to poroelastoplastic couplings of several kinds, but an unique text on poroelastoplastic postulation concerning the plastic counterpart of fluid storage in the formation had not been found in the bibliography. Thus, this thesis aims for the development of a consistent poroelastoplastic formulation applied to the elastoplastic consitutive models of Lade-Kim and Sandler &Dimaggio. These models embody isotropic hardening and allow the correct modeling of rock compaction and controled dilatancy, resembling the rock behavior in a more reliable sense than the conventional and largerly applied models based on the Mohr-Coulomb yield surface. The author presents a generic elastoplastic decomposition algorithm with adaptive substepping in order to constrain the ODE s integration deviation. A consistent jacobian operator evaluation becomes feasible by the adoption of automatic differentiation strategies. The final C++ implemented generic and object-oriented elastoplastic decomposition and elastoplastic and poroelastoplastic simulation modules extend the PZ scientific computation environment to the simulation of such problems. The resultant algorithms presented high computational robustness and mechanical and hydromechanical well drilling behavior agreeing to the author s experience

ASSUNTO(S)

mecanica das rochas finite element method elastoplasticidade metodos dos elementos finitos plasticidade elastoplasticity rock mechanics plasticity

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