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SUMMARY:Coupled simulation of faulted porous media
DTSTART:20170324T121500
DTEND:20170324T131500
DTSTAMP:20260427T200809Z
UID:671054b3ae5a4287d3953d3191669e9485273b98bba630a9c98dcc0b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Dr  Massimiliano Ferronato\, Associate Professor at the 
 Department of Civil\, Environmental and Architectural Engineering\, ICEA\,
  University of Padova\, Italy\nAbstract : Poromechanical models are curren
 tly of common use in a number of engineering applications\, including the 
 management of deep hydrocarbon reservoirs\, used for both production and s
 torage purposes\, and the exploitation of groundwater resources from shall
 ow multi-aquifer systems. Recently\, an increasing interest is set at intr
 oducing discontinuity surfaces in the numerical models to simulate the mec
 hanics of geological faults. For instance\, such an activity is of paramou
 nt importance for ensuring the safety of the underground storage of wastes
  and hydrocarbons or predicting the possible seismicity triggered by the p
 roduction and injection of subsurface fluids.\nThe stable numerical modell
 ing of coupled poromechanics and the ground rupture formation\, however\, 
 is still a challenging task because of several issues\, namely: (1) the po
 re pressure numerical instability\, (2) the strong non-linearity induced b
 y the fault activation\, (3) the large number of unknowns\, and (4) the se
 vere ill-conditioning of the discrete problem. A number of different appro
 aches have been proposed in recent years to alleviate such difficulties. A
 mong them\, Mixed Finite Element formulations of coupled poromechanics and
  the use of Lagrange multipliers to prescribe the contact constraints on t
 he fault surfaces can help alleviate the numerical oscillations and provid
 e a mass-conservative approach\, but typically give rise to very large and
  ill-conditioned systems of algebraic equations.\nIn the present work\, th
 e mathematical weak formulation of the problem is modified in order to tak
 e into account the frictional energy along the activated fault portion acc
 ording to the principle of maximum plastic dissipation. This helps providi
 ng stable solutions with a fast convergence of the non-linear fault proble
 m. Moreover\, a novel class of efficient block preconditioners is develope
 d with the aim of accelerating the convergence of Krylov subspace methods 
 in complex real-world applications. The main idea relies on building cheap
  and effective approximations of the two-level Schur complement using a ph
 ysics-based approach. A purely algebraic formulation is also advanced\, th
 us allowing for the extension to different kinds of coupled multi-physics 
 problems.\nApplications of the proposed approach are presented in problems
  related to the generation of ground fractures due to groundwater withdraw
 al in arid regions\, fault reactivation in active hydrocarbon reservoirs\,
  and the exploitation of groundwater resources from a regional multi-aquif
 er system.\n\nBio : Massimiliano Ferronato got the Degree in Civil Enginee
 ring at the University of Padova (Italy) in 1998 and the PhD in Numerical 
 Geomechanics at the Technology University of Delft (The Netherlands) in 20
 03. Currently\, he is Associate Professor at the Department of Civil\, Env
 ironmental and Architectural Engineering of the University of Padova\, wit
 h teaching duties in the Numerical Methods classes.\nHe has authored and c
 o-authored more than 150 scientific papers published in international jour
 nals\, books and proceedings of international conferences\, and delivered 
 invited talks and lectures in several renowned symposia. The main scientif
 ic interests concern the numerical solution of the partial differential eq
 uations governing the mechanics of saturated and partially saturated porou
 s media\, with engineering applications in the field of subsurface hydrolo
 gy and petroleum engineering. He has been involved in a number of projects
  related to the numerical simulation of the geomechanical behavior of deep
  producing reservoirs\, geological formations used for storage purposes\, 
 e.g.\, CO2 sequestration\, and shallow multi-aquifer systems\, including t
 he analysis of fault activation\, fissure generation\, failure risk and la
 nd subsidence. The main scientific contributions concern the development a
 nd implementation of efficient and robust numerical models\, based on Fini
 te Element\, Mixed Finite Element and Finite Volume methods\, for the simu
 lation of geomechanical and fluid-dynamical processes in the subsurface. P
 articular care is paid to the implementation of accurate iterative solvers
  for the linear systems arising from such applications. He is the co-autho
 r of a number of original algorithms for both sequential and parallel comp
 utational architectures\, with the aim of accelerating the convergence and
  improving the robustness of iterative linear solvers.\n 
LOCATION:GCB330 http://plan.epfl.ch/?lang=fr&room=GCB330
STATUS:CONFIRMED
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