Carlo Janna, PhD

Associate Professor in Numerical Analysis

E-mail: carlo.janna@unipd.it

Curriculum Vitae:
CV_Janna.pdf

M3E website:
www.m3eweb.it

Software:
Software

Matrici:
Matrici

Download:
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Materiale Didattico:
Materiale Didattico


Thesis Proposals:

1 - Defining a better heuristic for the Newton method in reservoir simulation

Typical reservoir simulation involves the repeated solution in time of highly non-linear systems of equations as several quantities, such as relative permeability, capillary pressure, elastic storage, depend on the unknown solution at the current time. The Newton method, on its side, is an iterative scheme requiring the solution of a sequence of linearized system at each step, which are typically solved through preconditioned iterative methods, e.g., algebraic multigrid (AMG).
In principle, since the systems change at every Newton step, the most conservative strategy is that of setting-up a new preconditioner for every non-linear solve. However, since the preconditioner set-up stage could be quite expensive, a more efficient alternative could be that of computing a new preconditioner or updating an existing one only when the system matrix changes significantly.
The present proposal focuses on studying optimal choices for preconditioner reset or update in reservoir simulation. The thesis will be carried out in collaboration with ENI and will involve an extensive use of Echelon, the ENI-proprietary reservoir simulation model, on modern parallel computers. The student will learn how to run an up-to-date reservoir simulator on real or realistic field, will learn how to work on a parallel computer using a load-leveler and finally will learn the basis of parallel programming and numerical methods.

External co-supervisors:
Alberto Cominelli, Mario Tacconi, ENI E&P
Leonardo Patacchini, Stone Ridge Technology

2 - Improving the iterative solution of linear systems arising from reservoir simulation models

Reservoir simulation software requires the solution in time of several non-linear systems of the equations, which are typically solved with the Newton method. Newton, in turn, involves the solution of a sequence of large and sparse linear systems which are very often solved through algebraic multigrid (AMG). Though being extremely efficient, the time spent for the AMG solve accounts for up to 90% of the total simulation time in real world problems, so that it is of paramount importance increasing its efficiency.
For instance, Echelon, the reservoir simulation software used in ENI, relies on the linear solver in the GAMPACK library which guarantees excellent performance. However, other solver packages are available offering promising improvements in the context of AMG, such as aggressive coarsening techniques, extended and long-range prolongations, filtering or advanced smoothers.
The aim of this thesis is exploring the effectiveness of these approaches, currently implemented in other packages such as Hypre or Chronos and evaluate their impact on real world reservoir and geomechanical models.
The thesis will be carried out in collaboration with ENI and will involve the use of GAMPACK and other linear solvers on modern parallel computers. The student will learn how to use and customize state-of-the-art parallel linear solvers, will learn how to work on a parallel computer using a load-leveler and, finally, will learn the basis of parallel programming.

External co-supervisors:
Alberto Cominelli, Silvia Monaco, Mario Tacconi, ENI E&P
Leonardo Patacchini, Stone Ridge Technology

Papers in International Journals:

48 - L. Bergamaschi, M. Ferronato, G. Isotton, C. Janna, A. Martinez. Parallel matrix-free polynomial preconditioners with application to flow simulations in discrete fracture networks. Computer and Mathematics with Applications, pp. 60-70, 2023.

47 - C. Janna, A. Franceschini, J. Schroder and L. Olson. Parallel energy-minimization prolongation for algebraic multigrid. SIAM Journal on Scientific Computing, 45, pp. A2561-A2584, 2023.

46 - A. Franceschini, M. Ferronato, M.Frigo and C. Janna. A Reverse Augmented Constraint preconditioner for Lagrange multiplier methods in contact mechanics. Computer Methods in Applied Mechanics and Engineering, 393, 114632, 2022.

45 - G. Isotton, M. Bernaschi and C. Janna. A GPU-accelerated adaptive FSAI preconditioner for massively parallel simulations. International Journal of High Performance Computing Applications, 36~(2), pp. 153-166, 2022.

44 - G. Isotton, M. Frigo, N. Spiezia and C. Janna. Chronos: A general purpose classical AMG solver for high performance computing. SIAM Journal of Scientific Computing, 43, pp. C335-C357, 2021.

43 - L. Gazzola, M. Ferronato, M. Frigo, C. Janna, P. Teatini, C. Zoccarato, M. Antonelli, A. Corradi, M.C. Dacome, S. Mantica. A novel methodological approach for land subsidence prediction through data assimilation techniques. Computational Geosciences, 25, pp. 1731-1750, 2021.

42 - G. Isotton, P. Teatini, M. Ferronato, C. Janna, N. Spiezia, S. Mantica and G. Volonte. Robust numerical implementation of a 3D rate-dependent model for reservoir geomechanical simulations. International Journal for Numerical and Analytical Methods in Geomechanics, 43, pp. 2752-2771, 2019.

41 - M. Ferronato, A. Franceschini, C. Janna, N. Castelletto and H. Tchelepi. A general preconditioning framework for coupled multiphysics problems with application to contact- and poro-mechanics. Journal of Computational Physics, 398, 108887, 2019.

40 - C. Zoccarato, M. Ferronato, A. Franceschini, C. Janna and P. Teatini. Modeling fault activation due to fluid production: Bayesian update by seismic data. Computational Geosciences, 23(4), pp. 705-722, 2019.

39 - A. Franceschini, V. A. Paludetto Magri, G. Mazzucco, N. Spiezia, and C. Janna. A robust adaptive algebraic multigrid linear solver for structural mechanics. Computer Methods in Applied Mechanics and Engineering, 352, pp. 389-416, 2019.

38 - M. Bernaschi, M. Carrozzo, A. Franceschini and C. Janna. A Dynamic Pattern Factored Sparse Approximate Inverse Preconditioner on Graphics Processing Units. SIAM Journal of Scientific Computing, 41, pp. C139-C160, 2019.

37 - V. A. Paludetto Magri, A. Franceschini, and C. Janna. A novel AMG approach based on adaptive smoothing and prolongation for ill-conditioned systems. SIAM Journal of Scientific Computing, 41, pp. A190-A219, 2019.

36 - V. A. Paludetto Magri, A. Franceschini, M. Ferronato, and C. Janna. Multilevel Approaches for FSAI Preconditioning. Numerical Linear Algebra with Applications, 25, 2018.

35 - S. Ye, A. Franceschini, Y. Zhang, C. Janna, X. Gong, J. Yu and P. Teatini. Earth fissure development caused by extensive aquifer exploitation. A novel modelling approach applied to the Wuxi case study, China. Water Resources Research, 54, pp. 2249-2269, 2018.

34 - H.T. Honorio, C.R. Maliska, M. Ferronato and C. Janna. A stabilized element-based finite volume method for poroelastic problems. Journal of Computational Physics, 364, pp. 49-72, 2018.

33 - A. Franceschini, V. Magri Paludetto, M. Ferronato and C. Janna. A robust multilevel approximate inverse preconditioner for symmetric positive definite matrices. SIAM Journal on Matrix Analysis and Applications, 39, pp. 123-147, 2018.

32 - N. Spiezia, M. Ferronato, C. Janna and P. Teatini. A two-invariant pseudo-elastic model for reservoir compaction. International Journal for Numerical and Analytical Methods in Geomechanics, 41, pp. 1870-1893, 2017.

31 - A. Zanette, M. Ferronato and C. Janna. Enriching the Finite Element method with meshfree particles in structural mechanics. International Journal for Numerical Methods in Engineering, 110, pp. 675-700, 2017.

30 - R. Baggio, A. Franceschini, N. Spiezia and C. Janna. Rigid body modes deflation of the preconditioned conjugate gradient in the solution of discretized structural problems. Computers & Structures, 18, pp. 15-26, 2017.

29 - F. Comola, C. Janna, A. Lovison, M. Minini, A. Tamburini, and P. Teatini. Efficient global optimization of reservoir geomechanical parameters based on SAR-derived ground displacements. Geophysics, 81, pp. M23-M33, 2016.

28 - A. Franceschini, M. Ferronato, C. Janna, and P. Teatini. A novel Lagrangian approach for a stable numerical simulation of fault and fracture mechanics. Journal of Computational Physics, 314, pp. 503-521, 2016.

27 - M. Ferronato, C. Janna, and G. Pini. Parallel Jacobi-Davidson with Block FSAI preconditioning and controlled inner iterations. Numerical Linear Algebra with Applications, 23, pp. 394-409, 2016.

26 - M. Bernaschi, M. Bisson, C. Fantozzi, and C. Janna. A FSAI preconditioned conjugate gradient solver on GPUs.. SIAM Journal of Scientific Computing, 38, pp. C53-C72, 2016.

25 - M. Ferronato, C. Janna, and G. Gambolati. A novel Factorized Sparse Approximate Inverse preconditioner with supernodes. Procedia Computer Science, 51, pp. 266-275, 2015.

24 - C. Janna, N. Castelletto and M. Ferronato. The effect of graph partitioning techniques on parallel Block FSAI preconditioning: a computational study. Numerical Algorithms, 68 (4), pp. 813-836, 2015. DOI: 10.1007/s11075-014-9873-5.

23 - C. Janna, M. Ferronato, F. Sartoretto and G. Gambolati. FSAIPACK: a software package for high performance Factored Sparse Approximate Inverse preconditioning. ACM Transactions on Mathematical Software, Vol. 41, N. 2, Art. 10, 2015.

22 - C. Janna, M. Ferronato and G. Gambolati. The use of supernodes in factored sparse approximate inverse preconditioning. SIAM Journal of Scientific Computing, 37, pp. C72-C94, 2015.

21 - M. Ferronato, C. Janna, G. Pini. A generalized Block FSAI preconditioner for nonsymmetric linear systems. Journal of Computational and Applied Mathematics, 256, pp. 230-241, 2014.

20 - C. Janna, M. Ferronato, G. Gambolati. Enhanced Block FSAI preconditioning using Domain Decomposition techniques. SIAM Journal on Scientific Computing, 35, pp. S229-S249, 2013.

19 - M. Ferronato, N. Castelletto, G. Gambolati, C. Janna, P. Teatini. II cycle compressibility estimate from satellite measurements. Geotechnique, 63, pp. 479-486, 2013.

18 -N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, D. Marzorati, P. Teatini. Can natural fluid pore pressure be safely exceeded om storing gas underground? Engeneering Geology, 153, pp. 35-44, 2013.

17 - M. Ferronato, C. Janna, G. Pini. Efficient parallel solution to large-size sparse eigenproblems with block FSAI preconditioning. Numerical Linear Algebra with Applications, 19, pp. 797-815, 2012.

16 - C. Janna, M. Ferronato, G. Gambolati. Parallel inexact constraint preconditioning for ill-conditioned consolidation problems. Computational Geosciences, 16, pp. 661-675, 2012.

15 - C. Janna, N. Castelletto, M. Ferronato, G. Gambolati, P. Teatini. A geomechanical transversely isotropic model of the Po River basin using PSInSAR derived horizontal displacement. International Journal of Rock Mechanics & Mining Sciences, 51, pp. 105-118, 2012.

14 - M. Ferronato, C. Janna, G. Pini. Shifted FSAI preconditioners for the efficient parallel solution of non-linear groundwater flow models. International Journal for Numerical Methods in Engineering, 89, pp. 1707-1719, 2012.

13 - M. Ferronato, C. Janna, G. Pini. Parallel solution to ill-conditioned FE geomechanical problems. International Journal for Numerical and Analytical Methods in Geomechanics, 36, pp. 422-437, 2012.

12 - C. Janna, M. Ferronato. Adaptive pattern research for Block FSAI preconditioning. SIAM Journal on Scientific Computing, 33, pp. 3357-3380, 2011.

11 - G. Gambolati, M. Ferronato, C. Janna. Preconditioners in computational geomechanics: a survey. International Journal for Numerical and Analytical Methods in Geomechanics, 35, pp. 980-996, 2011.

10 - P. Teatini, N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, E. Cairo, D. Marzorati, D. Colombo, A. Ferretti, A. Bagliani, F. Bottazzi. Geomechanical response to seasonal gas storage in depleted reservoirs: a case study in the Po river basin, Italy. Journal of Geophysical Research, 116, F02002, doi:10.1029/2010JF001793, 2011.

9 - N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, P. Teatini. Numerical modeling of rock/casing interaction in radioactive-marker boreholes of the Northern Adriatic basin, Italy. SPE Reservoir Evaluation & Engineering, 13, pp. 906-913, 2010.

8 - C. Janna, M. Ferronato, G. Gambolati. A Block FSAI-ILU parallel preconditioner for symmetric positive definite linear systems. SIAM Journal on Scientific Computing, 32, pp. 2468-2484, 2010.

7 - M. Ferronato, G. Gambolati, C. Janna, P. Teatini. Geomechanical issues of anthropogenic CO2 sequestration in exploited gas fields. Energy Conversion and Management, 51, pp. 1918-1928, 2010.

6 - C. Janna, A. Comerlati, G. Gambolati. A comparison of projective and direct solvers for Finite Elements in elastostatics. Advances in Engineering Software, 40, pp. 675-685, 2009.

5 - C. Janna, M. Ferronato, G. Gambolati. Multilevel incomplete factorizations for the iterative solution of non-linear FE problems. International Journal for Numerical Methods in Engineering, 80, pp. 651-670, 2009.

4 - M. Ferronato, C. Janna, G. Gambolati. Mixed constraint preconditioning in computational contact mechanics. Computer Methods in Applied Mechanics and Engineering, 197, pp. 3922-3931, 2008.

3 - M. Ferronato, G. Gambolati, C. Janna, P. Teatini. Numerical modelling of regional faults in land subsidence prediction above gas/oil reservoirs. International Journal for Numerical and Analytical Methods in Geomechanics, 32, pp. 633-657, 2008.

2 - M. Ferronato, G. Gambolati, P. Teatini, C. Janna. Letter to the editor of Petroleum Science & Engineering: Comment on "Casing influence while measuring in situ reservoir compaction" by P. Macini, E. Mesini, V.A. Salomoni and B.A. Schrefler [J. Pet. Sci. Eng. 50 (2006), 40 54]. Journal of Petroleum Science and Engineering, 60, pp. 67-70, 2008.

1 - M. Ferronato, G. Gambolati, P. Teatini, C. Janna. Casing influence in reservoir compaction measurement by radioactive markers in the Northern Adriatic, Italy. International Journal of Geomechanics, 7, pp. 444-447, 2007.



Book chapters:

2 - C. Janna, M. Ferronato, G. Gambolati. Approximate inverse preconditioning for the solution of large sparse linear systems In B.H.V. Topping and P. Ivanyi (eds.), Computational Technology Review, vol. 7, pp. 25-41, 2013. Saxe-Coburg Publication, Stirlingshire (UK).

1 - C. Janna, M. Ferronato, G. Gambolati. Two-level block preconditioners for contact problems. In G. Zavarise and P. Wriggers (eds.), Trends in Computational Contact Mechanics, Lecture Notes in Applied and Computational Mechanics, vol. 58, pp. 211-226, 2011. Springer Verlag, Berlin Heidelberg (Germany).



Papers in Proceedings of International Conferences:

37 -A. Alsalti-Baldellou, C. Janna, X. Alvarez-Farre and F. X. Trias, Low-rank corrections for increasing the arithmetic intensity of the preconditioners, ParCFD2023, 34th International Conference on Parallel Computational Fluid Dynamics, May 29-31 2023, Cuenca Ecuador.

36 -A. Alsalti-Baldellou, C. Janna, X. Alvarez-Farre and F. X. Trias, Exploiting Symmetries for Preconditioning Poisson’s Equation in CFD Simulations, Proceedings of the Platform for Advanced Scientific Computing Conference, PASC 2023.

35 -M. Frigo, G. Isotton, C. Janna, N. Spiezia, M. Ferronato, A. Franceschini, A. Filippini, G. Scrofani, A GPU-Accelerated Simulator for Challenging Extreme-Scale Geomechanical Models, Society of Petroleum Engineers - SPE Reservoir Simulation Conference, RSC 2023.

34 -G. Isotton, A. Franceschini and C. Janna. On the construction of AMG prolongation through energy minimization, Proceedings of the Platform for Advanced Scientific Computing Conference, PASC 2022, 13.

33 -G. Isotton, M. Frigo, N. Spiezia, S. Koric, Q. Lu and C. Janna. A general-purpose amg li- near solver for high performance computing, 14th World Congress on Computational Mechanics (WCCM) ECCOMAS Congress 2020, 19-24 July 2020, Paris, France, F. Chinesta, R. Abgrall, O. Allix and M. Kaliske (Eds)

32 -V. A. Paludetto Magri, A. Franceschini, M. Ferronato and C. Janna. A novel AMG approach ba- sed on adaptive smoothing and prolongation for reservoir simulations, 16th European Conference on the Mathematics of Oil Recovery, ECMOR 2018.

31 -M. Ferronato, H. T. Honorio, C. Janna and C. R. Maliska. An Oscillation-Free Finite Volume Method for Poroelasticity. Proceedings of Numerical Mathematics and Advanced Applications: ENUMATH 2017, in Lecture Notes in Computational Science and Engineering 126, 2018.

30 -M. Ferronato, V. A. Paludetto Magri, C. Janna and A. Franceschini. M3E_LINSOL: A Scalable Linear Solver Package for Reservoir Simulations on Massively Parallel Computers. SPE Reservoir Simulation Conference, Montgomery TX, February 20-22, 2017.

29 -A. Zanette, M. Ferronato, C. Janna. Enriching the Finite Element Method with meshfree techniques in structural mechanics. Procedia of Applied Mathematics and Mechanics, 15, pp. 691-692, 2015.

28 -A. Franceschini, P. Teatini, C. Janna, M. Ferronato, G. Gambolati, S. Ye, D. Carreon-Freyre. Modelling ground rupture due to groundwater withdrawal: applications to test cases in China and Mexico. Proceedings of the International Association of Hydrological Sciences, pp. 63-68, 2015.

27 - M. Ferronato, C. Janna, G. Gambolati and F. Sartoretto. High Performance Computing preconditioners for the efficient solution of geomechanical models. In Oka, Murakami, Uzuoka and Kimoto (eds.), Computer Methods and Recent Advances in Geomechanics V, pp. 153-158, 2014.

26 - C. Zoccarato, M. Ferronato, G. Gambolati, C. Janna, P. Teatini, A. Alzraiee and D. Baù. Data assimilation of SAR-based measurements for geomechanical characterization. In Oka, Murakami, Uzuoka and Kimoto (eds.), Computer Methods and Recent Advances in Geomechanics V, pp. 1229-1234, 2014.

25 - A. Lovison, F. Comola, P. Teatini, C. Janna, M. Ferronato, M. Putti, and G. Gambolati. Model calibration of a geomechanical problem with efficient global optimization. Dolomites Research Notes on Approximation, 6, pp. 140-150, 2013.

24 - N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, P.Teatini. Compartmentalization effects in geologic CO2 sequestration. A case study in an offshore reservoir in Italy. In C. Hellmich et al. (eds.), Poromechanics V, pp. 1265-1270, 2013. American Society of Civil Engineers, USA.

23 - M. Ferronato, C. Janna, G. Gambolati. A parallel Domain Decomposition-Block FSAI preconditioner for geomechanical applications, In B. Amaziane et al. (eds.), Proceedings of the 5th International Conference on Approximation Methods and Numerical Modelling in Environment and Natural Resources, 2013. Editorial Universidad de Granada, Granada, Spain.

22 - N. Castelletto, P. Teatini, C. Janna, G. Gambolati, M. Ferronato, M. Politi. CO2 geological sequestration: a numerical study of a multi-compartment reservoir in the northern Adriatic sea, Italy. In A.J. Valocchi (ed.), Proceedings of the XIX International Conference on Computational Methods in Water Resources, pp. 303-310, 2012. University of Illinois at Urbana-Champaign, IL.

21 - M. Ferronato, N. Castelletto, C. Janna. Block FSAI performance with graph partitioning in large size subsurface problems. In A.J. Valocchi (ed.), Proceedings of the XIX International Conference on Computational Methods in Water Resources, pp. 176-183, 2012. University of Illinois at Urbana-Champaign, IL.

20 - C. Janna, M. Ferronato, G. Gambolati. A parallel adaptive block FSAI preconditioner for Finite Element geomechanical models. In F.L. Gaol and Q.V. Nguyen (eds.), Proceedings of the 2011 2nd International Congress on Computer Applications and Computational Science, Advances in Intellingent and Soft Computing, vol. 145, issue vol. 2, pp. 331-338, 2012. Springer Verlag, Berlin Heidelberg (Germany).

19 - M. Ferronato, C. Janna, G. Pini, G. Gambolati. A parallel Jacobi-Davidson algorithm with Block FSAI preconditioning. In T.E. Simos et al. (eds.), Numerical Analysis and Applied Mathematics, pp. 1694-1697, doi: 10.1063/1.3636935, 2011. American Institute of Physics Conf. Proc. 1389, Melville (NY).

18 - M. Ferronato, C. Janna, G. Gambolati. A novel parallel preconditioner for ill-conditioned FE consolidation problems. In N. Khalili and M. Oeser (eds.), Computer Methods for Geomechanics: Frontiers and New Applications, Vol. 1, pp. 72-76, 2011. Centre for Infrastructure Engineering and Safety, Sydney, Australia.

17 - M. Ferronato, C. Janna, G. Gambolati. Parallel preconditioners for saddle-point problems. In P. Ivànyi and B.H.V. Topping (eds.), Proceedings of the Second International Conference on Parallel, Distributed, Grid and Cloud Computing for Engineering, paper no. 37, 2011, doi:10.4203/ccp.95.37. Civil-Comp Press, Stirlingshire (UK).

16 - N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, P. Teatini, D. Marzorati, E. Cairo, D. Colombo, A. Ferretti, A. Bagliani, F. Bottazzi. Sustainable underground gas storage activities in a Po plain gas field, northern Italy. In Proceedings of 2011 Offshore Mediterranean Conference and Exhibition Cd-Rom, Ravenna (Italy), 2011.

15 - C. Janna, M. Ferronato, G. Gambolati, P. Teatini. Simulation of ground failure due to groundwater pumping. In Land Subsidence, Associated Hazards and the Role of Natural Resources Development, pp. 133-135, 2010. IAHS Publication no. 339.

14 - N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, P. Teatini. Thermo-poro-elastic effects in the anthropogenic uplift of Venice by deep seawater injection. In Land Subsidence, Associated Hazards and the Role of Natural Resources Development, pp. 96-101, 2010. IAHS Publication no. 339.

13 - P. Teatini, G. Gambolati, N. Castelletto, M. Ferronato, C. Janna, E. Cairo, D. Marzorati, D. Colombo, A. Ferretti, A. Bagliani, F. Bottazzi, F. Rocca. Monitoring and modelling of 3-D ground movements induced by seasonal gas storage in deep reservoirs. In Land Subsidence, Associated Hazards and the Role of Natural Resources Development, pp. 68-75, 2010. IAHS Publication no. 339.

12 - C. Janna, M. Ferronato, G. Gambolati. A novel hybrid FSAI-ILU preconditioner for the efficient parallel solution of large size sparse linear systems. In B.H.V. Topping et al. (eds.), Proceedings of the Seventh International Conference on Engineering Computational Technology, paper no. 3, 2010, doi:10.4203/ccp.94.3. Civil-Comp Press, Stirlingshire (UK).

11 - N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, P. Teatini, D. Marzorati, E. Cairo, D. Colombo, A. Ferretti, A. Bagliani, S. Mantica. 3D geomechanics in UGS projects. A comprehensive study in northern Italy. In Proceedings of the 44th US Rock Mechanics Symposium, paper no. 185, 2010. American Rock Mechanics Association, Salt Lake City (UT).

10 - M. Ferronato, G. Gambolati, C. Janna, P. Teatini. Poromechanical modeling of CO2 sequestration in exploited gas fields. In H.I. Ling et al. (eds.), Poromechanics IV, pp. 171-176, 2009. DEStech Publication, Lancaster, PA.

9 - C. Janna, M. Ferronato, G. Gambolati. Efficient multilevel preconditioners for large size geomechanical simulations. In S. Pietruszczak et al. (eds.), Computational Geomechanics (ComGeo I), pp. 359-369, 2009. IC2E International Centre for Computational Engineering, Rhodes, Greece.

8 - G. Gambolati, M. Ferronato, C. Janna. Preconditioners for finite element consolidation. In W.H. Chen and S.N. Atluri (eds.), Advances in Computational & Experimental Engineering and Sciences (Proceedings of ICCES09), pp. 26-32, 2009. TechScience Press, ISBN: 978-0-9717880-9-1.

7 - N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, I. Salce, P. Teatini. Geomechanical effects of gas storage in depleted gas fields. In A. Majdi and A. Ghazvinian (eds.), New Horizons in Rock Mechanics, Developments and Applications, Proc. ISRM Int. Symp. 2008 - 5th Asian Rock Mechanics Symposium, Vol. 2, pp. 1015-1021, 2008.

6 - M. Ferronato, G. Gambolati, C. Janna. Efficient block preconditioners for the numerical modelling of geological faults. In D. N. Singh (ed.), Proceedings of the 12th International Conference of the International Association of Computer Methods and Advances in Geomechanics, pp. 244-250, 2008.

5 - C. Janna, M. Ferronato, G. Gambolati. Multilevel incomplete factorizations for nonlinear FE problems in geomechanics. In H. Murakawa et al. (eds.), Advances in Computational & Experimental Engineering and Sciences (Proceedings of ICCES08), pp. 611-616, 2008. TechScience Press, ISBN: 978-0-9717880-5-3.

4 - C. Janna, M. Ferronato, G. Gambolati. Block preconditioning for the FE solution to contact problems. In T.E. Simos et al. (eds.), Numerical Analysis and Applied Mathematics, International Conference, pp. 284-287, 2007. American Institute of Physics, Melville (NY).

3 - M. Ferronato, G. Pini, G. Gambolati, C. Janna. Symmetric and unsymmetric block preconditioning for the iterative solution to FE coupled consolidation. In T.E. Simos et al. (eds.), Numerical Analysis and Applied Mathematics, International Conference, pp. 216-219, 2007. American Institute of Physics, Melville (NY).

2 - N. Castelletto, M. Ferronato, G. Gambolati, C. Janna, P. Teatini. Modelling geomechanical effects of the well case on radioactive marker measurements of the Northern Adriatic, Italy. In Proceedings of 2007 Offshore Mediterranean Conference and Exhibition Cd-Rom, Ravenna (Italy), 2007.

1 - A. Comerlati, C. Janna, G. Gambolati. Reorderings for the iterative solution of hybrid elastic structures. In Proceedings of the Eight International Conference on Computational Structures Technology (CST 2006), September 12-15 2006, Las Palmas de Gran Canaria, Spain, paper 175.

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