No abstract

Please cite this article as: Malgorzata Peszynska, Anna Trykozko, Gabriel Iltis, Steffen Schlueter, Dorthe Wildenschild, Biofilm growth in porous media: experiments, computational modeling at the porescale, and upscaling, Advances in Water Resources (2015), Highlights 1 • We use 3D imaging with a barium-based contrasting agent to obtain 2 porescale geometries filled with biofilm 3 • We simulate the flow in the porescale geometries with and without 4 biofilm, and upscale the results to the conductivities which compare 5 • well with the experimental values, and which show the dependence of 6 the degree of bioclogging on the flow rates 7 • We simulate biomass growth and transport coupled to the flow and 8 obtain morphologies similar to those in the experiment 9 • We show several reduced models for conductivities and their depen-10 dence on the biofilm growth Abstract 21 Biofilm growth changes many physical properties of porous media such 22 as porosity, permeability and mass transport parameters. The growth de-23 pends on various environmental conditions, and in particular, on flow rates. 24 Modeling the evolution of such properties is difficult both at the porescale 25 where the phase morphology can be distinguished, as well as during up-26 scaling to the corescale effective properties. Experimental data on biofilm 27 growth is also limited because its collection can interfere with the growth, 28 while imaging itself presents challenges. 29 In this paper we combine insight from imaging, experiments, and nu-30 merical simulations and visualization. The experimental dataset is based on 31 glass beads domain inoculated by biomass which is subjected to various flow 32 conditions promoting the growth of biomass and the appearance of a biofilm 33 phase. The domain is imaged and the imaging data is used directly by a 34 computational model for flow and transport. The results of the computa-35 tional flow model are upscaled to produce conductivities which compare well 36 with the experimentally obtained hydraulic properties of the medium. The 37 flow model is also coupled to a newly developed biomass-nutrient growth 38 model, and the model reproduces morphologies qualitatively similar to those 39 observed in the experiment.40 Keywords: 41 porescale modeling, imaging porous media, microtomography, reactive 42 transport, biomass and biofilm growth, parabolic variational inequality, 43 Lagrange multipliers, coupled nonlinear system, multicomponent 44 multiphase flow and transport in porous media 45 2

In this paper, we present a reduced model of methane hydrate formation in variable salinity conditions, with details on the equilibrium phase behavior adapted to a case study from Ulleung Basin. The model simplifies the comprehensive model considered by Liu and Flemings using common assumptions on hydrostatic pressure, geothermal gradient, and phase incompressibility, as well as a simplified phase equilibria model. The two-phase threecomponent model is very robust and efficient as well as amenable to various numerical analyses, yet is capable of simulating realistic cases. We compare various thermodynamic models for equilibria as well as attempt a quantitative explanation for anomalous spikes of salinity observed in Ulleung Basin.

No abstract

No abstract

No abstract

No abstract

We discuss the multi-block algorithm for an implicit black-oil model as implemented in a multi-phase simulator framework IPARS. The multi-block algorithm consists of decomposition of the simulation domain into multiple non-overlapping subdomains or blocks according to the geometric, geological and physical/chemical properties, distribution of wells, etc. Each block can have its own grid system, and the grids of the neighboring blocks can be non-matching on the interface, which allows, for example, for local grid refinement, or discrete fault or fracture modeling. Adjacent blocks are coupled across the interface by a set of conditions imposing continuity of the primary variables and component mass fluxes, which is realized with the use of special interface mortar variables. The resulting system is solved by an interface Newton procedure. Regularization techniques and preconditioners are proposed to improve the performance of the solver. The multi-block technique is effective and scalable, as shown by our numerical experiments. In addition, we present how the multi-block black-oil model has been used in the coupling of different physical models.