Tag: reconstruction models

Stochastic Reconstruction of Sandstones

Post author By R Hilfer
Post date February 4, 2000

C. Manwart, S. Torquato, R. Hilfer

Physical Review E 62, 893 (2000)
https://doi.org/10.1103/PhysRevE.62.893

submitted on
Friday, February 4, 2000

A simulated annealing algorithm is employed to generate a stochastic model for a Berea sandstone and a Fontainebleau sandstone, with each a prescribed two-point probability function, lineal-path function, and “pore size” distribution function, respectively. We find that the temperature decrease of the annealing has to be rather quick to yield isotropic and percolating configurations. A comparison of simple morphological quantities indicates good agreement between the reconstructions and the original sandstones. Also, the mean survival time of a random walker in the pore space is reproduced with good accuracy. However, a more detailed investigation by means of local porosity theory shows that there may be significant differences of the geometrical connectivity between the reconstructed and the experimental samples.

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Tags reconstruction models, sand stone

image analysis Porous Media

Quantitative Analysis of Experimental and Synthetic Microstructures for Sedimentary Rock

Post author By R Hilfer
Post date April 17, 1999

B. Biswal, C. Manwart, R. Hilfer, S. Bakke, P.E. Øren

Physica A 273, 452 (1999)
https://doi.org/10.1016/S0378-4371(99)00248-4

submitted on
Monday, May 17, 1999

A quantitative comparison between the experimental microstructure of a sedimentary rock and three theoretical models for the same rock is presented. The microstructure of the rock sample (Fontainebleau sandstone) was obtained by microtomography. Two of the models are stochastic models based on correlation function reconstruction, and one model is based on sedimentation, compaction and diagenesis combined with input from petrographic analysis. The porosity of all models closely match that of the experimental sample and two models have also the same two point correlation function as the experimental sample. We compute quantitative differences and similarities between the various microstructures by a method based on local porosity theory. Differences are found in the degree of anisotropy, and in fluctuations of porosity and connectivity. The stochastic models differ strongly from the real sandstone in their connectivity properties, and hence need further refinement when used to model transport.

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Tags reconstruction models, sediments

Porous Media Simulations

Reconstruction of Random Media Using Monte Carlo Methods

Post author By R Hilfer
Post date September 8, 1998

C. Manwart, R. Hilfer

Physical Review E 59, 5596 (1999)
https://doi.org/10.1103/PhysRevE.59.5596

submitted on
Tuesday, September 8, 1998

A simulated annealing algorithm is applied to the reconstruction of two-dimensional porous media with prescribed correlation functions. The experimental correlation function of an isotropic sample of Fontainebleau sandstone and a synthetic correlation function with damped oscillations are used in the reconstructions. To reduce the numerical effort we follow a proposal suggesting the evaluation of the correlation functions only along certain directions. The results show that this simplification yields significantly different microstructures as compared to a full evaluation of the correlation function. In particular, we find that the simplified reconstruction method introduces an artificial anisotropy that is originally not present.

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Tags reconstruction models, sand stone, sediments

image analysis Porous Media Simulations

Microstructure Analysis of Reconstructed Porous Media

Post author By R Hilfer
Post date July 15, 1998

B. Biswal, R. Hilfer

Physica A 266, 307 (1999)
https://doi.org/10.1016/S0378-4371(98)00607-4

submitted on
Wednesday, July 15, 1998

We compare the quantitative microstructural properties of Berea Sandstone with stochastic reconstructions of the same sandstone. The comparison is based on local porosity theory. The reconstructions employ Fourier space filtering of Gaussian random fields and match the average porosity and two-point correlation function of the experimental model. Connectivity properties of the stochastic models differ significantly from the experimental model. Reconstruction models with different levels of coarse graining also show different average local connectivity.

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Tags reconstruction models