Porous Dissolution Reactors

Fogler, H. Scott; Rege, S.D.

doi:10.1080/00986448608911747

Cited by 14 publications

(12 citation statements)

References 14 publications

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“…This pore-throat diameter is the threshold reactivity diameter defined by Swift and Fogler (1977), which represents the pore-throat size above which the dissolution has the largest effect. Previous studies have also shown that chemical dissolution primarily influences larger pores Rege, 1986, Rege andFogler, 1989). The MICP results are consistent with visual observations of the 3D tomograms indicating considerable enlarging of oomoldic pores.…”

Section: D Geometry Of the Dissolution Patternsupporting

confidence: 88%

Micro-tomographic Characterization of Dissolution-induced Local Porosity Changes including Fines Migration in Carbonate Rock

2012

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The microstructure of carbonate rocks experiences substantial changes under reactive processes, in particular chemical dissolution and deposition including dissolution-released fines migration occurring during acidizing. A better understanding of such changes at the pore scale and their influences on rock properties is of great value for the effective design and implementation of reactive processes in carbonate reservoirs. In this work, we demonstrate the use of X-ray micro-computed tomography (μ-CT) to quantitatively investigate the local porosity changes in a meso/microporous carbonate core sample during chemical dissolution. A reactive flooding experiment in a core sample by a non-acidic solution is designed such that changes in pore space from before to after the reactant injection could be imaged in exactly the same locations using μ-CT at resolution of less than 5μm. A methodology based on three-phase segmentation and 2D intensity histograms of images is used to quantify distributions of the evolution of each image voxel. This technique allows the incorporation of microporosity into the calculation of the evolution regions including the migration of fines in order to accurately quantify the evolution scenarios. The µ-CT images reveal a quasi-uniform dissolution pattern and allow characterizing the accompanying migration of fines within the core sample. 3D pore networks are derived from the image data, which quantify changes in network structure and the pore geometry. 2D histograms of image intensity derived from the pre-and post-dissolution images quantitatively show how macro and micropores are enlarged by dissolution close to the inlet while deposition of fines mainly occurs in pores far from the inlet boundary. These results can explain why permeability of the sample initially decreases and then increases as injection time increases. Based on the spatially resolved voxel evolution scenarios, pore surface area between each region is computed. This allows calculation of local distribution of reactive surface area which in turn will assist in the prediction of local reaction rates in reactive flow simulators.

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Section: D Geometry Of the Dissolution Patternsupporting

confidence: 88%

Micro-tomographic Characterization of Dissolution-induced Local Porosity Changes including Fines Migration in Carbonate Rock

2012

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“…Several models for flow and reaction in porous media exist in the literature. A comprehensive review of these and other models is presented in Fogler and Rege (1985). Primary among these models are those by Lund and Fogler (1976) and by Walsh et al (1984).…”

Section: Summary Of Previous Modelsmentioning

confidence: 99%

Competition among flow, dissolution, and precipitation in porous media

Rege

Fogler

1989

AIChE Journal

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A theoretical and experimental study has been carried out on flow, dissolution, and precipitation in porous media. Flow experiments were performed on linear carbonate cores using acidic ferric chloride solutions. Dissolution of the carbonate by the acid causes an increase in the solution pH, thereby precipitating ferric hydroxide. This precipitate plugs up the pore throats in the medium and increases the resistance to fluid flow. Fluctuations in the permeability ratio were observed during core flood experiments, confirming the competition between channel formation due to dissolution and pore plugging due to precipitation. The evolution of the pore structure was characterized by Wood's metal castings.A network model has also been developed to describe flow and reaction in porous media. The model was used to simulate the ferric chloride system, and pressure oscillations predicted by the model show identical trends to those observed experimentally. Additionally, the evolution of pores in the network were graphically represented.

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“…As a result, this research represents yet another study of mass transfer with chemical reaction, a subject that has enriched the literature of chemical engineering (Astarita, 1967;Astarita et al, 1983;Fogler and Rege, 1986). In the vast majority of past cases, the chemical reactions are first order.…”

Section: Discussionmentioning

confidence: 92%

Theories of precipitation induced by dissolution

1988

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When a porous solid is placed in acid, the solid dissolves at its surface. However, the same solid can precipitate or dissolve in pores inside the solid. The internal precipitation is a consequence of a nonlinear solubility product amplified by fast chemical kinetics. The internal dissolution can be enhanced by unequal diffusiQn coefficients. Both precipitation and dissolution can occur simultaneously but in different regions, mimicking the patterns of mineral found in teeth.

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Porous Dissolution Reactors

Cited by 14 publications

References 14 publications

Micro-tomographic Characterization of Dissolution-induced Local Porosity Changes including Fines Migration in Carbonate Rock

Micro-tomographic Characterization of Dissolution-induced Local Porosity Changes including Fines Migration in Carbonate Rock

Competition among flow, dissolution, and precipitation in porous media

Theories of precipitation induced by dissolution

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