A dual porosity model of high-pressure gas flow for geoenergy applications

This paper presents the development of a dual porosity numerical model of multiphase, multicomponent chemical–gas transport using a coupled thermal, hydraulic, chemical, and mechanical formulation. Appropriate relationships are used to describe the transport properties of nonideal, reactive gas mixtures at high pressure, enabling the study of geoenergy applications such as geological carbon sequestration. Theoretical descriptions of the key transport processes are based on a dual porosity approach considering the fracture network and porous matrix as distinct continua over the domain. Flow between the pore regions is handled using mass exchange terms and the model includes equilibrium and kinetically controlled chemical reactions. A numerical solution is obtained with a finite element and finite difference approach and verification of the model is pursued to build confidence in the accuracy of the implementation of the dual porosity governing equations. In the course of these tests, the time-splitting approach used to couple the transport, mass exchange, and chemical reaction modules is shown to have been successfully applied. It is claimed that the modelling platform developed provides an advanced tool for the study of high-pressure gas transport, storage, and displacement for geoenergy applications involving multiphase, multicomponent chemical–gas transport in dual porosity media, such as geological carbon sequestration.

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Einfluß der Strömungsform des Gases auf die chemischen Transportprozesse in Halogenglühlampen

Zeitschrift für Naturforschung A ◽

10.1515/zna-1974-1014 ◽

1974 ◽

Vol 29 (10) ◽

pp. 1471-1477

Author(s):

Gerhard M. Neumann

Keyword(s):

High Pressure ◽

Laminar Flow ◽

Gas Phase ◽

Flow Separation ◽

Gas Flow ◽

Chemical Transport ◽

Transport Processes ◽

Inert Gas ◽

Good Accord ◽

Incandescent Lamps

Abstract By raising the inert gas pressure and thus changing the type of gas flow chemical transport processes in tubular halogen incandescent lamps may be influenced. At medium pressures in the region of laminar flow separation of halogen and inert gas due to thermodiffusion occurs, the halogen cycle breaks down, and bulb blackening of the lamp is observed. At low and high pressure, where the streaming behaviour of the gas phase is dominated by diffusion or turbulence, separation of halogen and inert gas is overcome and the lamps stay clean. Observed pressures for changing from laminar to turbulent flow are 3.5 atm in xenon, 5.5 atm in krypton, and > 8 atm in argon in good accord with the well-known Reynolds' criterion.

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A Two-Dimensional Partitioning of Fracture–Matrix Flow in Fractured Reservoir Rock Using a Dual-Porosity Percolation Model

Energies ◽

10.3390/en14082209 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2209

Author(s):

Jinhui Liu ◽

Yuli Zhou ◽

Jianguo Chen

Keyword(s):

Fractured Rocks ◽

Gas Flow ◽

Gas Permeability ◽

Porous Matrix ◽

Percolation Model ◽

Dual Porosity ◽

Two Dimensional ◽

Fracture Density ◽

Matrix Permeability ◽

Matrix Flow

Fractures and micropores have varying contributions to the gas permeability of fractured reservoirs. The quantification of the contribution of fractures and micropores that form a dual-porosity system for gas permeability is critical when attempting to accurately evaluate gas production. However, due to insufficient knowledge of fracture–matrix flow partitioning in such dual-porosity systems, it is challenging for previous models to quantitatively characterize the fracture heterogeneity and accurately evaluate the gas flow and permeability in fractured rocks. In this study, we propose a dual-porosity percolation model to quantitatively investigate the contributions of fractures and matrix micropores towards the gas permeability of fractured rocks. Using percolation theory, we establish fracture networks with complex heterogeneity, which are characterized by various fracture densities and percolation probabilities within a porous matrix with various fracture/matrix permeability ratios. The compressible Navier–Stokes and Brinkman equations were adopted to describe the gas flow in the fractures and porous matrix, respectively. The simulation results indicate that the gas permeability of the dual-porosity system has an exponential relationship with the fracture density and matrix permeability. The contribution of fractures and matrix micropores toward gas permeability can be classified by establishing a two-dimensional partitioning of the fracture–matrix flow related to the fracture heterogeneity and fracture/matrix permeability ratio. The contribution of matrix micropores cannot be neglected if the fracture density is lower than a critical value.

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Gas transport in granular compacted bentonite: coupled hydro-mechanical interactions and microstructural features

E3S Web of Conferences ◽

10.1051/e3sconf/202019504008 ◽

2020 ◽

Vol 195 ◽

pp. 04008

Author(s):

Laura Gonzalez-Blanco ◽

Enrique Romero ◽

Paul Marschall

Keyword(s):

Gas Flow ◽

Gas Transport ◽

Initial Conditions ◽

Gas Injection ◽

Transport Processes ◽

Dry Density ◽

Gas Migration ◽

Micro Computed Tomography ◽

Saturation State ◽

Compacted Bentonite

The initial conditions (dry density and saturation state), the stress state and its history, and the deformation undergone during gas migration, affect the gas transport processes in granular compacted bentonite. Additionally, the sample microstructure set on compaction has a significant influence since gas tends to flow through preferential pathways. This experimental study intends to shed light on the gas transport and their coupled hydro-mechanical interactions with particular emphasis in the changes of the pore and pathway network. Controlled volume-rate gas injection followed by shut-off and dissipation stages have been performed under oedometer conditions. The microstructure of the samples has been characterised with three different techniques before and after the gas injection tests: Mercury Intrusion Porosimetry (MIP), Field-Emission Scanning Electron Microscopy (FESEM) and X-ray Micro-Computed Tomography (μ-CT). The results show a coupling of the deformational behaviour during the gas flow, revealing an expansion of the samples upon the development of gas pathways, which have been detected with the microstructural techniques. The opening of these pressure-dependent and connected pathways plays a major role in gas migration.

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Potential Pb+2 mobilization, transport, and sequestration in shallow aquifers impacted by multiphase CO2 leakage: a natural analogue study from the Virgin River Basin in Southwest Utah

Petroleum Geoscience ◽

10.1144/petgeo2020-109 ◽

2021 ◽

pp. petgeo2020-109

Author(s):

Michelle R. Plampin ◽

Madalyn S. Blondes ◽

Eric L. Sonnenthal ◽

William H. Craddock

Keyword(s):

Carbon Sequestration ◽

River Basin ◽

Numerical Models ◽

Co2 Storage ◽

Transport Processes ◽

Source Zone ◽

Natural Analogue ◽

Shallow Aquifers ◽

Geological Carbon Sequestration ◽

Virgin River

Geological carbon sequestration (GCS) is necessary to help meet emissions reduction goals, but groundwater contamination may occur if CO2 and/or brine were to leak out of deep storage formations into the shallow subsurface. For this study, a natural analogue was investigated: in the Virgin River Basin of southwest Utah, water with moderate salinity and high CO2 concentrations is leaking upward into shallow aquifers that contain heavy metal-bearing concretions. The aquifer system is comprised of the Navajo and Kayenta formations, which are pervasive across southern Utah and have been considered as a potential GCS injection unit where they are sufficiently deep. Numerical models of the site were constructed based on measured water chemistry and head distributions from previous studies. Simulations were used to improve understanding of the rate and distribution of the upwelling flow into the aquifers, and to assess the reactive transport processes that may occur if the upwelling fluids were to interact with a zone of iron oxide and other heavy metals, representing the concretions that are common in the area. Various mineralogies were tested, including one in which Pb+2 was adsorbed onto ferrihydrite, and another in which it was bound within a solid mixture of litharge (PbO) and hematite (Fe2O3). Results indicate that metal mobilization depends strongly on the source zone composition and that Pb+2 transport can be naturally attenuated by gas phase formation and carbonate mineral precipitation. These findings could be used to improve risk assessment and mitigation strategies at geological carbon sequestration sites.Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage

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