scholarly journals New Model of Reactive Transport in Single-Well Injection-Withdrawal Test with Aquitard Effect

2020 ◽  
Author(s):  
Quanrong Wang ◽  
Wenguang Shi ◽  
Hongbin Zhan
Keyword(s):  
Reactive Transport ◽  
Molecular Diffusion ◽  
Breakthrough Curves ◽  
Advective Transport ◽  
New Model ◽  
Single Well ◽  
Radial Dispersion ◽  
Injection Phase ◽  
Extraction Phase

Abstract. The model of single-well injection-withdrawal (SWIW) test has been widely used to investigate reactive radial dispersion in remediation or parameter estimation of the in situ aquifers. Previous analytical solutions only focused on a completely isolated aquifer for the SWIW test, excluding any influence of aquitards bounding the tested aquifer. This simplification might be questionable in field applications when test durations are relatively long, because solute transport in or out of the bounding aquitards is inevitable due to molecular diffusion and cross-formational advective transport. Here, a new SWIW model is developed in an aquifer-aquitard system, and the analytical solution in the Laplace domain is derived. Four phases of the test are included: the injection phase, the chaser phase, the rest phase and the extraction phase. The Green's function method is employed for the solution in the extraction phase. As the permeability of aquitard is much smaller than the permeability of the aquifer, the flow is assumed to be perpendicular to the aquitard, thus only vertical dispersive and advective transports are considered for aquitard. The validity of this treatment is tested by a numerical solution. The sensitivity analysis demonstrates that the influence of vertical flow velocity and porosity in the aquitards, and radial dispersion of the aquifer is more sensitive to the SWIW test than other parameters. In the injection phase, the larger radial dispersivity of the aquifer could result in the smaller values of breakthrough curves (BTCs), while greater values of BTCs of the chaser and rest phases. In the extraction phase, it could lead to the smaller peak values of BTCs. The new model of this study performs better than previous studies excluding the aquitard effect for interpreting data of the field SWIW test.

scholarly journals New model of reactive transport in a single-well push–pull test with aquitard effect and wellbore storage

2020 ◽  
Vol 24 (8) ◽  
pp. 3983-4000
Author(s):  
Quanrong Wang ◽  
Junxia Wang ◽  
Hongbin Zhan ◽  
Wenguang Shi
Keyword(s):  
Reactive Transport ◽  
Molecular Diffusion ◽  
Breakthrough Curves ◽  
Advective Transport ◽  
New Model ◽  
Wellbore Storage ◽  
Single Well ◽  
Radial Dispersion ◽  
Injection Phase ◽  
Extraction Phase

Abstract. The model of single-well push–pull (SWPP) test has been widely used to investigate reactive radial dispersion in remediation or parameter estimation of in situ aquifers. Previous analytical solutions only focused on a completely isolated aquifer for the SWPP test, excluding any influence of aquitards bounding the tested aquifer, and ignored the wellbore storage of the chaser and rest phases in the SWPP test. Such simplification might be questionable in field applications when test durations are relatively long because solute transport in or out of the bounding aquitards is inevitable due to molecular diffusion and cross-formational advective transport. Here, a new SWPP model is developed in an aquifer–aquitard system with wellbore storage, and the analytical solution in the Laplace domain is derived. Four phases of the test are included: the injection phase, the chaser phase, the rest phase and the extraction phase. As the permeability of the aquitard is much smaller than the permeability of the aquifer, the flow is assumed to be perpendicular to the aquitard; thus only vertical dispersive and advective transports are considered for the aquitard. The validity of this treatment is tested against results grounded in numerical simulations. The global sensitivity analysis indicates that the results of the SWPP test are largely sensitive (i.e., influenced by) to the parameters of porosity and radial dispersion of the aquifer, whereas the influence of the aquitard on results could not be ignored. In the injection phase, the larger radial dispersivity of the aquifer could result in the smaller values of breakthrough curves (BTCs), while there are greater BTC values in the chaser and rest phases. In the extraction phase, it could lead to the smaller peak values of BTCs. The new model of this study is a generalization of several previous studies, and it performs better than previous studies ignoring the aquitard effect and wellbore storage for interpreting data of the field SWPP test reported by Yang et al. (2014).

scholarly journals Push-pull tests for estimating effective porosity: expanded analytical solution and in situ application

2017 ◽  
Vol 26 (2) ◽  
pp. 381-393 ◽  
Author(s):  
Charles J. Paradis ◽  
Larry D. McKay ◽  
Edmund Perfect ◽  
Jonathan D. Istok ◽  
Terry C. Hazen
Keyword(s):  
Analytical Solution ◽  
Center Of Mass ◽  
Unconfined Aquifer ◽  
Effective Porosity ◽  
Pull Test ◽  
True Value ◽  
Single Well ◽  
Pull Tests ◽  
Injection Phase

Abstract The analytical solution describing the one-dimensional displacement of the center of mass of a tracer during an injection, drift, and extraction test (push-pull test) was expanded to account for displacement during the injection phase. The solution was expanded to improve the in situ estimation of effective porosity. The truncated equation assumed displacement during the injection phase was negligible, which may theoretically lead to an underestimation of the true value of effective porosity. To experimentally compare the expanded and truncated equations, single-well push-pull tests were conducted across six test wells located in a shallow, unconfined aquifer comprised of unconsolidated and heterogeneous silty and clayey fill materials. The push-pull tests were conducted by injection of bromide tracer, followed by a non-pumping period, and subsequent extraction of groundwater. The values of effective porosity from the expanded equation (0.6–5.0%) were substantially greater than from the truncated equation (0.1–1.3%). The expanded and truncated equations were compared to data from previous push-pull studies in the literature and demonstrated that displacement during the injection phase may or may not be negligible, depending on the aquifer properties and the push-pull test parameters. The results presented here also demonstrated the spatial variability of effective porosity within a relatively small study site can be substantial, and the error-propagated uncertainty of effective porosity can be mitigated to a reasonable level (< ± 0.5%). The tests presented here are also the first that the authors are aware of that estimate, in situ, the effective porosity of fine-grained fill material.

Lagrangian models of reactive transport in heterogeneous porous media with uncertain properties

2011 ◽  
Vol 468 (2140) ◽  
pp. 1154-1174 ◽  
Author(s):  
G. Severino ◽  
D. M. Tartakovsky ◽  
G. Srinivasan ◽  
H. Viswanathan
Keyword(s):  
Porous Media ◽  
Reactive Transport ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Parametric Uncertainty ◽  
Bimolecular Reaction ◽  
Breakthrough Curves ◽  
Heterogeneous Porous Media ◽  
Advective Transport ◽  
Transport Parameters

We consider multi-component reactive transport in heterogeneous porous media with uncertain hydraulic and chemical properties. This parametric uncertainty is quantified by treating relevant flow and transport parameters as random fields, which renders the governing equations stochastic. We adopt a stochastic Lagrangian framework to replace a three-dimensional advection–reaction transport equation with a one-dimensional equation for solute travel times. We derive approximate expressions for breakthrough curves and their temporal moments. To illustrate our general theory, we consider advective transport of dissolved species undergoing an irreversible bimolecular reaction.

scholarly journals Reactive transport with wellbore storages in a single-well push–pull test

2019 ◽  
Vol 23 (4) ◽  
pp. 2207-2223 ◽  
Author(s):  
Quanrong Wang ◽  
Hongbin Zhan
Keyword(s):  
Solute Transport ◽  
Reactive Transport ◽  
Breakthrough Curves ◽  
Field Application ◽  
Linear Functions ◽  
Hydraulic Diffusivity ◽  
Wellbore Storage ◽  
Nonlinear Reactions ◽  
Single Well ◽  
Robin Condition

Abstract. Using the single-well push–pull (SWPP) test to determine the in situ biogeochemical reaction kinetics, a chase phase and a rest phase were recommended to increase the duration of reaction, besides the injection and extraction phases. In this study, we presented multi-species reactive models of the four-phase SWPP test considering the wellbore storages for both groundwater flow and solute transport and a finite aquifer hydraulic diffusivity, which were ignored in previous studies. The models of the wellbore storage for solute transport were proposed based on the mass balance, and the sensitivity analysis and uniqueness analysis were employed to investigate the assumptions used in previous studies on the parameter estimation. The results showed that ignoring it might produce great errors in the SWPP test. In the injection and chase phases, the influence of the wellbore storage increased with the decreasing aquifer hydraulic diffusivity. The peak values of the breakthrough curves (BTCs) increased with the increasing aquifer hydraulic diffusivity in the extraction phase, and the arrival time of the peak value became shorter with a greater aquifer hydraulic diffusivity. Meanwhile, the Robin condition performed well at the rest phase only when the chase concentration was zero and the solute in the injection phase was completely flushed out of the borehole into the aquifer. The Danckwerts condition was better than the Robin condition even when the chase concentration was not zero. The reaction parameters could be determined by directly best fitting the observed data when the nonlinear reactions were described by piece-wise linear functions, while such an approach might not work if one attempted to use nonlinear functions to describe such nonlinear reactions. The field application demonstrated that the new model of this study performed well in interpreting BTCs of a SWPP test.

scholarly journals Coupling Flow, Heat, and Reactive Transport Modeling to Reproduce In Situ Redox Potential Evolution: Application to an Infiltration Pond

2020 ◽  
Vol 54 (19) ◽  
pp. 12092-12101
Author(s):  
Paula Rodríguez-Escales ◽  
Carme Barba ◽  
Xavier Sanchez-Vila ◽  
Diederik Jacques ◽  
Albert Folch
Keyword(s):  
Redox Potential ◽  
Reactive Transport ◽  
Transport Modeling ◽  
Reactive Transport Modeling ◽  
Flow Heat

scholarly journals In situ investigations and reactive transport modelling of cement paste/argillite interactions in a saturated context and outside an excavated disturbed zone

2013 ◽  
Vol 31 ◽  
pp. 94-108 ◽  
Author(s):  
Danièle Bartier ◽  
Isabelle Techer ◽  
Alexandre Dauzères ◽  
Philippe Boulvais ◽  
Marie-Madeleine Blanc-Valleron ◽  
...  
Keyword(s):  
Cement Paste ◽  
Reactive Transport ◽  
Reactive Transport Modelling ◽  
Transport Modelling ◽  
Disturbed Zone

scholarly journals Long residence times of rapidly decomposable soil organic matter: application of a multi-phase, multi-component, and vertically-resolved model (TOUGHREACTv1) to soil carbon dynamics

2014 ◽  
Vol 7 (1) ◽  
pp. 815-870 ◽  
Author(s):  
W. J. Riley ◽  
F. M. Maggi ◽  
M. Kleber ◽  
M. S. Torn ◽  
J. Y. Tang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Reactive Transport ◽  
Lignin Content ◽  
Sensitivity Analyses ◽  
Rooting Depth ◽  
Carbon Substrate ◽  
Advective Transport ◽  
Turnover Rates ◽  
Multi Phase

Abstract. Accurate representation of soil organic matter (SOM) dynamics in Earth System Models is critical for future climate prediction, yet large uncertainties exist regarding how, and to what extent, the suite of proposed relevant mechanisms should be included. To investigate how various mechanisms interact to influence SOM storage and dynamics, we developed a SOM reaction network integrated in a one-dimensional, multi-phase, and multi-component reactive transport solver. The model includes representations of bacterial and fungal activity, multiple archetypal polymeric and monomeric carbon substrate groups, aqueous chemistry, aqueous advection and diffusion, gaseous diffusion, and adsorption (and protection) and desorption from the soil mineral phase. The model predictions reasonably matched observed depth-resolved SOM and dissolved organic carbon (DOC) stocks in grassland ecosystems as well as lignin content and fungi to aerobic bacteria ratios. We performed a suite of sensitivity analyses under equilibrium and dynamic conditions to examine the role of dynamic sorption, microbial assimilation rates, and carbon inputs. To our knowledge, observations do not exist to fully test such a complicated model structure or to test the hypotheses used to explain observations of substantial storage of very old SOM below the rooting depth. Nevertheless, we demonstrated that a reasonable combination of sorption parameters, microbial biomass and necromass dynamics, and advective transport can match observations without resorting to an arbitrary depth-dependent decline in SOM turnover rates, as is often done. We conclude that, contrary to assertions derived from existing turnover time based model formulations, observed carbon content and δ14C vertical profiles are consistent with a representation of SOM dynamics consisting of (1) carbon compounds without designated intrinsic turnover times, (2) vertical aqueous transport, and (3) dynamic protection on mineral surfaces.

Sign in / Sign up

Export Citation Format

Share Document