Incorporating hysteresis in a multi-phase multi-component NAPL modelling framework; a multi-component LNAPL gasoline example

Lari, Kaveh Sookhak; Davis, Gordon B.; Johnston, Colin D.

doi:10.1016/j.advwatres.2016.07.012

Cited by 33 publications

(10 citation statements)

References 25 publications

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“…The capillary pressure-saturation-relative permeability model was later amended by [17] to include residual LNAPL. [22] also incorporated hysteresis in capillary pressure-saturation-relative permeability relations into a multiphase, multicomponent numerical simulator to predict subsurface LNAPL migration. If investigators want to use predictive models similar to [8] and obtain realistic results, then they will need to employ parameters describing capillary-pressure relations reflecting the current conditions in the subsurface.…”

Section: Discussionmentioning

confidence: 99%

Testing an Analytical Model for Predicting Subsurface LNAPL Distributions from Current and Historic Fluid Levels in Monitoring Wells: A Preliminary Test Considering Hysteresis

Lenhard

Rayner

García-Rincón

2019

Water

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Knowledge of subsurface light nonaqueous phase liquid (LNAPL) saturation is important for developing a conceptual model and a plan for addressing LNAPL contaminated sites. Investigators commonly predict LNAPL mobility and potential recoverability using information such as LNAPL physical properties, subsurface characteristics, and LNAPL saturations. Several models exist that estimate the LNAPL specific volume and transmissivity from fluid levels in monitoring wells. Commonly, investigators use main drainage capillary pressure–saturation relations because they are more frequently measured and available in the literature. However, main drainage capillary pressure–saturation relations may not reflect field conditions due to capillary pressure–saturation hysteresis. In this paper, we conduct a preliminary test of a recent analytical model that predicts subsurface LNAPL saturations, specific volume, and transmissivity against data measured at a LNAPL contaminated site. We call our test preliminary because we compare only measured and predicted vertical LNAPL saturations at a single site. Our results show there is better agreement between measured and predicted LNAPL saturations when imbibition capillary pressure–saturation relations are employed versus main drainage capillary pressure–saturation relations. Although further testing of the model for different conditions and sites is warranted, the preliminary test of the model was positive when consideration was given to capillary pressure–saturation hysteresis, which suggests the model can yield reasonable predictions that can help develop and update conceptual site models for addressing subsurface LNAPL contamination. Parameters describing capillary pressure–saturation relations need to reflect conditions existing at the time when the fluid levels in a well are measured.

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Section: Discussionmentioning

confidence: 99%

Testing an Analytical Model for Predicting Subsurface LNAPL Distributions from Current and Historic Fluid Levels in Monitoring Wells: A Preliminary Test Considering Hysteresis

Lenhard

Rayner

García-Rincón

2019

Water

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“…A nonpartitioning (NP, i.e., nonsoluble nonvolatile) LNAPL with a higher viscosity (HV) equal to 0.9 cP and two LNAPLs with lower viscosity (LV) equal to 0.45 cP. One is also a NP LNAPL, while the other has the average solubility and vapor pressure of fresh gasoline (here called a partitioning [P] LNAPL; Sookhak Lari, Davis, & Johnston, ; Sookhak Lari, Johnston, & Davis, ). The abbreviations and properties used for different LNAPLs are summarized in Table .…”

Section: Drivers For An Optimization Toolmentioning

confidence: 99%

“…The code is a parallel‐processing version of TMVOC, which is a member of the TOUGH2 family of simulators (Pruess & Battistelli, ). The FORTRAN source code of the model has been enhanced previously to include new features (Sookhak Lari, Davis, & Johnston, ). The model simulator has been recently applied to simulate various LNAPL multiphase recovery technologies and to determine operational endpoints to these technologies under various site conditions (Sookhak Lari, Johnston, et al, ; Sookhak Lari, Rayner, & Davis, ).…”

Section: Drivers For An Optimization Toolmentioning

confidence: 99%

Toward Optimizing LNAPL Remediation

Lari

Rayner

Davis

2019

Water Resources Research

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Optimizing the remediation of light nonaqueous phase liquids (LNAPLs) to achieve an acceptable endpoint status for a site is not trivial. Recently, Sookhak Lari, Johnston, et al. (2018, https://doi.org/10.1016/j.jhazmat.2017.006), Sookhak Lari, Rayner, and Davis (2018, https://doi.org/10.1016/j.jenvman.2018.07.041) conducted three-dimensional multiphase, multicomponent simulations to address LNAPL remediation endpoints for a single recovery well. However, optimized LNAPL remediation for multiple wells is not addressed in the literature. In the first part of this paper, we establish a matrix of 10 simulation scenarios to show the sensitivity of the remedial endpoint (i.e., what is feasibly achieved) to several parameters including viscosity and partitioning attributes of the LNAPL, heterogeneity of the formation, and the location and number of the recovery wells. While this addresses the variability of LNAPL removal from the subsurface and is valuable in its own right, it does not address the optimal removal of LNAPL. We address this in the second part of the paper by linking a genetic algorithm to TMVOC-MP to allow, for example, the assessment of the optimal number and location of LNAPL recovery wells in a field-scale problem. Using supercomputing facilities and within 49 genetic algorithm generations, each including 150 members, highly optimized answers to different objective functions were obtained. For the first time, such a multiphase, multicomponent optimization tool promises the possibility of optimizing LNAPL remediation at field scale to achieve practicable endpoint conditions, within computational affordability.

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“…The source code for the multiphase, multicomponent TMVOC software, which is a FORTRAN 77 integral finite‐difference simulator, is commercially available containing subroutines with simple constitutive relations for fluid relative permeabilities, saturations, and capillary heads. The Commonwealth Scientific and Industrial Research Organization (CSIRO), an Australian Government corporate entity, purchased, modified, and used the multiphase, multicomponent TMVOC to investigate subsurface contamination issues with LNAPL (Sookhak Lari et al , ; Lekmine et al ). To conduct numerical simulations of LNAPL saturation distributions to test the assumption in the Lenhard et al () model, we modified subroutines in TMVOC to incorporate equivalent relative permeability‐saturation‐capillary head constitutive relations in Lenhard et al ().…”

Section: Numerical Model Modificationmentioning

confidence: 99%

Evaluating an Analytical Model to Predict Subsurface LNAPL Distributions and Transmissivity from Current and Historic Fluid Levels in Groundwater Wells: Comparing Results to Numerical Simulations

Lenhard¹,

Lari²,

Rayner³

et al. 2018

Groundwater Monitoring Rem

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This column reviews the general features of PHT3D Version 2, a reactive multicomponent transport model that couples the geochemical modeling software PHREEQC-2 (Parkhurst and Appelo 1999) with three-dimensional groundwater flow and transport simulators MODFLOW-2000 and MT3DMS (Zheng and Wang 1999). The original version of PHT3D was developed by Henning Prommer and Version 2 by Henning Prommer and Vincent Post (Prommer and Post 2010). More detailed information about PHT3D is available at the website http://www.pht3d.org.The review was conducted separately by two reviewers. This column is presented in two parts. PART I by C.A.J. Appelo IntroductionPHT3D is a computer code for general reactive transport calculations, coupling MODFLOW/MT3DMS for transport and PHREEQC for chemical reactions. It was developed by Henning Prommer in the 1990s and has been applied by him and his coworkers to various groundwater problems of practical interest. The resulting publications (http://www.pht3d.org/pht3d public.html) show an impressive applicability of the code and illustrate the underlying understanding of quite complicated interactions (e.g., Prommer and Stuyfzand 2005; Prommer et al. 2008 Prommer et al. , 2009). In the original version, transport is calculated during a time step, an input file is written for PHREEQC for calculating reactions such as ion exchange and precipitation or dissolution of minerals, and these steps are repeated for subsequent time steps until finished. This loose coupling has the advantage that updates of the master programs can be installed without much effort. A disadvantage is that the calculation of the chemical reactions needs to be initialized time and again for each cell in the model, which adds another time-consuming step to calculations that are already computer-intensive. Another disadvantage is that surface complexation reactions need to be calculated first using the water composition from the previous time step and then reacted with the changed water concentrations. This procedure was not implemented in the original version of PHT3D, and surface complexation reactions could not be calculated.Prommer and Post recently released the second version of PHT3D that resolves the shortcomings and works very well. The improvement is owing firstly to the implementation of total-variation-diminishing (TVD) scheme that MT3DMS uses for calculating advective and dispersive transport (Zheng and Wang 1999). Secondly, it is because PHREEQC is now being used for storing the chemical data of the model, including the chemical activities and the composition of surface complexes from the previous time step. In addition, the procedure to transport total oxygen and hydrogen has been adapted from PHAST (PHAST is the 3D reactive transport model developed by Parkhurst et al. 2004, based on HST3D and PHREEQC). This enables the user to obtain the redox state of the solution without having to transport individual redox concentrations of the elements (e.g., C being distributed over carbon-dioxide, C(4), and methane, C...

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Incorporating hysteresis in a multi-phase multi-component NAPL modelling framework; a multi-component LNAPL gasoline example

Cited by 33 publications

References 25 publications

Testing an Analytical Model for Predicting Subsurface LNAPL Distributions from Current and Historic Fluid Levels in Monitoring Wells: A Preliminary Test Considering Hysteresis

Testing an Analytical Model for Predicting Subsurface LNAPL Distributions from Current and Historic Fluid Levels in Monitoring Wells: A Preliminary Test Considering Hysteresis

Toward Optimizing LNAPL Remediation

Evaluating an Analytical Model to Predict Subsurface LNAPL Distributions and Transmissivity from Current and Historic Fluid Levels in Groundwater Wells: Comparing Results to Numerical Simulations

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