MODFLOW–USG version 1: An unstructured grid version of MODFLOW for simulating groundwater flow and tightly coupled processes using a control volume finite-difference formulation

Panday, Sorab; Langevin, Christian D.; Niswonger, Richard G.; Ibaraki, Motomu; Hughes, Joseph D.

doi:10.3133/tm6a45

Cited by 134 publications

(127 citation statements)

References 26 publications

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“…26; Email: mlux@mol.hu János Szanyi, Tivadar M. Tóth: University of Szeged, H-6722, Szeged, Egyetem u. [2][3][4][5][6] necessarily in the same plane [1]. This suggests that the variations of multi-lateral well patterns are only limited by technology and imagination.…”

Section: Introductionmentioning

confidence: 90%

“…Cai et al differentiated fishbone configurations depending on whether the branches are situated on one or both sides of the main wellbore and also considered the symmetry of the lateral branches [6]. However we applied symmetric configurations where branches on the two sides of the main wellbore are symmetrically and evenly distributed ( Figure 1).…”

Section: Methodsmentioning

confidence: 99%

“…However we present the optimization results for both configurations: 100 For USG modelling we used Visual Modflow Flex software (which uses Voronoi polygons for unstructured grids, therefore the cells are prisms with bases of Voronoi polygons, as the model domain is vertically structured) [6], while for SG we applied Processing Modflow (using square grids). Regarding the model domain we constructed a simple, "cake-type" model with 5 separately homogeneous, isotropic layers on an area of 1000 m × 1000 m. The upperand lowermost layers have aquitard characteristics (hydraulic conductivity: Kx = Ky = Kz = 10 −6 m·s −1 , total porosity: ϕ = 0.05, effective porosity: ϕ e = 0.02, specific storage: Ss = 10 −5 m −1 , specific yield: Sy = 0.02) with 3 aquifers between them.…”

Section: Methodsmentioning

confidence: 99%

“…The conceptual model is the same as described above. Since we equiangularly distributed the radial branches, branch number (2,4,6,8,10) We evaluated fishbone wells along the same principle as radially distributed multi-lateral wells but branch number and branch angle had to be evaluated separately.…”

Section: Methodsmentioning

confidence: 99%

“…In the present work, we applied unstructured grids (USG) to model multi-lateral wells using the MODFLOW-USG code which simulates groundwater flow using a generalized control volume finite-difference approach, which allows grids other than orthogonal structured grids (SG) [6]. This offers a solution for orientation problems and also allows for sufficiently small cell size around the laterals without overly increasing the number of cells in the whole model domain.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation and optimization of multi-lateral wells using MODFLOW unstructured grids

2016

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Multi-lateral wells have been increasingly used in recent years by different industries including oil-and gas industry along with coal bed methane-and water production. The common purpose of these wells is to achieve a higher production rate per well. More and more sophisticated well patterns and geometries can be implemented in practice which calls for improved modelling techniques. Complicated well geometries and small lateral diameters require high resolution models in the vicinity of the wells. With structured finite difference grids this can only be achieved by unnecessary refinements even far away from the wellbores. However the model may still suffer from orientation problems if laterals do not coincide with the rows or columns of the rectangular mesh. In the present work, we applied unstructured grids to model multi-lateral wells and compared the results to structured models. We used the MODFLOW-USG code, which simulates groundwater flow using a generalized control volume finite-difference approach, allowing grids other than orthogonal structured grids to be applied. This offers a solution for orientation and resolution problems. The second part of the paper aims to optimize multi-lateral well geometry by evaluating the effect of length, angle and number of laterals.

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Section: Introductionmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation and optimization of multi-lateral wells using MODFLOW unstructured grids

2016

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Locally conservative groundwater flow in the continuous Galerkin method using 3‐D prismatic patches

Zhao

Lin

et al. 2016

Water Resources Research

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A new procedure has been developed to improve the velocity field computed by the continuous Galerkin finite element method (CG). It enables extending the postprocessing algorithm proposed by Cordes and Kinzelbach (1992) to three‐dimensional (3‐D) models by using prismatic patches for saturated groundwater flow. This approach leverages a dual mesh to preserve local mass conservation and provides interpolated velocities based on consistent fluxes. To develop this 3‐D approach, a triangular conservative patch is introduced by computing not only advection fluxes, but also vertical infiltrations, storage changes, and other sink or source terms. This triangular patch is then used to develop a prismatic patch, which consists of subprisms in two layers. By dividing a single two‐layer patch into two separate one‐layer patches, two dimensional (2‐D) algorithms can be applied to compute velocities. As a consequence, each subelement is able to preserve local mass conservation. A hypothetical 3‐D model is used to evaluate the precision of streamlines and flow rates generated by this approach and the FEFLOW simulation program.

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Generation of complex karstic conduit networks with a hydrochemical model

Rooij

Graham

2017

Water Resources Research

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In this paper, we present a hydrochemical model that can be used to generate plausible karstic conduit networks that honor what is known about geology, hydrology, and topography of a karst system. To make the model applicable to a range of natural karst systems, we introduce a flexible and physically realistic flow boundary condition along the land surface. Moreover, whereas comparable existing speleogenesis models use an explicit reactive‐transport scheme, we propose an implicit reactive‐transport scheme to permit a coarser spatial discretization of the conduit cells. An application to a real karst system illustrates that the model can generate a realistic karstic network that reproduces observed hydrologic behavior in terms of current spring flow rates, regional hydraulic head field as well as average groundwater residence times. Our model provides a useful tool to generate ensembles of possible karstic conduit networks that may be used within a stochastic framework to analyze flow and transport prediction uncertainty associated with a lack of knowledge about network geometry.

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MODFLOW–USG version 1: An unstructured grid version of MODFLOW for simulating groundwater flow and tightly coupled processes using a control volume finite-difference formulation

Cited by 134 publications

References 26 publications

Evaluation and optimization of multi-lateral wells using MODFLOW unstructured grids

Evaluation and optimization of multi-lateral wells using MODFLOW unstructured grids

Locally conservative groundwater flow in the continuous Galerkin method using 3‐D prismatic patches

Generation of complex karstic conduit networks with a hydrochemical model

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