Flow to a horizontal well in an aquitard–aquifer system

Sun, Dongmin; Zhan, Hongbin

doi:10.1016/j.jhydrol.2005.08.008

Cited by 54 publications

(44 citation statements)

References 34 publications

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“…However, the use of HDDWs in the Freshmaker case may make thin aquifers viable for abstraction/storage, since a single, high-capacity well is feasible. Approriate design of the HDDW (length, diameter, pumping rates, amongst others) is however crucial to attain a uniform distribution of the abstraction along the HDDW screen (Sun and Zhan 2006;Wang et al 2014). At the Freshmaker trial, this was ensured by the relatively limited length of the HDDWs (70 m) and confirmed by the observed lowering of the freshwater-saltwater interface along full length the wells; & Saline seepage in deep polders: ASR-coastal may freshen the diffusive seepage component sourced by shallow groundwater in the upper aquifer, but is less effective in counteracting seepage of deeper, saline groundwater via boils, which can be the largest salt contributor in polder areas ).…”

Section: Broader Evaluation Of the Efficiency Of Subsurface Water Tecmentioning

confidence: 99%

How Subsurface Water Technologies (SWT) can Provide Robust, Effective, and Cost-Efficient Solutions for Freshwater Management in Coastal Zones

Zuurbier

Raat

Paalman

et al. 2016

Water Resour Manage

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Freshwater resources in coastal zones are limited while demands are high, resulting in problems like seasonal water shortage, overexploitation of freshwater aquifers, and seawater intrusion. Three subsurface water technologies (SWT) that can provide robust, effective, and cost-efficient solutions to manage freshwater resources in the subsurface are evaluated using groundwater modelling and validation at field-scale: (1) ASR-coastal to store freshwater surpluses in confined brackish-saline aquifers for recovery in times of demand, (2) the Freshkeeper to counteract salinization of well fields by interception and desalination of upconing brackish groundwater, and (3) the Freshmaker to combine ASR and Freshkeeper to enlarge the volume of natural freshwater lenses for later abstraction. The evaluation indicates that SWT can be used in various hydrogeological settings for various hydrogeological problems like seawater intrusion, upconing, and bubble drift during ASR and have significant economic benefits. Although only sporadically applied to date, we foresee that SWT will stimulate (cost-)efficient and sustainable exploitation of various freshwater sources (like groundwater, rainwater, treated waste water, surface water) in coastal zones. Prolonged SWT testing in the current pilots, replication of SWT in other areas worldwide, and the development of technical and non-technical support tools are required to facilitate potential end-users in investment decision making and SWT implementation.

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Section: Broader Evaluation Of the Efficiency Of Subsurface Water Tecmentioning

confidence: 99%

How Subsurface Water Technologies (SWT) can Provide Robust, Effective, and Cost-Efficient Solutions for Freshwater Management in Coastal Zones

Zuurbier

Raat

Paalman

et al. 2016

Water Resour Manage

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“…Temporal drawdown distributions subject to the aquitard storage effect were compared with those without that effect. Sun and Zhan (2006) derived a semianalytical solution of drawdown due to pumping at a horizontal well in a leaky aquifer. A transient 1-D flow equation describing the vertical flow across the aquitard was considered.…”

Section: C-s Huang Et Al: Approximate Analysis Of Three-dimensionamentioning

confidence: 99%

Approximate analysis of three-dimensional groundwater flow toward a radial collector well in a finite-extent unconfined aquifer

Huang

Chen

Yeh

2016

Hydrol. Earth Syst. Sci.

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Abstract. This study develops a three-dimensional (3-D) mathematical model for describing transient hydraulic head distributions due to pumping at a radial collector well (RCW) in a rectangular confined or unconfined aquifer bounded by two parallel streams and no-flow boundaries. The streams with low-permeability streambeds fully penetrate the aquifer. The governing equation with a point-sink term is employed. A first-order free surface equation delineating the water table decline induced by the well is considered. Robin boundary conditions are adopted to describe fluxes across the streambeds. The head solution for the point sink is derived by applying the methods of finite integral transform and Laplace transform. The head solution for a RCW is obtained by integrating the point-sink solution along the laterals of the RCW and then dividing the integration result by the sum of lateral lengths. On the basis of Darcy's law and head distributions along the streams, the solution for the stream depletion rate (SDR) can also be developed. With the aid of the head and SDR solutions, the sensitivity analysis can then be performed to explore the response of the hydraulic head to the change in a specific parameter such as the horizontal and vertical hydraulic conductivities, streambed permeability, specific storage, specific yield, lateral length, and well depth. Spatial head distributions subject to the anisotropy of aquifer hydraulic conductivities are analyzed. A quantitative criterion is provided to identify whether groundwater flow at a specific region is 3-D or 2-D without the vertical component. In addition, another criterion is also given to allow for the neglect of vertical flow effect on SDR. Conventional 2-D flow models can be used to provide accurate head and SDR predictions if satisfying these two criteria.

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“…However, by keeping the discharge rate below a critical or maximum allowable value, the saline water will not enter the well (Bower et al 1999). The maximum allowable discharge rate should expectedly be more in horizontal wells compared to vertical wells under the same conditions due to their relatively broader and shallower depression cone (Zhan et al 2001;Sun and Zhan 2006).…”

Section: Introductionmentioning

confidence: 99%

Steady critical discharge rates from vertical and horizontal wells in fresh–saline aquifers with sharp interfaces

et al. 2016

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In this study, the critical (or maximum) discharge rates before saline water enters a well were determined for vertical and horizontal wells in a freshwater aquifer which is separated from a static saline aquifer by a sharp interface. Flow around the well was solved by integration of a point sink solution along the well axis, and both the critical discharge rate and critical interface rise were determined through a comparison of the heads and vertical gradients at the saline-fresh water interface. The rates were determined for vertical and horizontal wells with various lengths and depths for different aquifer salinities. Results were generalized by drawing dimensionless type curves. The results showed that the dimensionless total critical discharge rates are higher for the longer horizontal wells and longer vertical wells with a certain bottom depth, and they almost linearly decrease with well depth at rates of 0.7-0.9. For the dimensionless well length of 0.2, the dimensionless total discharge rate of a horizontal well is about 0.1 more than that of a vertical well with the same length and well-top depth. Also, the critical discharge rates per unit length of well are inversely proportional to well length and remarkably higher for shallower wells. Additionally, the critical pumping rate is proportional to the salinity difference of the aquifers. These results were confirmed by comparison to existing solutions for vertical wells with dimensionless lengths of 0.2, 0.5 and 0.6, and for critical interface rises in the range of 0.75-0.9.

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Flow to a horizontal well in an aquitard–aquifer system

Cited by 54 publications

References 34 publications

How Subsurface Water Technologies (SWT) can Provide Robust, Effective, and Cost-Efficient Solutions for Freshwater Management in Coastal Zones

How Subsurface Water Technologies (SWT) can Provide Robust, Effective, and Cost-Efficient Solutions for Freshwater Management in Coastal Zones

Approximate analysis of three-dimensional groundwater flow toward a radial collector well in a finite-extent unconfined aquifer

Steady critical discharge rates from vertical and horizontal wells in fresh–saline aquifers with sharp interfaces

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