Transient flowmeter test: semi-analytic crossflow model

Kabala, Z. J.; El-Sayegh, H. K.

doi:10.1016/s0309-1708(01)00013-6

Cited by 7 publications

(4 citation statements)

References 74 publications

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“…Where boreholes were intersected by more than two layers, constraining the inflow concentration proved difficult where the flowing section was supplied partially by water from another flowing borehole section rather than mainly from the formation. More complex aquifer systems, including multiple permeable layers that are potentially cross‐connected, could be modeled using more sophisticated approaches to the interpretation of borehole flow data, which take into account interlayer flow and wellbore storage, such as those described by Williams and Paillet (1992) and Kabala and El‐Sayegh (2002). The accuracy of the transmissivity and storativity values determined from such approaches is always likely to be less than those from pumping tests conducted on separate permeable layers via screened wells; however, the observation well flow method has the advantage of requiring much less sophisticated well construction and no prior knowledge of permeable layer thicknesses and depths.…”

Section: Discussionmentioning

confidence: 99%

“…However, hydraulic test programs benefit greatly if preliminary knowledge is available concerning depths and connectivity of the permeable horizons to be tested (e.g., fracture zones). Such information can be obtained from flowmeter logging and from borehole dilution testing (Drost et al 1968;Freeze and Cherry 1979;Pedler et al 1990Pedler et al , 1992Tsang et al 1990;Palmer 1993;Wilson et al 1999;Paillet 2000;Kabala and El-Sayegh 2002;Williams and Paillet 2002;Brainerd and Robbins 2004;Hiscock 2005;Le Borgne et al 2006a, 2006b.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of a Multilayer Aquifer Using Open Well Dilution Tests

West¹,

Odling

2006

Groundwater

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An approach to characterization of multilayer aquifer systems using open well borehole dilution is described. The approach involves measuring observation well flow velocities while a nearby extraction well is pumped by introducing a saline tracer into observation wells and collecting dilution vs. depth profiles. Inspection of tracer profile evolution allows discrete permeable layers within the aquifer to be identified. Dilution profiles for well sections between permeable layers are then converted into vertical borehole flow velocities and their evolution, using an analytic solution to the advection-dispersion equation applied to borehole flow. The dilution approach is potentially able to measure much smaller flow velocities that would be detectable using flowmeters. Vertical flow velocity data from the observation wells are then matched to those generated using a hydraulic model of the aquifer system, "shorted" by the observation wells, to yield the hydraulic properties of the constituent layers. Observation well flow monitoring of pumping tests represents a cost-effective alternative or preliminary approach to pump testing each layer of a multilayer aquifer system separately using straddle packers or screened wells and requires no prior knowledge of permeable layer depths and thicknesses. The modification described here, of using tracer dilution rather than flowmeter logging to obtain well flow velocities, allows the approach to be extended to greater well separations, thus characterizing a larger volume of the aquifer. An example of the application of this approach to a multilayer Chalk Aquifer in Yorkshire, Northeast England, is presented.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of a Multilayer Aquifer Using Open Well Dilution Tests

West¹,

Odling

2006

Groundwater

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“…Alternatively, double-layer numerical models are used to consider more complex configurations, including vertical crossflow between adjacent porous layers or skin effect with a homogeneous skin zone located around the well [31][32][33]. Heterogeneous skin factors, wellbore storage, and transient pumping rate are considered separately in different studies such as the semi-analytical multi-aquifer models developed in [34,35] and the methods formulated in [14,26]. These three features describe phenomena occurring in the pumping well and its vicinity that are important for the interpretation of pumping tests.…”

Section: Introductionmentioning

confidence: 99%

Models and Interpretation Methods for Single-Hole Flowmeter Experiments

Lods

Roubinet

2023

Water

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Subsurface and groundwater flow characterization is of great importance for various environmental applications, such as the dispersion of contaminants and their remediation. For single-hole flowmeter measurements, key characteristics, such as wellbore storage, skin factor heterogeneities, and variable pumping and aquifer flow rates, have a strong impact on the system characterization, whereas they are not fully considered in existing models and interpretation methods. In this study, we develop a new semi-analytical solution that considers all these characteristics in a physics-based consistent manner. We also present two new interpretation methods, the Double Flowmeter Test with Transient Flow rate (DFTTF) and the Transient Flow rate Flowmeter Test (TFFT), for interpreting data collected during single and multiple pumping tests, respectively. These solution and methods are used as follows. (i) The impact of wellbore storage, transient pumping rate, and property heterogeneities on the interpretation of data collected during single pumping tests are studied over 49 two-aquifer cases. (ii) The effect of the skin factor heterogeneity on transmissivity and storativity estimates, as well as the variability range of the (non-unique) corresponding solutions, are analyzed for the interpretation of multiple-pumping experiments. The results presented in this work show the importance of the various properties and processes that are considered, and the need for the new models and methods that are provided.

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“…The flux along the well screen was non-uniform through an infinitesimal thin skin, and the flow was subject to the wellbore storage effect. Kabala and El-Sayegh (2002) presented a semi-analytical solution for the transient flowmeter test in a multilayered aquifer system where the radial flow was considered in each layer assuming no vertical flow component and uniform flux along the well screen. Predictions from the solution were compared with those from a numerical solution which relaxes those two assumptions.…”

Section: Introductionmentioning

confidence: 99%

Technical Note: Approximate solution of transient drawdown for constant-flux pumping at a partially penetrating well in a radial two-zone confined aquifer

Huang

Yang

Yeh

2015

Hydrol. Earth Syst. Sci.

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Abstract. An aquifer consisting of a skin zone and a formation zone is considered as a two-zone aquifer. Existing solutions for the problem of constant-flux pumping in a two-zone confined aquifer involve laborious calculation. This study develops a new approximate solution for the problem based on a mathematical model describing steady-state radial and vertical flows in a two-zone aquifer. Hydraulic parameters in these two zones can be different but are assumed homogeneous in each zone. A partially penetrating well may be treated as the Neumann condition with a known flux along the screened part and zero flux along the unscreened part. The aquifer domain is finite with an outer circle boundary treated as the Dirichlet condition. The steady-state drawdown solution of the model is derived by the finite Fourier cosine transform. Then, an approximate transient solution is developed by replacing the radius of the aquifer domain in the steady-state solution with an analytical expression for a dimensionless time-dependent radius of influence. The approximate solution is capable of predicting good temporal drawdown distributions over the whole pumping period except at the early stage. A quantitative criterion for the validity of neglecting the vertical flow due to a partially penetrating well is also provided. Conventional models considering radial flow without the vertical component for the constant-flux pumping have good accuracy if satisfying the criterion.

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Transient flowmeter test: semi-analytic crossflow model

Cited by 7 publications

References 74 publications

Characterization of a Multilayer Aquifer Using Open Well Dilution Tests

Characterization of a Multilayer Aquifer Using Open Well Dilution Tests

Models and Interpretation Methods for Single-Hole Flowmeter Experiments

Technical Note: Approximate solution of transient drawdown for constant-flux pumping at a partially penetrating well in a radial two-zone confined aquifer

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