### Abstract

Flow to wells in nonuniform geologic formations is of central interest to hydrogeologists and petroleum engineers. There are, however, very few mathematical analyses of such flow. We present analytical expressions for leading statistical moments of vertically averaged hydraulic head and flux under steady-state flow to a well that pumps water from a bounded, randomly heterogeneous aquifer. Like in the widely used Thiem equation, we prescribe a constant pumping rate deterministically at the well and a constant head at a circular outer boundary of radius L. We model the natural logarithm Y = In T of aquifer transmissivity T as a statistically homogeneous random field with a Gaussian spatial correlation function. Our solution is based on exact nonlocal moment equations for multidimensional steady state flow in bounded, randomly heterogeneous porous media. Perturbation of these nonlocal equations leads to a system of local recursive moment equations that we solve analytically to second order in the standard deviation of Y. In contrast to most stochastic analyses of flow, which require that log transmissivity be multivariate Gaussian, our solution is free of any distributional assumptions. It yields expected values of head and flux, and the variance-covariance of these quantities, as functions of distance from the well. It also yields an apparent transmissivity, T_{a}, defined as the negative ratio between expected flux and head gradient at any radial distance. The solution is supported by numerical Monte Carlo simulations, which demonstrate that it is applicable to strongly heterogeneous aquifers, characterized by large values of log transmissivity variance. The two-dimensional nature of our solution renders it useful for relatively thin aquifers in which vertical heterogeneity tends to be of minor concern relative to that in the horizontal plane. It also applies to thicker aquifers when information about their vertical heterogeneity is lacking, as is commonly the case when measurements of head and flow rate are done in wells that penetrate much of the aquifer thickness. Potential uses include the analysis of pumping tests and tracer test conducted in such wells, the statistical delineation of their respective capture zones, and the analysis of contaminant transport toward fully penetrating wells.

Original language | English (US) |
---|---|

Pages (from-to) | 139-193 |

Number of pages | 55 |

Journal | Transport in Porous Media |

Volume | 45 |

Issue number | 1 |

DOIs | |

State | Published - Oct 2001 |

### Fingerprint

### Keywords

- Apparent transmissivity
- Flux covariance
- Head covariance
- Nonhomogeneous porous media
- Nonlocal moment equations
- Numerical Monte Carlo analysis
- Perturbation analysis
- Random velocity fields
- Well flow predictors

### ASJC Scopus subject areas

- Chemical Engineering(all)
- Catalysis

### Cite this

*Transport in Porous Media*,

*45*(1), 139-193. https://doi.org/10.1023/A:1011880602668

**Radial flow in a bounded randomly heterogeneous aquifer.** / Riva, M.; Guadagnini, A.; Neuman, Shlomo P; Franzetti, S.

Research output: Contribution to journal › Article

*Transport in Porous Media*, vol. 45, no. 1, pp. 139-193. https://doi.org/10.1023/A:1011880602668

}

TY - JOUR

T1 - Radial flow in a bounded randomly heterogeneous aquifer

AU - Riva, M.

AU - Guadagnini, A.

AU - Neuman, Shlomo P

AU - Franzetti, S.

PY - 2001/10

Y1 - 2001/10

N2 - Flow to wells in nonuniform geologic formations is of central interest to hydrogeologists and petroleum engineers. There are, however, very few mathematical analyses of such flow. We present analytical expressions for leading statistical moments of vertically averaged hydraulic head and flux under steady-state flow to a well that pumps water from a bounded, randomly heterogeneous aquifer. Like in the widely used Thiem equation, we prescribe a constant pumping rate deterministically at the well and a constant head at a circular outer boundary of radius L. We model the natural logarithm Y = In T of aquifer transmissivity T as a statistically homogeneous random field with a Gaussian spatial correlation function. Our solution is based on exact nonlocal moment equations for multidimensional steady state flow in bounded, randomly heterogeneous porous media. Perturbation of these nonlocal equations leads to a system of local recursive moment equations that we solve analytically to second order in the standard deviation of Y. In contrast to most stochastic analyses of flow, which require that log transmissivity be multivariate Gaussian, our solution is free of any distributional assumptions. It yields expected values of head and flux, and the variance-covariance of these quantities, as functions of distance from the well. It also yields an apparent transmissivity, Ta, defined as the negative ratio between expected flux and head gradient at any radial distance. The solution is supported by numerical Monte Carlo simulations, which demonstrate that it is applicable to strongly heterogeneous aquifers, characterized by large values of log transmissivity variance. The two-dimensional nature of our solution renders it useful for relatively thin aquifers in which vertical heterogeneity tends to be of minor concern relative to that in the horizontal plane. It also applies to thicker aquifers when information about their vertical heterogeneity is lacking, as is commonly the case when measurements of head and flow rate are done in wells that penetrate much of the aquifer thickness. Potential uses include the analysis of pumping tests and tracer test conducted in such wells, the statistical delineation of their respective capture zones, and the analysis of contaminant transport toward fully penetrating wells.

AB - Flow to wells in nonuniform geologic formations is of central interest to hydrogeologists and petroleum engineers. There are, however, very few mathematical analyses of such flow. We present analytical expressions for leading statistical moments of vertically averaged hydraulic head and flux under steady-state flow to a well that pumps water from a bounded, randomly heterogeneous aquifer. Like in the widely used Thiem equation, we prescribe a constant pumping rate deterministically at the well and a constant head at a circular outer boundary of radius L. We model the natural logarithm Y = In T of aquifer transmissivity T as a statistically homogeneous random field with a Gaussian spatial correlation function. Our solution is based on exact nonlocal moment equations for multidimensional steady state flow in bounded, randomly heterogeneous porous media. Perturbation of these nonlocal equations leads to a system of local recursive moment equations that we solve analytically to second order in the standard deviation of Y. In contrast to most stochastic analyses of flow, which require that log transmissivity be multivariate Gaussian, our solution is free of any distributional assumptions. It yields expected values of head and flux, and the variance-covariance of these quantities, as functions of distance from the well. It also yields an apparent transmissivity, Ta, defined as the negative ratio between expected flux and head gradient at any radial distance. The solution is supported by numerical Monte Carlo simulations, which demonstrate that it is applicable to strongly heterogeneous aquifers, characterized by large values of log transmissivity variance. The two-dimensional nature of our solution renders it useful for relatively thin aquifers in which vertical heterogeneity tends to be of minor concern relative to that in the horizontal plane. It also applies to thicker aquifers when information about their vertical heterogeneity is lacking, as is commonly the case when measurements of head and flow rate are done in wells that penetrate much of the aquifer thickness. Potential uses include the analysis of pumping tests and tracer test conducted in such wells, the statistical delineation of their respective capture zones, and the analysis of contaminant transport toward fully penetrating wells.

KW - Apparent transmissivity

KW - Flux covariance

KW - Head covariance

KW - Nonhomogeneous porous media

KW - Nonlocal moment equations

KW - Numerical Monte Carlo analysis

KW - Perturbation analysis

KW - Random velocity fields

KW - Well flow predictors

UR - http://www.scopus.com/inward/record.url?scp=0035477119&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035477119&partnerID=8YFLogxK

U2 - 10.1023/A:1011880602668

DO - 10.1023/A:1011880602668

M3 - Article

AN - SCOPUS:0035477119

VL - 45

SP - 139

EP - 193

JO - Transport in Porous Media

JF - Transport in Porous Media

SN - 0169-3913

IS - 1

ER -