Gas-Coning by a Horizontal Well

Papatzacos, Paul

doi:10.3997/2214-4609.201411344

Cited by 4 publications

(5 citation statements)

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“…This assumption is not very restrictive in our case because most horizontal and slanted wells used in environmental applications have quite low pumping rates. Discussion of nonlinear effects is beyond the scope of this paper and can be found elsewhere [e.g., Polubarinova‐Kochina , 1962; Dagan , 1967a, 1967b, 1968; Papatzakos , 1992; Gjerde and Tyvand , 1992; MacDonald and Kitanidis , 1993].…”

Section: Flow To a Point Sinkmentioning

confidence: 99%

Groundwater flow to a horizontal or slanted well in an unconfined aquifer

Zhan

Zlotnik

2002

Water Resources Research

124

123

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[1] New semianalytical solutions for evaluation of the drawdown near horizontal and slanted wells with finite length screens in unconfined aquifers are presented. These fully three-dimensional solutions consider instantaneous drainage or delayed yield and aquifer anisotropy. As a basis, solution for the drawdown created by a point source in a uniform anisotropic unconfined aquifer is derived in Laplace domain. Using superposition, the point source solution is extended to the cases of the horizontal and slanted wells. The previous solutions for vertical wells can be described as a special case of the new solutions. Numerical Laplace inversion allows effective evaluation of the drawdown in real time. Examples illustrate the effects of well geometry and the aquifer parameters on drawdown. Results can be used to generate type curves from observations in piezometers and partially or fully penetrating observation wells. The proposed solutions and software are useful for the parameter identification, design of remediation systems, drainage, and mine dewatering.

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Section: Flow To a Point Sinkmentioning

confidence: 99%

Groundwater flow to a horizontal or slanted well in an unconfined aquifer

Zhan

Zlotnik

2002

Water Resources Research

124

123

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“…When qD < 0.4, the fast Fourier transform with convergence acceleration (FFT-CA) is used. For qD>O.4, it is possible to close the iteration procedure 8 and explicitly determine…”

Section: (10) 144mentioning

confidence: 99%

Cone Breakthrough Time for Horizontal Wells

Papatzacos

Herring²,

Martinsen³

et al. 1991

SPE Reservoir Engineering

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Recovery from an oil zone underlying a gas cap, overlying an aquifer, or sandwiched between gas and water can be improved by repressing the coning problem through horizontal-well drainage. Literature methods to predict coning behavior are limited to steady-state flow conditions and determination of the critical rate. The results in this paper are based on new semianalytical solutions for time development of a gas or water cone and of simultaneous gas and water cones in an anisotropic infinite reservoir with a horizontal well placed in the oil column. The solutions are derived by a moving-boundary method with gravity equilibrium assumed in the cones. For the gas-cone case, the semianalytical results are presented as a single dimensionless curve (time to breakthrough vs. rate) and as a simple analytical expression for dimensionless rates > l!J. For the simultaneous gas-and water-cone case, the results are given in two dimensionless sets of curves: one for the optimum vertical well placement and one for the corresponding time to breakthrough, both as functions of rate with the density contrast as a parameter. The validity of the results has been extensively tested by a general numerical simulation model. Sample calculations with reservoir data from the Troll field and comparison with test data from the Helder field demonstrate how the theory can be used to estimate the time to cone breakthrough and its sensitivity to the uncertainties in reservoir parameters.

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“…If this is not the case, the relevant model will be that of a constant flux. This situation has been considered recently by Papatzacos [1992], in the limit as a • 0, b • oo, and d • o•. In Appendix A we give asymptotic formulas in excellent agreement with Papatzacos' theory.…”

Section: Discussionmentioning

confidence: 54%

Transient free‐surface groundwater flow due to an array of circular drainage ditches

Gjerde¹,

Tyvand²

1992

Water Resources Research

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The present paper is a numerical study of a transient free‐surface flow into an array of circular drainage ditches in a porous medium. By the boundary integral equation method and a semi‐Lagrangian description of motion, the groundwater table is tracked as a function of time. Primarily, we consider the case of atmospheric pressure along the ditch contour. An analytical small‐time expansion is presented in an appendix. In contrast to the case of constant flux into a sink (Papatzacos, 1989), there is no cusp formation at the free surface. The flux into a ditch is approximately a linearly decreasing function of time. We also include a second version of the boundary condition at the ditch; parts of its contour are impermeable.

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Gas-Coning by a Horizontal Well

Cited by 4 publications

References 0 publications

Groundwater flow to a horizontal or slanted well in an unconfined aquifer

Groundwater flow to a horizontal or slanted well in an unconfined aquifer

Cone Breakthrough Time for Horizontal Wells

Transient free‐surface groundwater flow due to an array of circular drainage ditches

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