Radial groundwater flow to a finite diameter well in a leaky confined aquifer with a finite‐thickness skin

Abstract

Abstract:A mathematical model that describes the drawdown due to constant pumpage from a finite radius well in a two-zone leaky confined aquifer system is presented. The aquifer system is overlain by an aquitard and underlain by an impermeable formation. A skin zone of constant thickness exists around the wellbore. A general solution to a two-zone leaky confined aquifer system in Laplace domain is developed and inverted numerically to the time-domain solution using the modified Crump (1976) algorithm. The results show that the drawdown distribution is significantly influenced by the properties and thickness of the skin zone and aquitard. The sensitivity analyses of parameters of the aquifer and aquitard are performed to illustrate their effects on drawdowns in a two-zone leaky confined aquifer system. For the negative-skin case, the drawdown is very sensitive to the relative change in the formation transmissivity. For the positive-skin case, the drawdown is also sensitive to the relative changes in the skin thickness, and both the skin and formation transmissivities over the entire pumping period and the well radius and formation storage coefficient at early pumping time.

Non-Darcian effect on slug test in a leaky confined aquifer

“…However, Eq. (23) may not work well when the unit and/or the order of magnitude of the parameters are different, and then the normalized sensitivity analysis was proposed as follows (Kabala, 2001;Yang and Yeh, 2009) …”

Reactive transport with wellbore storages in a single-well push–pull test

“…McCuen 1985proposed a sensitivity model of a dependent variable, which was normalized as (Kabala, 2001;Yang and Yeh, 2009)…”

“…Actually, the above-mentioned assumptions used in the analytical and semi-analytical solutions can be relaxed in the numerical models, such as MODFLOW/MT3DMS (Harbaugh et al, 2000;Zheng and Wang, 1999), FEFLOW (Diersch, 2014), SUTRA (Voss, 1984), and STOMP (Nichols et al, 1997). Huang et al (2010), Sun (2016), Haggerty et al (1998), and Schroth and Istok (2006), respectively, employed such four software packages to carry out numerical simulations of SWPP tests, mainly involving advection, dispersion and first-order reaction.…”

Recent advances in modeling of well hydraulics

“…Their solution took into account the effects of finite well radius and the water stored inside the wellbore, which were neglected in the Theis equation. Theoretical models are developed for incorporating the effect of finite well radius [151,152] and both effects of finite well radius and wellbore storage into models [34,153]. Other issues of large-diameter wells such as seepage face, an application of discrete kernel approach and well function approximations are widely discussed in the literatures.…”