关键词: 非完整井, 越流承压含水层, 侧向边界, 解析解, 非稳定流

Abstract: When there is invariant/uninfluenced pumping drawdown and waterproof curtain at a distance r =rb from the pumping well, the aquifer system is laterally finite in extend (termed finite aquifer) and rb is termed ‘finite radius’. A practical calculation model of transient flow to a partially penetrating well in a typical aquitard-confined aquifer of finite extent is developed. Also, the model considers the effect of well radius and wellbore storage. The drawdown solution is obtained by the Laplace transform coupled with separation of variables, and inverted into the time-domain solution utilizing the Stehfest method. Moreover, the obtained solutions can reduce to some available solutions and are further validated by comparison with other solutions. Finally, the effect of the lateral boundary and well configuration on pumped aquifer drawdown behaviors are analyzed based on the proposed analytical solution. The results show that the influence of the lateral boundary is obvious during the late pumping time, the drawdown of the finite aquifer system is larger than that for Case 1 (constant head boundary at r = rb) and much smaller than that for Case 2 (no-flux boundary at r = rb). A smaller finite radius rb results in a larger error between the finite aquifer system (Case 1/Case 2) and the infinite aquifer system. The impact of the well configurations occurs at the whole pumping stage for different cases, and the drawdown at the top of the pumped aquifer becomes smaller with the increase of the length and location of the well screen.

Key words: partially penetrating well, leaky confined aquifer, lateral (radial) boundary, analytical solution, non-steady flow