Solutions for Three Aquifer Tests Involving Partially Penetrating Well
|關鍵字:||含水層試驗;定水頭試驗;定流量試驗;微水試驗;部分貫穿井;井膚層.;aquifer tests;constant head test;constant flux test;slug test;partially penetrating well;wellboreskin.|
The aquifer tests including constant head test, constant flux test, and slug test are usually used to investigate the hydrogeological properties of aquifers. Most analytical solutions related to the aquifer tests are based on the assumption that the pumping wells fully penetrate the aquifers. The flow in the aquifer is horizontal when assuming that the well is fully penetrated, and the resulting govern equation can be easily solved by conventional integral transform techniques. However, if the well partially penetrates the aquifer, the flow system will contain both horizontal and vertical flows. It is difficult to solve the problem with a partially penetrating well by the conventional methods. In the past, such problems were solved by simplifying the well boundary condition. However, these solutions will give significant errors in predicting the distribution of the hydraulic head and flow velocity near the wellbore. This study plans to solve the problem with a partially penetrating well for the aquifer tests such as constant head, constant flux and slug tests. In the first year, the new analytical solution for the partially penetrating well in a constant head test will be derived. In the second year, we will derive the solutions for constant-flux test and slug test which are also performed in a partially penetrating well. In the last year, we will further consider the wellbore skin, produced mainly by well drilling process, and derive the analytical solution for the constant head test. Those aquifer test solutions can be used to (1) describe the temporal and spatial distribution of hydraulic head in the aquifer system, (2) verify the numerical models, and (3) estimated the hydrogeological parameters if coupling with an optimization approach.
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