HR: 0830h
AN: H21D-0856    [PDF]
TI: Seawater Upconing Under a Pumping Horizontal Well in a Confined Coastal Aquifer
AU: * Sun, D
EM: d0s8863@geo.tamu.edu
AF: Texas A&M University, Department of Geology and Geophysics,, College Station, TX 77843 United States
AU: Zhan, H
EM: zhan@geo.tamu.edu
AF: Texas A&M University, Department of Geology and Geophysics,, College Station, TX 77843 United States
AB: Coastal margins are one of the nation­_s greatest natural resources and economic assets. Due to increasing concentration of human settlements and economic activities in the coastal margins, it is critical to find better technologies of managing the coastal groundwater resources. Coastal aquifers always have saline water underneath the fresh water. This phenomenon substantially limits the groundwater pumping rates using traditional vertical wells because of the upconing of the fresh/saline water interfaces and the potential of sea water intrusion. With the advancement of horizontal well technology, we propose to use long-screen (kilometers) horizontal wells in coastal aquifers to increase groundwater supply and prevent sea water intrusion into those wells. In this study, we have developed two mathematical models to predict the equilibrium location of upconed sharp interfaces due to pumping horizontal wells based on the linear model of Muskat (1982) and the non-linear model of Dagan and Bear (1968) which described the upcoming due to a partially penetrating vertical pumping well. The horizontal well solution is obtained by integrating the point sink solution along the horizontal well axis. The linear solution based on Muskat­_s model (1982) is acquired by neglecting the pressure field variation caused by the change of the fresh/saline water interface, while the nonlinear solution includes that variation. The computed interface profiles based on these two models are compared with those of vertical wells. The critical pumping rate is calculated and the sensitivity of the interface profile on aquifer anisotropy, horizontal well depth, and horizontal well length is tested. References: G. Dagan and J. Bear, Solving the problem of local interface upcoming in a coastal aquifer by the method of small perturbations, J. Hydraulic Research, 6, 15-44, 1968. Muskat, M, The flow of homogeneous Fluids Through Porous Media, International Human Resources Development Corporation, Boston, 763 PP, 1982.
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2003 Fall Meeting