The flow of water in a charged porous material is the source of in the relaxation phase following the shutdown of the an electrical field called the streaming potential. The origin of this pump. Despite the fact that the problem is treated here coupling is associated with the drag of the excess of charge contained for a thin tank (two-dimensional approximation), all the in the vicinity of the pore–water interface by the pore fluid flow. In this results obtained in this paper can easily be transposed paper, we present a sandbox experiment to study this “hydroelectric” to the three-dimensional case corresponding to the apcoupling in the case of a pumping test. A relatively thin Plexiglas plication of the method in the field. tank was filled with homogeneous sand and then infiltrated with tapwater. A pumping test experiment was performed in the middle THEORY of the tank with a peristaltic pump. The resulting electrical potential distribution was measured passively at the top of the tank with a net- In this section, we present a model that will be used later work of 27 nonpolarizable electrodes related to a digital multichan- to interpret the sandbox experiment. The porous material is nel multimeter plus an additional electrode used as a reference. A assumed to be isotropic with respect to all the material properdetectable electrical field was produced at the ground surface and ties introduced below. The total electrical density J (A m2) analyzed with analytical solutions of the coupled hydroelectric prob- is the sum of a conductive current given by Ohm’s Law and lem. After the shutdown of the pump, the electrical potential and the a driving current density JS. The latest is associated with the piezometric level exhibit similar relaxation times in the vicinity of the pore fluid pressure field (e.g., Titov et al., 2000, 2002; Revil pumping well. This means that the electrical potential measured at et al., 2003, and references therein). This yields the following the ground surface can be used to track the flow of the groundwater constitutive equation: and possibly to invert the distribution of the hydraulic transmissivity of the ground.
A sandbox experiment of self-potential signals associated with a pumping test
RIZZO E;
2004
Abstract
The flow of water in a charged porous material is the source of in the relaxation phase following the shutdown of the an electrical field called the streaming potential. The origin of this pump. Despite the fact that the problem is treated here coupling is associated with the drag of the excess of charge contained for a thin tank (two-dimensional approximation), all the in the vicinity of the pore–water interface by the pore fluid flow. In this results obtained in this paper can easily be transposed paper, we present a sandbox experiment to study this “hydroelectric” to the three-dimensional case corresponding to the apcoupling in the case of a pumping test. A relatively thin Plexiglas plication of the method in the field. tank was filled with homogeneous sand and then infiltrated with tapwater. A pumping test experiment was performed in the middle THEORY of the tank with a peristaltic pump. The resulting electrical potential distribution was measured passively at the top of the tank with a net- In this section, we present a model that will be used later work of 27 nonpolarizable electrodes related to a digital multichan- to interpret the sandbox experiment. The porous material is nel multimeter plus an additional electrode used as a reference. A assumed to be isotropic with respect to all the material properdetectable electrical field was produced at the ground surface and ties introduced below. The total electrical density J (A m2) analyzed with analytical solutions of the coupled hydroelectric prob- is the sum of a conductive current given by Ohm’s Law and lem. After the shutdown of the pump, the electrical potential and the a driving current density JS. The latest is associated with the piezometric level exhibit similar relaxation times in the vicinity of the pore fluid pressure field (e.g., Titov et al., 2000, 2002; Revil pumping well. This means that the electrical potential measured at et al., 2003, and references therein). This yields the following the ground surface can be used to track the flow of the groundwater constitutive equation: and possibly to invert the distribution of the hydraulic transmissivity of the ground.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
