Electric potential source localization reveals a borehole leak during hydraulic fracturing

Abstract

A laboratory experiment was performed to see if passively recorded electric signals can be inverted to retrieve the position of fluid leakages along a well during an attempt to hydraulically fracture a porous block in the laboratory. The cubic block was instrumented with 32 nonpolarizing sintered Ag/AgCl electrodes. During the test, several events were detected corresponding to fluid leakoff along the seal of the well. Each event showed a quick burst in the electric field followed by an exponentialtype relaxation of the potential distribution over time. The occurrence of these "electric" events was always correlated with a burst in the acoustic emissions and a change in the fluid pressure. These self-potential data were inverted in two steps: (1) using a deterministic least-square algorithm with focusing to retrieve the position of the source current density in the block for a given snapshot in the electric potential distribution and (2) using a genetic algorithm to refine the position of the source current density on a denser grid. The results of the inversion were found to be in excellent agreement with the position of the well where the hydraulic test was performed and with the localization of the acoustic emissions in the vicinity of this well. This experiment indicates that passively recorded electric signals can be used to monitor fluid flow along the well during leakages, and perhaps monitor fluid flow for numerous applications involving hydromechanical disturbances.

Induced polarization response of porous media with metallic particles — Part 3: A new approach to time-domain induced polarization tomography

“…This is, however, not done in this paper because the secondary voltage data present a very low level of noise. The codes we are using have been validated and benchmarked in several of our recent papers dealing with self-potential tomography (Haas et al, 2013;Rittgers et al, 2013). …”

“…We also reference the voltages to a temporal reference as traditionally done in self-potential surveys (Jardani et al, 2008;Haas et al, 2013;Revil et al, 2015c). We pick the measurements at .…”

Transport Properties through Partially Saturated Charged Membranes and Geophysical Approaches

“…In this case, the source of current is due to the existence of source current densities existing at the synapses between the neurons and corresponding to the opening of ionic channels. Recent examples of the use of self-potential methods including algorithms to perform the inverse problem can be found in Rittgers et al (2013) (for the monitoring of corrosion) and Haas et al (2013) (for the monitoring of hydromechanical disturbances). These two papers contain a description for the equipment and the electrodes that can be used for this monitoring purpose.…”

A hybrid optimization scheme for self‐potential measurements due to multiple sheet‐like bodies in arbitrary 2D resistivity distributions

“…In addition, a grid‐independent based inversion can estimate the position of a dipole accurately without the usage of dense grids or dense sub‐grids within a sparse main grid such as the methodology proposed by Haas et al . ().…”

“…The fact that the source can be placed in a continuous 2D space allows for an accurate estimation of the coordinates of the dipole without using two‐step procedures that employ a dense sub‐grid inside a main sparse one (Haas et al . ). Subsequently, a dumbed non‐linear least‐squares method (Marquadt ) is used in order to estimate the properties of the sheet‐like body subject to a 2D resistivity distribution.…”