Seismoelectric wave propagation modeling for typical laboratory configurations: A numerical validation

Abstract

SUMMARYThe seismoelectric effect can be of importance for hydrocarbon exploration as it is complementary to conventional seismics. Besides enabling seismic resolution and electromagnetic sensitivity at the same time, the seismoelectric method can also provide us with additional, high-value information like porosity and permeability. However, very little is still understood of this complex physical phenomenon. Therefore, it is crucial to be able to perform numerical modeling experiments to carefully investigate the effect and the parameters that play a role. Over the last couple of years, several seismoelectric laboratory experiments have been carried out in an attempt to validate the underlying theory of the phenomenon and to better understand this complex physical phenomenon. We have recently extended our analytically based, numerical seismoelectric modeling code 'ESSEMOD' to be able to model seismoelectric wave propagation in arbitrarily layered Earth geometries with fluid / porous medium / (fluid) interfaces. In this way, we are capable of effectively simulating full seismoelectric wave propagation, i.e. all existing seismoelectric and electroseismic source-receiver combinations, in typical laboratory configurations. We present the underlying theory that is required for the extension towards arbitrary fluid / porous medium / (fluid) geometries and an effective way to incorporate this in a general seismoelectric layered Earth modeling code. We then validate the underlying global reflection scheme by comparing it with an independently developed layered Earth modeling code for purely electromagnetic fields. The results show a perfect match in both amplitude and phase, indicating that ESSEMOD is correctly modeling the electromagnetic parts of the seismoelectric wave propagation in horizontally layered media with fluid / porous medium / fluid transitions. We finalize with a seismoelectric reciprocal modeling experiment, proving that also the full seismoelectric wave propagation through fluid / porous medium transitions is modeled consistently.

Numerical Study of Frequency-dependent Seismoelectric Coupling in Partially-saturated Porous Media

“…As result, an electric field is produced [8,11,[25][26][27]29]. This phenomenon is referred to as "coseismic" electrical field.…”

Temperature dependence of the zeta potential in intact natural carbonates

“…SP measurements are widely used in geophysical monitoring of fluid flow in aquifers, hydrocarbon reservoirs, and geothermal fields [e.g., Corwin and Hoover, 1979;Morgan et al, 1989;Wurmstich and Morgan, 1994;Revil and Pezard, 1998;Darnet et al, 2003;Darnet et al, 2004;Jardani et al, 2008;Suski et al, 2008;Bolève et al, 2009], and the zeta potential is an important material property used when interpreting these data (see Jackson [2015] for an overview). The zeta potential also controls the magnitude and polarity of the seismoelectric response [e.g., Pride, 1994;Schoemaker et al, 2012;Grobbe et al, 2014;Grobbe and Slob, 2016]. Rock wettability is strongly controlled by the zeta potential [e.g., Buckley et al, 1989;Strand et al, 2006;Hiorth et al, 2010;Jackson et al, 2012] and subsurface engineering processes, such as modifying the composition of injection brine during waterflooding of hydrocarbon reservoirs, are affected by its value [e.g., Strand et al, 2006;Zhang et al, 2007;Yousef et al, 2011;Mahani et al, 2016].…”

Seismo‐electromagnetic thin‐bed responses: Natural signal enhancements?

“…This boosted the geophysical research on seismo‐electromagnetic phenomena. Several laboratory experiments [e.g., Jouniaux and Pozzi , ; Zhu and Toksöz , ; Schakel et al , ], numerical modeling experiments [e.g., Haartsen and Pride , ; Haines and Pride , ; Garambois and Dietrich , ; Zyserman et al , ; Grobbe and Slob , ; Kröger et al , ; Grobbe et al , ; N. Grobbe et al, Comparison of eigenvectors for coupled seismo‐electromagnetic layered‐Earth modeling, submitted to Geophysical Journal International , 2015], and field tests [e.g., Butler et al , ; Thompson et al , ; Dean et al , ] have been carried out in attempts to understand this complex physical phenomenon better and to develop applications for the geophysical community.…”

“…We will then numerically investigate what effects thin beds can have on the seismo‐electromagnetic signal, thereby focusing especially on the seismo‐electromagnetic conversion. To this end, we use our analytically based, numerical modeling code ESSEMOD (Electromagneto‐seismic and seismo‐electromagnetic Modeling) [ Grobbe and Slob , ; Grobbe et al , , N. Grobbe et al, submitted manuscript, 2015]. We observe that certain thin‐bed geological settings can yield constructive interference of the seismo‐electromagnetic responses, amplifying the signal strength with a factor of 3.…”