Using borehole electroseismic measurements to detect and characterize fractured (permeable) zones

Abstract

We present a new type of field measurement capable of detecting and characterizing fractured (permeable) zones intersecting a borehole. The method is based on measuring electrical fields generated by a borehole Stoneley wave. In this paper, we describe the measurement technique, present field data, and propose a theoretical model, which correctly predicts amplitudes and phases of the electrical fields measured in the borehole experiment.The theoretical model and the field data demonstrate that the measurements of the Stoneley-wave-induced electrical fields can yield information about the interconnected porosity, and possibly about the permeability of the formation around the borehole. We derive an estimate of the interconnected porosity from the field data, and show that it correlates well with the density of fractures intersecting the borehole. Our results suggest that the borehole electroseismic method can be developed into a logging or a VSP tool, with possible applications in reservoir characterization.

EM Monitoring of Crustal Processes Including the Use of the Network-MT Observations

“…The first concerns electromagnetic variations due to the vibration of the seismic wave (Russel et al 1997). This is mainly studied as a potential tool in geophysical exploration (Butler et al 1996;Mikhailov et al 1997Mikhailov et al , 2000Beamish 1999;Garambois and Dietrich 2001). Based on the macroscopic equations of Pride (1994), Haartsen and Pride (1997) and Garambois and Dietrich (2002) developed full waveform numerical simulation codes of seismo-electromagnetic wave conversions in fluid-saturated stratified porous media.…”

Finite element modeling of SHTE and PSVTM electroseismics

“…There is empiric evidence demonstrating that seismic waves propagating through near-surface layers of the Earth induce electromagnetic disturbances that can be measured at the surface (seismoelectric effect) (Pride and Haartsen, 1996;Mikhailov et al, 1997Mikhailov et al, , 2000; and also recent tests suggest that the reciprocal process, i.e. surface measurable acoustic disturbances induced by electromagnetic fields (electroseismic effect), is also possible (Thompson, 2005;Thompson et al, 2005;Hornbostel and Thompson, 2007).…”

Research and experimental testing of a new kind electrokinetic logging tool

“…From the frequency spectrum analysis, we see that the dominant frequency gradually drifted to low frequencies and the bandwidth (3 dB bandwidth) gradually narrowed. Therefore, the lowfrequency component of the acoustic waves transmitted by the electrokinetic detectors could improve, which would stimulate Stoneley waves that generate the downhole electrokinetic effect (Mikhailov et al, 2000). The efficiency of the downhole acoustoelectric conversion could also improve.…”

“…Thompson and Gist (1993), Butler et al (1996), Mikhailov et al (1997) conducted seismoelectric effect field observation. More recent studies include laboratory experiments (e.g., Zhu et al, 1994;Wang et al, 2010); theoretical and experimental investigations of the seismoelectric effect mechanism (e.g., Shi, 2001;Yan et al, 1999); seismoelectric conversion experiments in model boreholes (e.g., Hunt and Worthington, 2000;Mikhailov, 1998;Mikhailov et al, 2000;Zhu et al, 1999;Zhu and Toksoz, 2005;Chen et al, 2003); and numerical modeling of the acoustoelectric effect (e.g., Hu et al, 2001;Hu et al, 2003;Hu and Wang, 2000). Electrokinetic logging is a new logging method, also known as seismoelectric well logging and acoustoelectric effect logging.…”