Seismoelectric and Seismomagnetic Measurements in Fractured Borehole

نویسندگان

  • Zhenya Zhu
  • M.Nafi Toksoz
چکیده

Seismoelectric and seismomagnetic fields generated by acoustic waves in fluid-saturated fractured borehole models are experimentally investigated with an electrode and a Halleffect sensor. In a borehole with a horizontal fracture, the Stoneley and flexural waves induce seismoelectric and seismomagnetic fields on the borehole wall and an electromagnetic wave propagating with light speed at the horizontal fracture. In a borehole with a vertical fracture, the acoustic field generated by a monopole or dipole source is similar t.o that in a borehole wit.hout a vertical fracture. However, the acoustic wave propagating along the vertical fracture induces seismoelectric and seismomagnetic fields, whose apparent velocities are equal to that. of a Stoneley wave. Experimental results show that two different kinds of electric and magnetic fields are generated by acoustic waves in borehole models with horizontal and/or vertical fractures. One is an elect.romagnetic wave propagating with light speed. The second is a stationary or localized seismoelectric and seismomagnetic field. Seismoelectric and seismomagnetic measurements might be a new logging technique for exploring fract.ures in a borehole.

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تاریخ انتشار 2012