A feasible research of rock porosity and water saturation impact on audio-magnetotelluric propagation in porous media

Abstract:

Abstract: Although various factors have impact on the resistivity of subsurface rock formation, in depth range of general electrical prospecting, the conductive actions of rocks are basically realized relying on the aqueous solutions filled in the pores. Therefore, quantitatively studying the impact of the water level on rock resistivity is important to analyze and classify strata, investigate the underground structures. In this research, we proposed a feasible research on building electric property rock formation models with different porosity and water saturation based on theories of two-phase media. The propagation of audio-magnetotelluric (AMT) waves is simulated by using finite-difference (FD) scheme, and theoretic resistivity distribution is calculated on account of the response of AMT. According to a sequence of synthetic examples, through comparing and analyzing the simulated results with various porosity and water saturation respectively, we discuss the impact on layers resistivity while porosity and water saturation of rock stratum are changing. The results shows the extent that the mentioned factors can have impact on the propagation of AMT waves.

Key words: audio-magnetotelluric modeling, two-phase media, porosity, water saturation, finite-difference