Patent ID: 8762062
Filing Date: 2014-06-24
Classification: G01V

Abstract:
1. A method for estimating at least one geophysical property, the method comprising: using a plurality of transmitter electrodes distributed in a conductive medium, periodically passing rectangular current impulses through the media; collecting a sequence of sounding data between each of the impulses with a receiver electrode disposed between the plurality; determining a first difference and a second difference of the electric potential between points of the collected data; when each of the transmitters is excited, acquiring a focused measurement by simultaneously calculating a combination of at least one orthogonally weighted measurement and at least one axially weighted measurement obtained by the receiver, wherein the weighting is obtained from a condition of equipotentiality in four outer electrodes of the receiver; using the focused measurement to estimate at least one of the following geophysical properties of the geological formation: σ(iωσ σ η—a coefficient of induced polarization, and τ—a time decay constant of the induced polarization; according to the relationship where ∇× represents operator curl (or rotor); E (iω) represents the electric field of a dipole source, expressed in the equation in frequency domain, μ represents magnetic permeability,