IP4DI: A software for time-lapse 2D/3D DC-resistivity and induced polarization tomography

We propose a 2D/3D forward modelling and inversion package to invert direct current (DC)-resistivity, time-domain induced polarization (TDIP), and frequency-domain induced polarization (FDIP) data. Each cell used for the discretization of the 2D/3D problems is characterized by a DC-resistivity value and a chargeability or complex conductivity for TDIP/FDIP problems, respectively. The governing elliptic partial differential equations are solved with the finite element method, which can be applied for both real and complex numbers. The inversion can be performed either for a single snapshot of data or for a sequence of snapshots in order to monitor a dynamic process such as a salt tracer test. For the time-lapse inversion, we have developed an active time constrained (ATC) approach that is very efficient in filtering out noise in the data that is not correlated over time. The forward algorithm is benchmarked with simple analytical solutions. The inversion package IP4DI is benchmarked with three tests, two including simple geometries. The last one corresponds to a time-lapse resistivity problem for cross-well tomography during enhanced oil recovery. The algorithms are based on MATLAB® code package and a graphical user interface (GUI).

► We developed a code to invert resistivity, frequency-domain and time domain IP data.
► The code include a new time lapse appraoch called the ATC inversion.
► The forward algorithm is benchmarked against analytical solutions.
► An application is shown for an enhanced oil recovery problem.
► Inverson can be 2D, 3D, 2D plus time, 3D plus time.