DOI: 10.5281/zenodo.17350656
title: Numerical investigation of different petrophysical joint inversion schemes

description: Dataset Description

This dataset supports the numerical study of petrophysical joint inversion (PJI) frameworks on subsurface electrical properties modelled with temperature and surface conduction effects. It contains the scripts and resources necessary to reproduce all synthetic model scenarios, inversion experiments, and visualizations presented in the manuscript.

The dataset is organized into three main components:

Directory: 01_synthetic_models

This folder includes the model setup and synthetic data generation scripts for three different subsurface scenarios (A–C):





Model A – Purely electrolytic conduction (Archie’s law, temperature-independent).




Model B – Electrolytic and surface conduction (temperature-dependent).




Model C – Electrolytic and surface conduction (temperature-dependent) with variations in the saturation exponents.



Each subdirectory (A, B, C) contains:





01_create_model.py – Defines the hydrogeological model (porosity, water, ice, air content, CEC).




02_create_syn_data.py – Generates synthetic seismic and electrical data for the corresponding model configuration.




Supporting files such as:





mesh.bms, geom.bms – Model geometry and mesh files.




tttrue.dat, veltrue.dat – Seismic travel time data.




ert*true.dat, rho*true.dat – Electrical data and resistivity distributions.




true_model*.npz – Complete model parameter arrays for each scenario.




sensors.npy – Electrode/geophone locations.





2. Joint Inversion Execution

Directory: 02_joint_inversion

This folder contains all inversion scripts and results for the three sets of experiments described in the manuscript:

2.1 Archie-Based Inversions (01_archie)

Implements PJI using Archie’s law:





A: Inversion of synthetic Model A.




B: Inversion of synthetic Model B



Each folder includes:



03_joint_inversion.py – Main inversion script.



meshERT.bms, meshSRT.bms – Electrical and seismic meshes.




Result files (*.npz, *.dat, .png) documenting inversion outcomes and data fits.



2.2 Temperature-Constrained Inversions (02_sfccon)

Implements PJI with and without the Soil Freezing Curve (SFC) constraint:





03a_joint_inversion_wosfc.py – Inversion without SFC constraint.




03b_joint_inversion_wsfc.py – Inversion with SFC constraint.



2.3 Saturation Exponent Study (03_satexp)

Assesses sensitivity to the saturation exponent parameters nnn and n^\hat{n}n^:





Includes inversion scripts (03_joint_inversion_v001.py, 03_joint_inversion_v003.py)and results for multiple exponent configurations (0.25–1.75).



3. Visualization and Post-Processing

The following Python scripts reproduce all figures presented in the manuscript:





04a_plot_hg_models.py – Visualizes the hydrogeological reference model.




04b_plot_synthetic_models.py – Plots true synthetic models (A–C).




04c_plot_results_archie.py – Displays inversion results for Archie-based experiments.




04d_plot_results_sfccon.py – Visualizes SFC-constrained inversion outcomes.




04e_plot_results_satexp.py – Illustrates the effect of varying saturation exponents.



Generated figures:





fig01_hydrogeological_model.pdf




fig02_geophysical_models.pdf




fig03_results_archie.pdf




fig04_results_sfccon.pdf




fig05_results_satexp.pdf



Code Availability

All scripts for running the petrophysical joint inversion, including the core inversion engine and petrophysical models, are available on GitHub:





https://github.com/geophilik/petrojoint




https://github.com/florian-wagner/four-phase-inversion



These repositories provide further documentation and source code for extending or adapting the inversion schemes.

Citation

If you use this dataset or scripts, please cite the associated manuscript and include appropriate attribution to the original software repositories.