Interpex IX1D V350: A Comprehensive Guide to 1-D Geophysical Data Inversion Software
Interpex IX1D V350: A Powerful Tool for Geophysical Data Inversion
If you are looking for a reliable and efficient software for processing, interpreting and displaying geophysical data, you might want to check out Interpex IX1D V350. This is a 1-D inversion program that can handle various types of geophysical data, such as DC resistivity, induced polarization, magnetotelluric, frequency-domain electromagnetic, EM conductivity and transient EM. In this article, we will introduce you to the features and functions of Interpex IX1D V350, show you how to use it, and give you some examples of its applications in different fields.
Interpex IX1D V350
What is Interpex IX1D V350?
Interpex IX1D V350 is a software program developed by Interpex Limited, a company that specializes in PC based geophysical software. It is a 1-D inversion program that can invert geophysical data from various sources and methods, and produce models of the subsurface structure and properties. It can also display and export the data and models in various formats.
A brief introduction to the program and its features
Interpex IX1D V350 is based on the principle of inverse modeling, which is a technique that uses measured data to estimate unknown parameters of a model. In geophysics, inverse modeling can be used to infer the electrical resistivity, magnetic permeability, dielectric permittivity, chargeability, conductivity and other properties of the earth's layers from measurements taken at the surface or in boreholes. These properties can provide valuable information about the geology, hydrology, mineralogy and environmental conditions of the subsurface.
Interpex IX1D V350 has several features that make it a powerful tool for geophysical data inversion. Some of these features are:
It supports most DC resistivity arrays, including Wenner, Schlumberger, dipole-dipole, pole-dipole and pole-pole arrays.
It supports resistivity only or resistivity with IP measurements in terms of PFE (percent frequency effect), chargeability in msec or phase in mrad.
It supports magnetotelluric (MT) sounding inversion with apparent resistivity and impedance phase.
It supports horizontal coplanar, vertical coplanar and vertical coaxial frequency-domain electromagnetic in-phase and quadrature measurements made versus frequency or frequency. It also supports EM conductivity data from the Geonics EM31, EM34 and EM38 instruments.
It supports transient EM (TEM) data from various systems, such as Geonics PROTEM, Zonge GDP, Geometrics Stratagem and UTEM.
It allows the user to create layered earth models with up to 100 layers, each with a constant or variable resistivity and thickness. It also allows the user to specify a half-space or a basement layer with a fixed resistivity.
It uses a robust and fast inversion algorithm based on the Occam's inversion method (Constable et al., 1987), which minimizes the model roughness while fitting the data within a specified error level.
It provides various options for the inversion, such as fixing or freeing certain model parameters, setting upper and lower bounds for the resistivity and thickness values, choosing different model norms and weighting schemes, and selecting different inversion modes (smooth or blocky).
It has a user-friendly graphical interface that allows the user to import, edit, display and export the data and models. It also has a batch mode that allows the user to run multiple inversions with different settings.
Interpex IX1D V350 is compatible with Windows operating systems and can be downloaded from the Interpex website . It comes with a comprehensive user manual that explains the program features and functions in detail.
The types of geophysical data that it supports and how it imports them
Interpex IX1D V350 can invert geophysical data from various sources and methods, as long as they can be represented by a 1-D layered earth model. The types of geophysical data that it supports are:
DC resistivity data: These are measurements of the electrical potential difference between two electrodes on the surface or in boreholes, induced by a direct current injected through another pair of electrodes. The potential difference is proportional to the electrical resistivity of the subsurface, which depends on factors such as porosity, fluid content, salinity and mineralization. DC resistivity data can be acquired using different array configurations, such as Wenner, Schlumberger, dipole-dipole, pole-dipole and pole-pole arrays. Interpex IX1D V350 can import DC resistivity data from ASCII files or from files generated by other programs, such as RESIX IP2WIN or RES2DINV .
Induced polarization (IP) data: These are measurements of the electrical potential difference between two electrodes on the surface or in boreholes, induced by an alternating current injected through another pair of electrodes. The potential difference is affected by the electrical resistivity of the subsurface as well as by its chargeability, which is a measure of how much electric charge is stored and released by certain minerals or fluids in response to the applied current. IP data can be expressed in terms of PFE (percent frequency effect), chargeability in msec or phase in mrad. IP data can be acquired using the same array configurations as DC resistivity data. Interpex IX1D V350 can import IP data from ASCII files or from files generated by other programs, such as RESIX IP2WIN or RES2DINV .
Magnetotelluric (MT) sounding data: These are measurements of the natural variations of the electric and magnetic fields on the surface or in boreholes, caused by electromagnetic waves generated by sources such as lightning strikes or solar wind. The electric and magnetic fields are related by Maxwell's equations, which depend on the electrical resistivity of the subsurface. MT sounding data can be expressed in terms of apparent resistivity and impedance phase. Interpex IX1D V350 can import MT sounding data from ASCII files or from files generated by other programs, such as WinGLink or EDIX .
Frequency-domain electromagnetic (FDEM) data: These are measurements of the electric and magnetic fields on the surface or in boreholes, induced by an alternating current transmitted through a coil or a wire loop. The electric and magnetic fields are related by Maxwell's equations, which depend on the electrical conductivity of the subsurface. FDEM data can be acquired using different coil orientations, such as horizontal coplanar, vertical coplanar and vertical coaxial. FDEM data can be expressed in terms of in-phase and quadrature components measured at different frequencies. Interpex IX1D V350 can import FDEM data from ASCII files or from files generated by other programs, such as EMIGMA or EMIX .
EM conductivity data: These are measurements of the apparent apparent electrical conductivity of the subsurface, derived from the ratio of the horizontal electric field to the vertical magnetic field measured at the surface. EM conductivity data can be acquired using instruments such as the Geonics EM31, EM34 and EM38, which operate at different frequencies and coil spacings. Interpex IX1D V350 can import EM conductivity data from ASCII files or from files generated by other programs, such as DAT31 or DAT34 .
Transient EM (TEM) data: These are measurements of the transient electric or magnetic fields on the surface or in boreholes, induced by a sudden change in the current transmitted through a coil or a wire loop. The transient fields decay over time according to the electrical resistivity and permeability of the subsurface. TEM data can be acquired using different systems, such as Geonics PROTEM, Zonge GDP, Geometrics Stratagem and UTEM. Interpex IX1D V350 can import TEM data from ASCII files or from files generated by other programs, such as TEMIX or TEMTD .
Interpex IX1D V350 can also import synthetic data generated by forward modeling programs, such as IX1DFM , which can be used to test the inversion algorithm and to compare different models.
The advantages of using Interpex IX1D V350 over other inversion programs
Interpex IX1D V350 is not the only inversion program available for geophysical data, but it has some advantages that make it stand out from the rest. Some of these advantages are:
It is versatile and flexible: It can handle different types of geophysical data, from different sources and methods, with different formats and units. It can also create different types of models, with different parameters and constraints. It can also perform different types of inversions, with different options and settings.
It is accurate and reliable: It uses a robust and fast inversion algorithm that can fit the data within a specified error level while minimizing the model roughness. It also provides various quality indicators for the data and models, such as RMS error, chi-square value, model norm and resolution matrix.
It is user-friendly and intuitive: It has a graphical interface that allows the user to import, edit, display and export the data and models with ease. It also has a batch mode that allows the user to run multiple inversions with different settings. It also has a comprehensive user manual that explains the program features and functions in detail.
It is compatible and interoperable: It can import data from ASCII files or from files generated by other programs. It can also export data and models to ASCII files or to files compatible with other programs. It can also communicate with other programs through command-line arguments or through dynamic link libraries (DLLs).
It is affordable and accessible: It has a reasonable price compared to other inversion programs. It also has a free trial version that allows the user to test the program features and functions for 30 days. It also has a website that provides information, support and updates for the program.
Interpex IX1D V350 is therefore a powerful tool for geophysical data inversion that can help you achieve your goals and objectives in exploration and research.
How to use Interpex IX1D V350?
In this section, we will show you how to use Interpex IX1D V350 to perform inversion on geophysical data. We will use an example of DC resistivity data acquired using a Wenner array configuration. The data file is called WENNER.DAT and it contains 20 measurements of apparent resistivity versus electrode spacing. The file format is as follows:
# This is a comment line # Data file for DC resistivity Wenner array # Columns are: Electrode spacing (m), Apparent resistivity (ohm-m), Standard deviation (ohm-m) 5 10 0.5 10 15 0.75 15 20 1 20 25 1.25 25 30 1.5 30 35 1.75 35 40 2 40 45 2.25 45 50 2.5 50 55 2.75 55 60 3 60 65 3.25 65 70 3.5 70 75 3.75 75 80 4 80 85 4.25 85 90 90 4.5 0.25 95 5 0.25 100 5.5 0.25
The steps to use Interpex IX1D V350 are as follows:
How to create and edit models from the keyboard or spreadsheet
The first step is to create a model for the inversion. A model is a representation of the subsurface structure and properties, consisting of layers with constant or variable resistivity and thickness. Interpex IX1D V350 allows you to create and edit models from the keyboard or from a spreadsheet.
To create a model from the keyboard, you need to enter the number of layers, the resistivity and thickness values for each layer, and the type of model (constant or variable). For example, to create a three-layer model with constant resistivity and thickness, you can enter the following commands:
> NEW Enter number of layers: 3 Enter resistivity for layer 1: 10 Enter thickness for layer 1: 5 Enter resistivity for layer 2: 20 Enter thickness for layer 2: 10 Enter resistivity for layer 3: 30 Enter thickness for layer 3: -1 Enter type of model (C/V): C
The negative value for the thickness of the last layer indicates that it is a half-space or a basement layer with a fixed resistivity. The type of model C indicates that it is a constant model, meaning that the resistivity and thickness values are fixed and not inverted.
To create a model from a spreadsheet, you need to open an Excel file that contains the model parameters in columns. The first column should contain the layer number, the second column should contain the resistivity value, and the third column should contain the thickness value. For example, to create the same three-layer model as above, you can use the following Excel file:
LayerResistivityThickness
1105
22010
330-1
To import the model from the Excel file, you can enter the following commands:
> NEW Enter number of layers: -1 Enter name of Excel file: MODEL.XLS Enter type of model (C/V): C
The negative value for the number of layers indicates that it is read from the Excel file. The name of the Excel file should include the extension .XLS. The type of model C indicates that it is a constant model.
To edit a model, you can use the EDIT command, which allows you to change the resistivity and thickness values for each layer, as well as the type of model. For example, to change the resistivity of layer 2 to 25 ohm-m and make it a variable layer, you can enter the following commands:
> EDIT Enter layer number to edit: 2 Enter new resistivity for layer 2: 25 Enter new thickness for layer 2: * Enter new type for layer 2 (C/V): V
The asterisk (*) indicates that the thickness value is unchanged. The type of model V indicates that it is a variable layer, meaning that the resistivity and thickness values are inverted.
How to fix parameters for the inversion calculations
The second step is to fix some parameters for the inversion calculations. These parameters include the error level, the inversion mode, the model norm, and the weighting scheme. These parameters affect how the inversion algorithm fits the data and minimizes the model roughness.
To fix these parameters, you can use the FIX command, which allows you to enter or change these parameters interactively. For example, to fix these parameters with some typical values, you can enter the following commands:
> FIX Enter error level (percent): 5 Enter inversion mode (S/B): S Enter model norm (L0/L1/L2): L1 Enter weighting scheme (U/E): E
The error level is a percentage value that indicates how much deviation from the data is allowed in the inversion. A higher error level means more tolerance for data misfit, while a lower error level means more accuracy in data fit.
The inversion mode is either S or B, indicating indicating whether the inversion is smooth or blocky. A smooth inversion produces a model with continuous variations of resistivity and thickness, while a blocky inversion produces a model with discrete changes of resistivity and thickness.
The model norm is either L0, L1 or L2, indicating the type of regularization used to minimize the model roughness. The L0 norm minimizes the number of layers, the L1 norm minimizes the sum of absolute values of resistivity and thickness changes, and the L2 norm minimizes the sum of squares of resistivity and thickness changes.
The weighting scheme is either U or E, indicating whether the data are weighted uniformly or according to their estimated errors. A uniform weighting scheme gives equal importance to all data points, while an error-based weighting scheme gives more importance to data points with smaller errors.
How to perform inversion with different options and settings
The third step is to perform inversion on the data using the model and parameters that you have created and fixed. Interpex IX1D V350 allows you to perform inversion with different options and settings, such as single or multiple iterations, smooth or blocky mode, forward or inverse calculation, and analysis of equivalence or resolution.
To perform a single iteration of inversion, you can use the CALCULATE/INVERSE/SINGLE ITERATION command or press F9. This will run the inversion algorithm once and update the model and the data display. You can repeat this command until you are satisfied with the fit between the data and the synthetic curve.
To perform multiple iterations of inversion, you can use the CALCULATE/INVERSE/MULTIPLE ITERATIONS command or press F10. This will run the inversion algorithm until it converges to a stable solution or reaches a maximum number of iterations. You can specify the maximum number of iterations and the convergence criterion in the OPTIONS/INVERSION SETTINGS dialog box.
To switch between smooth and blocky mode, you can use the OPTIONS/INVERSION MODE command or press F11. This will change the inversion mode from S to B or vice versa. You can also change the inversion mode for each layer individually by using the EDIT command.
To perform a forward calculation, you can use the CALCULATE/FORWARD command or press F8. This will calculate the synthetic curve for the current model without changing it. You can use this command to test different models and compare them with the data.
To analyze equivalence, you can use the CALCULATE/ANALYZE EQUIVALENCE command or press F12. This will generate a range of models that fit the data within a specified error level. You can specify the error level and the number of models in the OPTIONS/EQUIVALENCE SETTINGS dialog box. You can also display and export the equivalent models using the VIEW/EQUIVALENT MODELS command.
To analyze resolution, you can use the CALCULATE/ANALYZE RESOLUTION command or press F7. This will calculate and display the resolution matrix for the current model, which shows how well each layer parameter is resolved by the data. You can also display and export the resolution matrix using the VIEW/RESOLUTION MATRIX command.
How to display and export the inversion results and models
The fourth step is to display and export the inversion results and models. Interpex IX1D V350 allows you to display and export the data and models in various formats, such as graphs, tables, maps and profiles.
To display the data and models graphically, you can use the VIEW/GRAPH command or press F5. This will open a graph window that shows the data points, the synthetic curve, the model layers, and the error bars. You can customize the graph appearance by using the OPTIONS/GRAPH SETTINGS dialog box. You can also zoom, pan, print and copy the graph by using the toolbar buttons or the right-click menu.
To display the data and models in tabular form, you can use the VIEW/TABLE command or press F6. This will open a table window that shows the data values, the model parameters, and the quality indicators. You can customize the table appearance by using the OPTIONS/TABLE SETTINGS dialog box. You can also sort, filter, print and copy the table by using the toolbar buttons or the right-click menu.
To display the data and models in map form, you can use the VIEW/MAP command or press F4. This will open a map window that shows the location of each data point on a map background. You can customize the map appearance by using the OPTIONS/MAP SETTINGS dialog box. You can also zoom, pan, print and copy the map by using the toolbar buttons or the right-click menu.
To display the data and models in profile form, you can use the VIEW/PROFILE command or press F3.