1D Resistivity Inversion Software

AGI EarthImager 1D is a Windows 32-bit platform based computer program that interprets one-dimensional (1D) electrical resistivity sounding data and produces a layered resistivity model that reveals subsurface geology. EarthImager 1D processes vertical electrical sounding (VES) data collected with Schlumberger, Wenner, dipole-dipole, pole-pole and other arrays. The forward modeling calculation is based on a 2D finite element method. Both smooth model inversion and damped least squares inversion methods were implemented in EarthImager 1D.

Features:

• Inversion of 1D sounding data. • Support of Schlumberger array, Wenner array, dipole-dipole array and other

sounding arrays. • Automatic iterative processing. • Forward modeling. • Terrain correction. • Multilingual support.

EarthImager 2D Features:

2D Resistivity Inversion Software

• 2D resistivity and IP inversion software.

• 2D ERT (electrical resistivity tomography)

between two or more boreholes.

• Survey planner with graphical model input, for-

ward modelling and virtual survey with actual

command file.

• Inversion of marine continous resistivity profil-

ing(CRP) data.

• Inversion of resistivity data collected with

underwater electrodes.

• Creation of command files for non-standard

and mixed arrays.

• Inversion of resistivity data collected with non-

standard and mixed arrays.

• Multi-lingual support with English, Spanish and

Chinese captions.

• Time Lapse inversion option for resistivity

monitoring from the surface and between

bore holes.

• Automatic identification and removal of noisy and

erroneous data points.

• High definition report quality plat style print-out.

• Topographic correction and print-out of resistivity

section with topographical features.

• Finite difference and finite element modelling.

• No software limit on number of data or number of

electrodes.

• No limit on array type or electrode location.

• User friendly Windows GUI.

• A priori information input.

• Real time scrolling through all iterations using the

mouse wheel, creates “movie like” animation.

• Seamless operation with AGI resistivity instru-

ments.

• Accepts manual data input and from .dat files.

• Windows true type font and true 24-bit color.

Example of Schlumberger, dipole-dipole and pole-dipole joint inversion using EarthImager 2D.

Survey: Electrical resistivity data, recorded in

Kenya 2006 for ground water exploration.

Instrument: SuperSting R8/IP with 84 electrodes at

20 meter spacing.

Electrode array: Combination of dipole-dipole,

Schlumberger and pole-dipole.

Processing: Joint inversion using the EarthImager

2D inversion software.

2D Resistivity Inversion

Reads Sting data (and other instrument data formats) and

produces a default setting inversion, valid in most cases,

after only a few clicks. For advanced processing there are

a number of settings for full user control of the inversion

process. Report ready high definition graphic output in the

form of engineering plate style drawing with title block.

2D Electrical Resisistivity Tomography (ERT)

The software automatically detects bore hole data set for

immediate ERT processing. There is an editor for “bad”

electrode and “bad” data removal. From iteration to itera-

tion the data misfit is displayed in a scatter plot. There is

also a data cross plot (raw versus inverted apparent resis-

tivity data) available as well as a diagram showing the

convergence curve.

Survey Planner

The survey planner is used for feasability studies of resis-

tivity imaging projects. First load a command file, then

enter the expected geological features with their expected

resistivities in a graphical input interface. Then run the

simulation using the actual command file and the soft-

ware will perform a virtual survey over the synthetic

model. The result of the virtual survey is then inverted

and the inversion result can be compared to the original

model within seconds.

Topography Correction

In case of terrain relief it may be neccessary to include

topography correction in the inversion process. Data

with terrain elevation is read from a “terrain file“ and the

software will automatically perform an inversion using a

finite element model.

Advanced Geosciences, Inc.12700 Volente Rd., Austin Texas 78726, USA

Tel +1 512-335-3338 Fax +1 512-258-9958E-mail: sales@agiusa.com

Web site: http://www.agiusa.com

Time Lapse Monitoring

The optional Time Lapse function is used for any monitor-

ing situation. It could, for example, be used to detect leak-

age at a landfill site. In such a case, the resistivity image

is first recorded as "background" (before any leakage).

After the initial "background" survey, the survey is repeat-

ed at regular intervals in the same way (electrodes in the

same place using the same array type, etc.) so that any

change in the ground can be detected. The time lapse

function uses the inverted background section when

inverting the "new" section and the result is presented as

the difference between the two sections.

3D Resistivity Inversion Software

• 3D resistivity forward modeling and inver-

sion.

• Surface resistivity imaging and cross bore-

hole resistivity tomography.

• Automatic noisy data rejection.

• 3D data visualization and user interaction

such as pan, zoom and rotation.

• Volume rendering with user-friendly trans-

parency control.

• Dynamic slices for interactive interpretation

• Multiple static slices of 3D volume.

• Unique data scatter plot showing electrode

locations and data distribution.

• Crossplot showing convergence of inversion

process.

• 3D survey planner for numerical simulation.

• Bad electrode recognition and removal.

• Saving images in one of bitmap, JPEG, PNG,

TIFF, PostScript formats.

• Utility for extraction of 2D data sets from a 3D

data set for 2D inversion.

• Seamless operation with AGI resistivity instru-

ments.

• No software limit on number of data or num-

ber of electrodes.

• No limit on array type or electrode location.

• Sandbox module for resistivity imaging in a

confined space.

• 4D time lapse inversion module.

• Long electrode module to handle line sources.

Features:

3D

Advanced Geosciences, Inc.12700 Volente Rd., Austin Texas 78726, USA

Tel +1 512-335-3338 Fax +1 512-258-9958E-mail: sales@agiusa.com

Web site: http://www.agiusa.com

Electrode location and apparent resistivity

scatter plot

Initially apparent resistivity is displayed in a scatter plot.

The electrode location is displayed to the left. The elec-

trode “structure” can be grabbed by the mouse and

moved so that electrodes which are hidden behind clos-

er electrodes can be seen.

Apparent resistivity crossplot

When the inversion process is started, the resistivity vol-

ume is displayed to the right and an apparent resistivity

crossplot is displayed to the left. The crossplot shows the

calculated apparent resistivity versus the measured appar-

ent resistivity. As the inversion procedure progresses, the

data points will move towards a 45 degree line, indicating

that the calculated apparent resistivities approaches the

value of the measured apparent resistivities, i.e. showing

the convergence of the inversion process.

Slices of 3D inverted resistivity image

The inverted resistivity volume can be

“sliced” in any direction and viewed from

any angle.

Color palette

The user have full control of color and

color levels. A specific color scale can

be saved as an .lvl file and later used for

other survey presentations.

Transparency

Certain colors can be made more or less

transparent, making it possible to “look

into the resistivity volume”.