DCIP2D manual:  
Program library DCIP2D

Background

DCIP2D is a program library for carrying out forward modelling and inversion of DC resistivity and induced polarization data in two dimensions. The research was funded principally by the mineral industry consortium "Joint and Cooperative Inversion of Geophysical and Geological Data" (1991 - 1997) which was sponsored by NSERC (Canada's National Science and Engineering Research Council) and the following 11 companies: BHP Minerals, CRA Exploration, Cominco Exploration, Falconbridge, Hudson Bay Exploration and Development, INCO Exploration & Technical Services, Kennecott Exploration Company, Newmont Gold Company, Noranda Exploration, Placer Dome, and WMC.

The theoretical framework for DCIP2D is provided in the paper:
Oldenburg, D.W, and Li, Y., 1994, Inversion of Induced Polarization Data, Geophysics, vol 59 p 1327-1341.

Other relevant references include:

• Oldenburg D.W., and Li Y.  (1999), Estimating Depth of Investigation in DC resistivity and IP Surveys, Geophysics, 64 , No.2, 403-416. 
• Yuval,, and Oldenburg , D.W. (1996), DC resistivity and IP methods in acid mine drainage problems: results from the Copper Cliff mine tailings impoundments, Journal of Applied Geophysics, 334 , 187-198.
• Oldenburg D.W., Li Y., and Ellis R.G. (1997), Inversion of geophysical data over a copper gold porphyry deposit: a case history for Mt. Milligan, Geophysics, 62 , No.5, 1419-1431.
• See also the publications page at the UBCGIF website.

DCIP2D capabilities and limitations

Array types

All linear survey surface-array types, including non-standard or un-even arrays, can be inverted. The only limitation is that the mesh must be designed so that electrodes are on mesh nodes. This must be remembered if horizontal distances are not regular, such as when line positions were not corrected for topography.

The GUI was designed with our sponsoring companies in mind, and they are mining exploration firms. Therefore it works well with dipole-dipole, pole-dipole, pole-pole and Wenner or RealSection arrays. Schlumberger, gradient, and other arrays can all be inverted but unfortunately the user interface does not yet handle those types of arrays. As of Dec 05, the RealSection and Wenner array data can be handled by the GUI - see the GUI instructions for details.

The Earth model

Inversion for a 2D model of the earth implies that data were gathered along a survey line at the surface. DCIP2D considers the subsurface in terms of a mesh of rectangular cells. In terms of size, there are usually two cells between electrode positions, and cells are half as thick as their width. There must be several cells of increasing size on all three sides outside the region where current has been injected.

Program library contents

• Executable programs for performing forward modelling and inversion of 2D DC resistivity or induced polarization surveys. Either the WindowsXX or the Linux platforms are supported.
  • DCIPF2D.EXE: program to calculate DC resistivity and/or IP data based on a given model of the earth.
  • DCINV2D.EXE: program to invert 2D DC resistivity data
  • IPINV2D.EXE: program to invert 2D IP resistivity data
• A graphical user interface is supplied for the WindowsXX platforms only. Facilities include
• DCIP2D-GUI.EXE: a primary interface for setting up the inversion and monitoring progress,
• DCIP2D-DATA-VIEWER.EXE: a utility for viewing raw data, error distributions, and for comparing observed to predicted data directly or as difference maps,
• DCIP2D-MODEL-VIEWER.EXE: a utility for displaying resulting 2D models, and graphs of convergence behaviour.
• DCIP2D-MODEL-MAKER.EXE: aA separate utility for building synthetic 2D models and then running forward modelling to produce a synthetic data set.
• Documentation: see Software documentation via the main menu (left panel).
• Example data sets and excercises are provided on the IAG CD-ROM.

Licensing

A constrained educational version of the program is avaliable with the IAG CD-ROM. The educational version is fully functional so that users can learn how to carry out effective and efficient 2D inversions of DC resistivity and IP data. However, RESEARCH OR COMMERCIAL USE IS NOT POSSIBLE because the educational version will NOT work with more than 100 data points or 1,000 cells in the 2D mesh.

Licensing for an unconstrained academic version is available - see the licensing policy document (on the UBC-GIF website).
NOTE: all academic licenses will be time-limited to one year. You can re-apply after that time. This ensures that everyone is using the most recent versions of codes.

Licensing for commercial use is managed by distributors, not by the UBC-GIF research group. Details are in the licensing policy document.

For learning and documentation:

For links to documentation, related utilities, and examples, see the menu to the left.