2.5D amplitude only inversion
A data inversion scheme which produces interpretable geo-electric cross-sections of the subsurface. No a-priori information is included in this process, increasing confidence in the robustness of the resultant models.
Results from 2.5D inversion add significant value over simple 1D reconnaissance modelling: resistors are correctly positioned both laterally and in depth, allowing complex geological structures to be reliably interpreted.
OHM’s inversion schemes are complex iterative processes which perturb a model of the earth using proprietary solution seeking algorithms, until the predicted geo-electric response of the earth matches the observed CSEM data set.
In order to combat non uniqueness issues, a wide range of parameters, including multiple frequencies, are considered in the inversion.
A number of quality control parameters are outputted to the geophysicists to allow them to monitor the inversion’s convergence and to intervene when the inversion is proceeding in undesirable directions.
The inversion can deal with a three dimensional dataset and earth model. The result is output as a 2 dimensional image taking account of the fact that the source response is 3 dimensional hence this is called a 2.5D inversion
The basic inversion algorithms use an Occam scheme causing them to solve for the simplest structure which explains the data. This results in smooth representations of subsurface detail and can often cause bodies to be smeared and appear to have a lower resistivity than in reality. These attributes can be addressed using more advanced inversion methods.