2.5D Constrained inversion
An advanced inversion routine which allows the user to prejudice an inversion result towards a structure derived from additional data – often seismic data.
This can often result in capturing the vertical resolution of seismic data and transferring it to the CSEM result.
This frequently results in sharper images of resistive bodies and may lead to an increase in accuracy of depth to the resistor.
This technique is also ideal for testing a number of alternative target scenarios resulting from conflicting interpretations of geophysical data in the area. Particular scenarios may either be discounted, or relative probabilities between competing scenarios identified.
The constrained inversion routine prejudices an inversion towards operator input parameters. Constraint can take three forms: prejudicing the background resistivity towards a user defined model, prejudicing the target resistivity, thickness and /or depth, or where a priori information indicates there is a sharp change in the geo-electric structure, enabling the inversion to model a sharp boundary.
Note that it does not force the data to fit these parameters if the data does not support the prejudiced model. A number of quality control parameters are available to the user to monitor the progress of the inversion, and to assess the degree to which the prejudicing is improving the result.
As there is a degree of interpretive decision making involved in this process, constrained inversion is often run in close co-operation with geoscientists from our clients.