OpendTect offers various plugins for quantitative seismic interpretation. Seismic Colored Inversion (by Ark cls) is a fast way to convert seismic data to band-limited acoustic impedance. Full-bandwidth Deterministic and Stochastic inversion is offered in plugins with the same names by Earthworks and Ark cls. Using Neural Networks, it is possible to convert seismic information (e.g. acoustic and/or elastic impedance) to rock properties (e.g. Porosity, Vshale etc). The supervised network is trained along well tracks to find the (non-linear) relationship between seismic and well logs.
Purpose: A fast-track approach to invert seismic data to band-limited (relative) acoustic impedance. Theory: A single convolution inversion operator is derived that optimally inverts the data and honours available well data in a global sense. In this way, the process is intrinsically stable and broadly consistent with known AI behaviour in the area. Construction of the operator is a simple process and implementation can be readily performed within the processing module included in SCI. As an explicit wavelet is not required, other than testing for a residual constant phase rotation as the last step, this removes an inherently weak link that more sophisticated processes rely on. Software: OpendTect + Seismic Colored Inversion
Workflow:
Open the attribute set window, add a new Attribute: Colored Inversion, select input seismic and specify a wavelet name.
Press Analyze and Create ... to open the Colored Inversion application.
Select Input Seismic and Well data, select well logs (right-click on the well) and time windows for seismic and wells. To load, press Load seismic and Reload wells, respectively.
Select Design controls and play with the parameters (increase the smoothing operator, toggle range and try reducing the max. frequency, toggle Auto Calc. and change low-cut and high-cut). Notice how the curves change interactively. Choose parameters that yield a smooth spectrum over the seismic frequency band.
Apply the Colored Inversion attribute to the seismic data in batch: Processing - Create seismic output, or on-the-fly: right-click on the element in the tree (e.g. part of an inline).
Tips:
Use the Chart Controller and Zoom options (View menu) to see all graphs simultaneously.
