4D Simultaneous Inversion | Schlumberger

4D Simultaneous Inversion

Quantitative approach to time-lapse data interpretation

The 4D simultaneous inversion method is unique because it offers more insight compared with conventional 4D inversion workflows.

Added insights

  • Independent wavelet estimations for each partial stack and each conventionally acquired survey. Because the wavelet estimations for the different seismic volumes are independent, any variations in amplitude and phase for the different seismic volumes will be captured by the wavelets.
  • Inversion directly for desired rock properties such as acoustic impedance, shear impedance, Poisson's ratio, Vp/Vs, and density as well as the corresponding changes in the desired rock properties. 4D-optimized simultaneous inversion directly inverts for the changes in rock properties, enabling you to directly implement prior models for the changes in rock properties.
  • Global optimization technique, where all partial stacks of all vintages of surveys and all samples within each partial stack are used at the same time through the inversion algorithm. Because all seismic volumes are simultaneously inverted, the 4D simultaneous inversion algorithm finds the model of the subsurface with rock properties and corresponding changes that optimally matches all partial stacks of all vintages of surveys.
Independent wavelet estimation combined with inversion directly for desired rock properties.
Red and yellow show an increase in acoustic impedance due to decreased pore pressure and increased water saturation (left) and an increase in Poisson's ratio due to increased water saturation (right). The increase in Poisson's ratio is confined to the initially oil-saturated zone.

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