Pre-Stack Constrained Stratigraphic Inversion

Tricon uses Vanguard© software for reservoir imaging. This approach is deterministic in that it assumes the “convolutional model” as the relationship between Acoustic Impedance (log property) and constructs a 3D interval velocity volume from seismic imaging velocities and the seismic trace. It also employs a Geostatistical approach from well data to generate a constrained background model used to propagate log values along macroinversion process, and micro surfaces. These comprehensive workflows can account for deterministic inversion of angle range or AVO in the PSTM gathers for both soft and hard rock environments.

Geolog software (log analysis/petrophysics) uses stacks to build a complete lithologic model from either recorded or modeled shear data with a suite of estimates built from other log measurements. These models are used to calibrate P-wave Acoustic Impedance and Elastic Impedance. Deliverables include the seismic, that is, P- Impedance and Shear Impedance Outputs, 3 Attribute volumes (Lambda-Rho, Mu Rho and Poisson’s Ratio) and 2 Crossplots (Lambda-Rho vs. Mu Rho) to determine porosity, and Poisson’s Ratio vs. P–Impedance (properties which are computed from the joint inversion processing to determine the lithology).

Pre-Stack Constrained Stratigraphic Inversion is performed simultaneously for all elastic parameters, maximizing consistency between P impedances, S impedances and density. This inversion is model-based, ensuring higher reliability through constraints based on well information and interpretation results. A unique wavelet for each angle stack handles wavelet variations between offsets, enhancing the final resolution of the inverted elastic impedances and density volumes. Global 3D multi-channel operators ensure lateral consistency, attenuating imprint noise from processing and acquisition. The user can integrate non-seismic information into the inversion process, such as the macro-model, micro-structure, and micro-layer topology. Consistency between P and S impedances is achieved by integrating AVO information into the inversion process via Aki & Richards modeling including density information.

By interactively cross plotting the relationships between the well data and the inverted seismic data, we can isolate Geobodies in order to generate Classified Facies Volumes.The AVO pre-stack inversion workflows are best suited to obtain various rock property attributes that tie directly to well control.

For non-conventional reservoirs it is essential to generate various combinations of a suite of products, such as Brittleness, Young’s x Rho Modulus, Poisson’s Ratio and Lambda-Rho/Mu-Rho, in order to characterize properties such as fracture intensity and orientation.


Please see our Inversion in Shales Powerpoint in the Papers & Presentations section.
Papers & Presentations