Seismic-Based Lithology Classification
Lithology Prediction Through Rock Physics Transformation of Seismic Inversion Attributes
Lithology classification defines the elastic signature of lithology and fluid types using rock physics analysis and well data through the Bayesian estimation theory. The signatures are applied to seismic inversion attributes to generate 3D maps of reservoir properties (e.g., porosity and saturation) with associated probabilities and uncertainties.
The aim of the lithology classification is to build a 3D volume of reservoir properties that can highlight and quantify the pay as hydrocarbon pore volume versus the nonproductive sections. Typical reservoir properties considered for lithology prediction are volume of sand, porosity, and fluid saturations.
Lithology and fluid class discrimination
Lithology classification involves analysis of the well data for lithology and fluid class groups.
Well data upscaling
Input well data is prepared through the well data conditioning functionality, and relationships are established between elastic measurements and physical rock properties using rock physics modeling. Petrophysical logs are used to define lithology, porosity, and fluid classes, each with associated compressional velocity, shear velocity,and density attributes.
Distribution analysis
The rock property class units are projected into 3D space as defined by seismic attributes, such as compressional impedance, shear impedance, and density. Nonparametric probability functions (PPFs) are derived from the cluster analysis as a representation of the variability in the formation properties given by the wells. The most likely attribute is calculated given the seismic attribute or combination of attributes based on the maximum posteriori rule.
Lithology prediction
PPFs are applied to the elastic attribute cubes from the seismic inversion to produce a lithology prediction volume and its associated uncertainty. The interactive environment for analysis and quality control (QC) of the lithology classification enables rapid visualization and data interrogation throughout the workflow.
Related resources
Request More Information