A practical approach to derive heterogeneity index using an integrated petrophysical data analysis

Area of Science:

• Geosciences
• Petroleum Engineering
• Reservoir Characterization

Background:

• Reservoir heterogeneity significantly impacts hydrocarbon recovery and production strategies.
• Accurate quantification of heterogeneity is crucial for effective reservoir management and simulation.
• Traditional methods often rely on core data, which can be sparse and expensive.

Purpose of the Study:

• To quantify and evaluate various indicators of reservoir heterogeneity in the Sarvak reservoir.
• To explore the relationship between conventional heterogeneity indices and log-derived parameters.
• To introduce novel, log-based indicators for reservoir heterogeneity assessment.

Main Methods:

• Analysis of petrophysical logs, including Fullbore Formation Micro Imager (FMI) logs.
• Calculation of heterogeneity indicators such as skewness of porosity and permeability, variography, and sorting index.
• Correlation of these indices with parameters like residual oil (S_or) and reservoir quality index (RQI).

Main Results:

• Skewness of porosity and permeability are significant indicators of heterogeneity.
• Variography range correlates positively with the coefficient of variation (CV) of porosity.
• The FMI-derived sorting index shows a high correlation with the CV of porosity.
• Velocity deviation log (VDL) and residual oil (S_or) exhibit an inverse relationship with the CV of porosity.

Conclusions:

• Novel indices, including skewness and the FMI sorting index, effectively characterize reservoir heterogeneity.
• Petrophysical logs can be utilized to assess reservoir heterogeneity in the absence of core data.
• The findings provide valuable tools for reservoir characterization and management using readily available log data.