Creation of a PVT model for a reservoir under data uncertainty

Background: PVT modeling is a critical step in reserve estimation and reservoir simulation of oil and gas fields. Accurate reproduction of fluid properties under different pressure–temperature conditions increases confidence in calculations and improves production forecasts. The accuracy of a PVT model largely depends on the quality of laboratory fluid data, while inconsistencies or errors in experimental results can reduce the reliability of calculated parameters.

Aim: To evaluate the quality and reliability of laboratory data on reservoir fluids from the Cretaceous horizons and to validate consistent PVT regions for model development.

Materials and methods: The quality and reliability of laboratory studies were evaluated using PVTsim software and methodological guidelines for validating reservoir fluid properties, where fluid composition and properties were analyzed based on equations of state.

Results: Analysis of bottomhole and recombined samples showed clear relationships between reservoir fluid properties. Several PVT regions with distinct characteristics were identified. Comparison of simulation results with laboratory data revealed discrepancies, particularly in the measured density of Albian horizon oil. Reservoir oil parameters were adjusted using the PVT model.

Conclusion: This approach removed unreliable laboratory data, provided a more accurate description of reservoir fluid properties, and updated calculation parameters to refine resource estimates.