Reservoir simulation is the key tool to design a field development plan and to evaluate field production performances. Various software products have been created and Oil&Gas industry has gained a broad experience of their application. Creation of the reservoir fluid PVT model (PVT table for reservoir simulators) is an essential part of any integrated reservoir studies. PVT models are usually generated using mathematical algorithms by means of equations of state (EOS).

Whenever fluid PVT models are created for the reservoir simulation a variety of uncertainties in the input data arises due to deficiencies of laboratory equipment, low accuracy and quality of sampling techniques, especially for gas-condensate fields. This paper presents a unique know-how in quality control of PVT studies and application of advanced modeling methods using the EOS.

After identification of main uncertainty sources, a quality check procedure was developed to assess the consistency of PVT samples and to select the most reliable ones for EOS modeling. This procedure is based on simple criteria and should be used to handle with uncertainties in PVT studies.

A generalized EOS tuning algorithm was designed and hereby presented in a form of step by step flowchart which summarizes authors’ experience in EOS modeling. Additionally a new method to modify a reservoir gas composition for a proper initialization of the reservoir simulation model as well as for removing possible inconsistencies in the input data is proposed.

The workflow suggested by the authors was successfully implemented in several reservoir simulation models of the gas-condensate assets managed by LLC SeverEnergia, in West Siberia.

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