Tech Talks

#14 Modeling of CO2 Properties

Just 10 years ago, the oil industry primarily saw CO2 as a gas that could potentially be used to enhance the oil recovery through injection into oil reservoirs. CO2 is relatively miscible with heavy hydrocarbons and a miscible drive can develop at moderate reservoir pressures.  Today, much focus on CO2 has shifted to Carbon Capture Storage (CCS). It …

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#13 Density of Brine

Accurate correlations exist for the density of pure water. An example is the model of Keyes et al. [1], which is used in PVTsim Nova. Formation water produced together with gas and oil is not pure, but contains dissolved salts, and these salts can have a significant effect on the density. The importance of water …

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#10: Common EoS Model Development for Reservoir Fluids with Gas injection

One of the most challenging EoS modeling tasks is to develop a common EoS model for multiple fluids with gas injection. With gas injection being used as an EOR technique for shale fluids, reservoir engineers working with PVT modeling of shale fluids are frequently facing such task.  The time spent on developing a common EoS …

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#9: PR-CPA in PVTsim Nova 4

Calsep introduced the Cubic Plus Association (CPA) model in PVTsim Nova 2 in 2015. CPA takes into consideration that the thermodynamic properties of polar and non-polar substances of approximately the same molecular weight may deviate substantially because of association between the polar molecules. Water and methane, for example, have approximately the same molecular weight, but …

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#8: Reservoir Temperature from Well Test Data

Knowledge about the reservoir temperature is important for reservoir modeling and field development, but the temperature measured in exploration wells is seldom representative for the reservoir temperature. In a paper presented at SPE ATCE in Dubai in September 2016, Meisingset (Statoil) and Pedersen (Calsep) outline a procedure for determining the reservoir temperature from well test …

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#7: GERG-2008 for Highly Accurate Natural Gas Properties

Cubic equations of state are the standard in oil industry. They are successful because of their versatility, but users of cubic equations must accept minor deviations from experimental data for most physical properties. For some applications such deviations are unacceptable, one example being volumetric gas calculations. The commercial value of a given volume of gas …

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#6: Gas Injection as an Enhanced Recovery Technique for Gas Condensate Reservoir Fluids

Gas injection has for decades been used to enhance oil recovery (EOR). The injected gas keeps the reservoir pressure high and blends with the reservoir fluid to possibly develop a miscible zone that will prevent gas from behind in penetrating and creating a gas break through. The lowest pressure at which a miscible zone can …

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