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 …
#10: Common EoS Model Development for Reservoir Fluids with Gas injection Read More »
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 …
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 …
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 …
#7: GERG-2008 for Highly Accurate Natural Gas Properties Read More »
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 …
#6: Gas Injection as an Enhanced Recovery Technique for Gas Condensate Reservoir Fluids Read More »
PVT reports often lists separator corrected Gas/Oil Ratios (GORs), Gas and Oil Formation Volume Factors (FVFs), etc. together with measured Differential Liberation (DL) and Constant Volume Depletion (CVD) data. The separator corrected black oil properties listed in PVT reports are calculated using empirical correlations. But, what does separator corrected black oil properties stand for and …
With PVTsim Nova 2.0 Calsep is introducing the CPA equation of state as one of the EoS alternatives. The CPA equation of state was presented by Kontogeorgis et al. (1996). CPA stands for Cubic Plus Association, which refers to a classic cubic equation of state with an association term. More specifically CPA combines the SRK …
Calsep recently got access to data for the compositional variation with depth in five North Sea reservoirs. All five reservoirs have a gas-oil contact in the interval fluid samples were taken. Figure 1 shows the variation in saturation pressure with depth in two of the reservoirs. The depths are relative to the depth of the …
It was a major achievement when Peneloux et al in 1982 presented the method for volume correcting a cubic equation of state. It enabled liquid densities to be matched using a cubic equation, which was not possible with the equations in their original form. Prior to that time cubic equations had mainly been used to …
#2: How good are the predictions of sound velocity with an equation of state? Read More »
Cubic equations have been an industrial standard in oil industry since the nineteen eighties, but in the original form those equations are unable to handle the mutual solubility between hydrocarbons and aqueous components. Formation water is often produced together with petroleum reservoir fluids and hydrate inhibitors may have to be added to prevent hydrate formation …
#1: Huron-Vidal Mixing Rule. A Unique Combination of a Cubic Equation and a GE model Read More »
