в†‘ Velarde, J., Blasingame, T.A., and McCain Jr., W.D.A Review of Bubblepoint Pressure and Oil Formation Volume Factor Correlations. Generalized Pressure-Volume-Temperature Correlations. API Drilling and Production Practice (1947): 275-287. A Pressure-Volume-Temperature Correlation for Mixtures of California Oils and Gases. Richardson, Texas: Society of Petroleum Engineers of AIME Volumetric and Phase Behavior of Oil Field Hydrocarbon Systems, ninth edition. Hydrocarbon/water surface tension, m/t 2, dynes/cmДead oil surface tension, m/t 2, dynes/cm Gas specific gravity of hydrocarbon components in a gas mixture, air=1 Gas specific gravity adjusted for separator conditions, air=1 Mixture pseudocritical temperature, T, В°R Mean average boiling point temperature, T, В°R Pressure ratio (fraction of bubblepoint pressure) Oil-gas mixture molecular weight, m, lbm/lbm molД«ubblepoint pressure of oil with N 2 present in surface gas, m/Lt 2, psiaД«ubblepoint pressure of oil without nonhydrocarbons, m/Lt 2, psia Gas/oil mixture molecular weight, m, lbm/lbm mol Oil isothermal compressibility at bubblepoint, Lt 2/m, psi -1 Oil isothermal compressibility, Lt 2/m, psi -1 Oil formation volume at bubblepoint pressure, bbl/STB Calculate the pseudocritical temperature of the dead oil.Д¬alculate the pseudocritical temperature of the gas.Д¬alculate the pseudocritical temperature of the live gas/oil mixture.Д¬onvert oil density units from lbm/ft 3 to g/cm 3.Д¬alculate the surface tension between the oil and water phases. Calculate the dead oil surface tension.Дetermine the live oil adjustment factor.Д¬onvert Rs to SI units (dividing 769 Scf/STB by 5.614, the result is 136.98 m 3/m 3)Д¬alculate the live gas/oil surface tension.ДЇor comparison, Baker and Swerdloff = 4.73 dynes/cm.Д®stimate the water/oil surface tension using Firoozabadi and Ramey. Therefore, care should be exercised in the selection of accurate correlations for individual properties.Д®stimate the gas/oil surface tension using the method developed by Abdul-Majeed. correlations, the results are 0.52 cp and 0.503 respectively which are much closer to the measured value. For instance, if the measured bubblepoint viscosity is used in Vazquez-Beggs and AbdulMajeed et.al. Errors in individual correlations can compound and propagate through to the resulting answer. This example illustrates the steps necessary to calculate oil viscosity requiring correlations for dead oil viscosity, bubblepoint viscosity, undersaturated viscosity, and bubblepoint pressure/solution GOR. The measured viscosity at bubblepoint is 0.401 cp.Д¬alculate the undersaturated oil viscosity by applying the Vazquez and Beggs correlation.ДЇor comparison, Beal = 0.730 cp and Kouzel = 0.778 cp. ДЇor comparison, Beggs and Robinson = 0.515 cp. The measured dead oil viscosity is 1.67 cp.Д¬alculate the bubblepoint oil viscosity using the method developed by Chew and Connally. ДЇor comparison, Fitzgerald = 1.808 cp, and Bergman = 2.851 cp. The calculated value is 1.367 bbl/STB with the actual bubblepoint value of 1.398 bbl/STB therefore, the accuracy of the bubblepoint FVF is primarily affected by the accuracy of the undersaturated FVF.Д¬alculate the dead oil viscosity using the correlation from GlasГё. Because this calculation uses the results from multiple correlations, individual correlation error compounds and propagates through to the final result. Which compares to a measured value of 1.367 bbl/STB. With the results from LasaterвЂ™s method for bubblepoint pressure, use Al-ShammasiвЂ™s method for bubblepoint oil FVF, and FarshadвЂ™s equation for isothermal compressibility, the undersaturated oil FVF is given by Undersaturated oil formation volume factor The measured isothermal compressibility is 11.06 Г— 10 -6psi -1.

The measured bubblepoint oil FVF is 1.398 bbl/STB.Д¬alculate the isothermal compressibility of oil using the Farshad correlation. The measured bubblepoint pressure was reported to be 2,479 psia.Д¬alculate the bubblepoint oil formation volume factor (FVF) using the correlation from Al-Shammasi. Therefore, the bubblepoint pressure should be increased by 9.8% to 2,251 psia. Modify the calculated bubblepoint pressure to account for the effects of nitrogen in the surface gas with JacobsonвЂ™s equation. With LasaterвЂ™s relationship between bubblepoint pressure factor and bubblepoint pressure,ДЇor comparison, Standing = 2,316 psia, GlasГё = 2,725 psia, Al-Shammasi = 2,421 psia, and Velardi = 2,411 psia. Calculate the gas mole fraction in the oil,ДЄnd the Lasater bubblepoint pressure factor, Use the Lasater correlation to estimate bubblepoint pressure. 5 Undersaturated oil formation volume factorДetermine the crude oil specific gravity,.3 Bubblepoint oil formation volume factor.

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