Oil Compressibility Calculator
Calculate undersaturated oil compressibility (co) using the Vasquez-Beggs correlation.
Input Parameters
co = (-1433 + 5×Rs + 17.2×T - 1180×γgs + 12.61×API) / (10&sup5; × P)
Oil Compressibility
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psi-1
co (×10-6)
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psi-1
co (bar-1)
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How this was calculated
Vasquez-Beggs (1980): Empirical correlation for undersaturated oil compressibility above bubble point pressure.
Range: API 15-60, GOR 20-2000 scf/STB, T 100-340°F, P 500-5000 psia. Gas gravity assumed 0.75 if not specified.
Note: This correlation applies above the bubble point. Below Pb, total system compressibility includes free gas effects.
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Oil compressibility (co) measures how much oil volume changes per unit pressure change. For undersaturated reservoirs (above bubble point), co is the dominant term in the total system compressibility, which directly affects material balance calculations, well test interpretation, and production forecasting.
Typical values range from 5-25 x 10^-6 psi^-1 for light oils and 3-10 x 10^-6 for heavy oils. Built by Groundwork Analytics.