Work out formation volume factor instantly with clear inputs, formula shown and shareable results.
Standing's correlation gives Bo = 0.9759 + 0.00012 x [Rs x sqrt(gas SG / oil SG) + 1.25 T]^1.2, the ratio of oil volume at reservoir conditions to volume at stock tank conditions. Bo exceeds 1 because dissolved gas and thermal expansion swell the oil underground.
Standing correlation
Bo = 0.9759 + 0.00012 x [Rs x sqrt(gamma_g / gamma_o) + 1.25 T]^1.2
Oil gravity
Oil SG = 141.5 / (131.5 + API)
It converts reservoir volumes to sales volumes. A Bo of 1.3 means every barrel produced at surface occupied 1.3 barrels of pore space, which directly scales reserves and material balance calculations.
Whenever PVT laboratory data exists, use it. Correlations carry 5-15% error and were fitted to particular crude families, so volatile oils and heavy crudes are often poorly represented.