Diagnosis on Physico-Chemical Properties of Oil Blending in Azerbaijan Oil Fields Based on the Additivity Rule

The blending of rheologically complex crude oils with each other or with condensates presents challenges such as sedimentation, phase separation and viscosity changes. Storage, transportation and dehydration processes are also affected due to the non-additive behavior of oil mixtures. This study examines the impact of blending on key physical-chemical properties, including density, viscosity, freezing point and demulsification efficiency. Crude oil samples from the "Bulla-BN" and "Siyazan-SN" fields in Azerbaijan were blended in various ratios and analyzed using GOST standards. Results showed that blending led to anomalous deviations from the additivity rule, particularly when BN oil reached 50%, causing sharp increase in density and viscosity. Additionally, demulsifier consumption varied significantly based on blending ratios, with some mixtures exhibiting a positive synergy effect that reduced reagent usage. For example, at a 60% dehydration level, demulsifier consumption was reduced to 17 g/t for a 30:70 oil-1 to oil-2 blend and 10 g/t for a 40:60 blend. This study provides insights into optimizing crude oil blending for improved transportation, processing efficiency and economic evaluation. The findings contribute to better demulsification strategies and pricing accuracy in blending operations.