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Crude management is a useful and necessary tool for successfully incorporating unconventional oil into the refinery crude slate. For example, opportunity crudes can lead to a wide range of processing problems: high TAN crudes may lead to extensive corrosion; highly asphaltic crudes may cause thick rag layers in the desalter or fouling issues downstream; highly contaminated crudes may cause catalyst deactivation, etc. Important components of crude management are analysis and miscibility determination, assays and simulation, selection and blending, blending mechanics, oil storage, and logistics.
Crude compatibility is a very important property to consider when making decisions regarding which crude to purchase. Blending crudes that are incompatible can lead to extensive fouling and processing difficulties due to unstable asphaltenes. These problems can quickly reduce the benefits of purchasing the opportunity crude in the first place. For example, extensive fouling in the crude preheat train may occur resulting in decreased energy efficiency, increased CO2 emissions, and increased frequency at which heat exchangers need to be cleaned. In a worst-case scenario, crude throughput may be reduced leading to significant financial losses.
In order to make prudent decisions regarding crude purchases, it is important to have access to up-to-date, accurate crude assays. Using old assays may result in an inaccurate picture of the value of the crude; crude quality is continually changing as the wells mature and as crude from different wells are blended. For example, the API of Forties drifted from an average of about 40° in 1996 to about 44.5° in 2006. Therefore, recent crude assays must be used in order to obtain the most accurate picture of the value of the crude. Sometimes, even the variation between different cargoes within a short time span can be significant. For example, assays of Forties Blend have revealed that API variations of up to 3° can occur just from one cargo to another.