Crude oil is an exceptionally diverse natural resource, and no two grades are the same. Refineries depend on crude assays to understand crude oil composition, processing behavior, and expected yields. These assays are essential tools for refining planning, crude purchasing decisions, blend optimization, and financial modeling.
A full crude assay provides an extensive set of measurements that describe the crude’s physical and chemical characteristics. Distillation behavior is determined through True Boiling Point distillation under ASTM D2892 and vacuum distillation under ASTM D5236. Additional analyses identify sulfur content, nitrogen levels, metals such as nickel and vanadium, acid number, carbon residue, asphaltene content, and molecular composition. Each of these factors influences how the crude will perform in atmospheric distillation, catalytic cracking, hydro processing, and other refining units.
Refinery operations rely heavily on assay data to predict how much naphtha, kerosene, diesel, and residual material a crude will yield. These projections influence everything from product slate planning to catalyst choice to hydrogen balance management. High-sulfur or high-acidity crudes may require additional processing steps, while metals can poison catalysts and increase operational costs. Accurate assay data allows refiners to fine-tune their configurations and maximize profitability.
Regulatory frameworks influence crude selection as well. MARPOL Annex VI sulfur limits, EPA regulations under 40 CFR Part 80, and various regional low-carbon fuel standards shape which crudes are most economically viable. Assays provide refiners and traders with the information needed to navigate these requirements and maintain compliance.
Trading organizations also rely on assays to compare different crude grades, calculate refinery-specific netbacks, and evaluate the attractiveness of potential purchases. Subtle differences in crude properties can have significant impacts on value when processed through different refinery configurations. Assays also support blend design by identifying how different crude combinations will behave when mixed, reducing the risk of incompatibilities such as asphaltene precipitation or corrosion.
AmSpec provides comprehensive crude assay services that include TBP and vacuum distillation, metals and sulfur analysis, compatibility and stability studies, and custom yield modeling. Our laboratories deliver detailed, decision-ready data that supports refiners, traders, and integrated energy companies in making informed and profitable operational choices.