Crude Oil Assay Tests List

Crude oil assay tests and testing methods listing.

Intertek's crude oil assay laboratories provide clients with professional, independent, and impartial crude oil quality data needed to make beneficial commercial trading and refining feedstock decisions.

Crude oil assay tests can vary in detail, depth, and scope, depending upon client requirements.

ASTM D2892 distillation of crude oil:

The ASTM D2892 test method is used for the distillation of stabilized crude to a final cut temperature of up to 400ºC (752ºF) Atmospheric Equivalent Temperature (AET). The crude oil is heated and separated by the distillation column into lighter products such as; gasoline, kerosene, naphtha, etc. The lighter products produced in this process are further refined in various refinery processes. This test method employs a fractionating column having an efficiency of 14 to 18 theoretical plates operated at a reflux ratio of 5:1. This test method details procedures for the production of a liquefied gas, distillate fractions, and resid of standardized quality on which analytical data can be obtained, and the determination of yields of the above fractions by mass and volume. This distillation curve corresponds to a laboratory technique, which is defined at 15/5 (15 theoretical plate column, 5:1 reflux ratio) or true boiling point (TBP).

The ASTM D2892 test method can be applied to any petroleum mixture, except liquefied petroleum gases (LPG), very light naphthas, and fractions having an initial boiling point above 400ºC (752ºF).

ASTM D5236 distillation of heavy hydrocarbon mixtures:

The ASTM D5236 method of distillation employs a vacuum pot still with a low pressure drop entrainment separator operated under total takeoff conditions. The reduced pressure allows volatilization at a lower temperature than under atmospheric conditions, thus allowing temperatures up to 565ºC for most samples. This technique avoids “cracking” the oil (caused by long periods of temperatures above 350ºC). The test method applies to the heavier cuts of petroleum distillate fractions in the gas oil and lubricating oil range - heavy hydrocarbon mixtures having initial boiling points greater than 150ºC (300ºF), such as heavy crude oils, petroleum distillates, residues, and synthetic mixtures. 

Individual crude oil quality tests are also available on an individual basis. Contact Intertek for more details.

Typical listing of Crude oil assay tests*:


  • Atmospheric distillation, D2892
  • Vacuum pot distillation, D5236
  • Distillation,  D86, D1160
  • Distillation, simulated, D2887, D7169
  • Specific gravity, API, D5002, D2598, D4052, D1298
  • Total sulfur,  D4294, D2622, D5453
  • Mercaptan sulfur, H2S, UOP 163
  • Total acid number, TAN, D664, D974
  • Vapor pressure, D323, D5191
  • GC analysis, DHA, PIONA, Hydrocarbon Typing, D6730, D5443, D2425
  • Naphthalene, D1840
  • Smoke point, D1322
  • Freeze point D2386, D5972
  • Cloud point,D2500, D5771
  • Pour point, D97, D5949

  • Total nitrogen, D4629, D5762
  • Basic nitrogen, UOP 269
  • Bromine number, D1159
  • Carbon, hydrogen, D5291
  • Aniline point, D611
  • Refractive index, D1747
  • Viscosity @ multiple temps, D445, D7042
  • Carbon residue, D189, D4530
  • Heat of combustion, D240
  • Asphaltenes,  D6560, IP-143
  • Metals, D5708, D5863, IP-501
  • Ash, D482
  • Chlorides, D4929, UOP 779, UOP 588
  • Anions, D4327
  • Flash point, D56, D92, D93
  • Penetration, D5
  • Wax content and characteristics
  • *Additional crude oil assay tests are available, depending upon client needs and requirements.
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