Oil and gas production handbook An introduction to oil and gas production

White and black oils: The above products are often called white oils, and 
the fractions are generally available from the atmospheric distillation 
column. The remaining fraction below are the black oils, which must be 
further separated by vacuum distillation due to the temperature restriction of 
heating raw crude to no more than 370-380 °C. This allows the lighter 
fractions to boil off at a lower temperatures than with atmospheric 
distillation, avoiding overheating. 
 
Lubricating oils, or mineral base lubricating oil (as opposed to synthetic 
lubricants), form the basis for lubricating waxes and polishes. These 
typically contain 90% raw material with carbon numbers from 20 to 50 and a 

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fraction boiling at 300-600 °C. 10% additives are used to control lubricant 
properties, such as viscosity. 
 
Fuel oils is a common term encompassing a wide range of fuels that also 
includes forms of kerosene and diesel, as well as the heavy fuel oil and 
bunker  that is produced at the low end of the column before bitumen and 
coke residues. Fuel oil is graded on a scale of 1 to 6 where grade 1 and 2 is 
similar to kerosene and diesel, 3 is rarely used anymore. 4-6 are the heavy 
fuels, also called Bunker A, B and C, where B and C are very high viscosity 
at normal ambient temperatures and requires preheating to about 100 °C 
and 120 °C respectively, before it flows enough to be used in an engine or 
burner. Fuel oil grade 4 does not require preheating and is sometimes mixed 
with off spec products, such as tank residue and interface liquid from 
multiphase pipelines or with grade 2 fuel oil to achieve low-enough viscosity 
at ambient temperatures. Fuel oil 6 is the lowest grade, its specification also 
allows 2% water and 0.5% mineral soil and is consumed almost exclusively 
by large ships in international waters, where pollutants such as sulfur is less 
regulated. 
 
Bitumen and other residues like coke and tar has carbon numbers above 70 
and boiling points above 525 °C. Low sulfur coke can be used for anodes in 
the metals industry (aluminum and steel) after processing (calcining). The 
remainder is a problem fuel, because of high sulfur content and even higher 
CO
2
 emissions than coal (typically 15% higher). Bitumen in the form of 
asphalt boiling above 525 °C is used for roofing and road paving. Asphalt 
concrete pavement material is commonly composed of 5% asphalt/bitumen 
and 95% stone, sand, and gravel (aggregates). 
6.3  Upgrading and advanced processes 
The Refinery make up differs from an upstream plant, in that the overall site 
is divided up in to process types or 'units'. The refining plant type processes 
are generally licensed, and a license is required to build and operate one of 
these. Each license will be the same but scaled to meet the processing 
capacity in tons per day. A full explanation of these processes is beyond the 
scope of this book, but a non-exhaustive description is given below. 
 
The following figure gives a more detailed process flow diagram of an actual 
modern refinery. It shows the extent of treatment that takes place after initial 
fractional distillation, to improve fuel yield and functional properties, and an 
explanation of why modern gasoline at the pump contains less than 20% raw 
gasoline straight from the column. Additional processes may also be 
included, e.g., for crude pre-treatment to be able to source lower quality 
crudes with less processing at the production site.   

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