Product overview
Base oils are produced by refining the appropriate crude oil fractions, either by solvent refining or by hydroprocessing. They are characterised by viscosity, viscosity index (the measure of how viscosity changes with temperature), pour point, flash point and colour.
The API group classification reflects purity and performance: Group I is solvent-refined; Group II and Group III are hydroprocessed, offering higher saturate content, lower sulphur and, for Group III, a high viscosity index. Individual cuts are described by a viscosity designation such as SN 150, SN 500 or a bright stock.
Typical specifications
| Classification | API Group I / II / III base stocks |
|---|---|
| Common cuts | SN 150, SN 500, SN 150BS / bright stock, per grade |
| Kinematic viscosity at 40 °C | grade dependent |
| Viscosity index | approx. 95–105 (Group I/II); 120+ (Group III) |
| Pour point | typically -9 °C or lower, per grade |
| Flash point | typically above 200 °C, per grade |
| Sulphur | higher in Group I; low in Group II/III |
| Colour (ASTM D1500) | per grade |
Indicative typical values shown for orientation only. Exact quality is cargo-dependent and the final contractual specification, as confirmed in the sales agreement and verified by independent inspection, prevails.
Commercial relevance and typical uses
Base oils are the foundation of finished lubricants, usually making up the majority of a blend before additives. They are used by lubricant blenders to manufacture engine oils, industrial and hydraulic oils, greases, metalworking fluids and process oils.
Group selection follows the finished product's performance requirements: Group I remains in use for many industrial oils, while Group II and III are preferred where higher oxidation stability and viscosity index are needed, such as in modern engine oils.
Quality and independent inspection
An independent inspector samples base oil and tests viscosity, viscosity index, pour point, flash point, colour and related parameters against the agreed grade, issuing a certificate of quality, and verifies the shipped quantity. Clean handling matters because base oils are sensitive to contamination. 3FB coordinates inspection; SGS and Intertek are given only as examples of firms used in the sector, not partners.
Shipping and logistics
Base oils move in clean tankers, in flexitanks within containers, or in new drums and IBCs for smaller parcels. 3FB trades on FOB terms, where the buyer arranges carriage, and on CIF terms, where 3FB arranges freight and insurance to the discharge port, as explained in FOB versus CIF.
A delivery window is agreed as a laycan, and tank or packing selection accounts for cleanliness to protect specification. See shipping and logistics.
Trade documentation
A base oil cargo carries the bill of lading, certificate of origin, certificate of quality and certificate of quantity from the inspector, a packing list where drums or IBCs are used, and the commercial invoice, with payment commonly under a documentary letter of credit.
The bill of lading and letter of credit notes cover these instruments.
Buyer inquiry process
To request an indication, state the group and viscosity cut (for example Group II SN 150 or SN 500), the volume, the packing (bulk, flexitank, drums or IBCs), the delivery terms (FOB or CIF with the port), the laycan and the payment instrument. The desk reviews feasibility and responds with an indicative offer, subject to confirmation.
KYC and compliance review precede any definitive agreement. Start at the trading desk.