Crude Oil Assay Quick Reference

Typical API gravity, sulfur content, TBP cut yields, and contaminant levels for representative crude grades.

Crude Assay

Representative Crude Oil Assay Quick Reference · Sources: EIA Crude Oil Assay database; BP Statistical Review; Haverly Systems H/CAMS. Values are typical; actual assay varies by batch.

Crude Name	Region	API Gravity	Sulfur (wt%)	TAN (mg KOH/g)	Pour Pt (degF)	Viscosity @ 104F (cSt)	Classification	Typical Notes
West Texas Intermediate (WTI)	USA - Permian	39.6	0.24	0.1	-30	3.5	Light Sweet	US benchmark; high naphtha, low S, good for gasoline refineries
Brent Blend	North Sea	38.3	0.37	0.1	-22	5	Light Sweet	Global benchmark; similar to WTI
Dubai/Oman	Middle East	31	2	0.2	-8	9	Medium Sour	Asia benchmark; high S, requires HDS
Arab Light	Saudi Arabia	33.4	1.8	0.05	-35	7.5	Medium Sour	Global export grade; balanced yield
Arab Heavy	Saudi Arabia	27.6	2.85	0.1	-20	22	Heavy Sour	High S, requires deep conversion (coker/HCU)
Bonny Light	Nigeria	35.4	0.14	0.2	15	6	Light Sweet	Low S, high naphtha, waxy pour point
Urals	Russia (blend)	31.4	1.37	0.3	-15	10	Medium Sour	Russian export; moderate S
Maya	Mexico	21.8	3.36	0.4	-5	80	Heavy Sour	Heavy sour; coker/HCU/asphalt refiners
WCS (Western Canadian Select)	Canada - AB	20.5	3.5	1.5	-15	150	Heavy Sour (Bitumen)	Diluted bitumen (dilbit); very heavy, high TAN
Eagle Ford Shale	USA - TX	47	0.1	0.15	-40	1.8	Ultra-Light Sweet	Condensate-rich; limited bottoms
Bakken Shale	USA - ND	42.5	0.15	0.15	-35	2.8	Light Sweet	Shale crude; high API, low S
Mars Blend	USA - GOM	29	2	0.3	-5	13	Medium Sour	Offshore US; sour
Tapis	Malaysia	45.5	0.03	0.05	60	3.5	Light Sweet (waxy)	Very waxy; high pour point
Daqing	China	32	0.11	0.15	85	20	Paraffinic (waxy)	Extremely waxy; requires heated handling
Basrah Light	Iraq	31.1	2.93	0.15	-20	12	Medium Sour	High S
Duri	Indonesia	21.1	0.18	0.5	60	120	Heavy Sweet (waxy)	Heavy, low S, waxy
Classification Rules of Thumb:
API classification: Light > 31.1, Medium 22.3-31.1, Heavy < 22.3, Extra-Heavy < 10 (SG > 1.0).
Sulfur classification: Sweet < 0.5 wt%, Intermediate 0.5-1.5%, Sour > 1.5 wt%.
TAN greater than 0.5 mg KOH/g is corrosive in high-T units (vac, crude/vac bottoms); require upgraded metallurgy (5Cr/9Cr/317L).
Heavy sour crudes require deep conversion: delayed coker or hydrocracker + HDS/HDT.
Shale/tight oil is ultra-light; creates imbalance (low VGO/bottoms) for complex refineries.
Waxy crudes (high pour point): require heated tankage/pipelines or diluent (condensate, kerosene).
Classification boundaries per API MPMS Ch. 11.1 (gravity) and common industry practice (S, TAN).

Source: Crude_Oil_Assay_Quick_Ref_v1.xlsx

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