Extra Heavy Crude Oil—also known as bitumen-like crude, ultra-heavy crude, or tar-grade crude—is a type of petroleum that has very high density, extremely high viscosity, and low API gravity (below 10°). It is so thick at room temperature that it behaves like asphalt or semi-solid bitumen.
This crude usually requires thermal methods, steam injection, or dilution with lighter hydrocarbons to enable pumping and refining.
It is commonly sourced from Venezuela’s Orinoco Belt, Canada’s oil sands, and heavy oil basins around the world.
Classification
| Parameter | Value |
|---|---|
| API Gravity | < 10° API |
| Density @15°C | >1.00 g/cm³ |
| Viscosity @40°C | >10,000 cSt |
| Flow Behavior | Non-Newtonian (often viscoplastic) |
Bitumen-like crude does not flow naturally and requires thermal, chemical, or mechanical assistance.
Chemical Composition
| Component | Typical Content |
|---|---|
| Asphaltenes | 15–35% |
| Resins | 20–40% |
| Aromatics | 20–30% |
| Saturates | 5–15% |
Dominated by high molecular weight polyaromatic compounds.
Elemental Composition
| Element | Typical Range |
|---|---|
| Carbon | 80–85% |
| Hydrogen | 8–10% |
| Sulfur | 3–7% |
| Nitrogen | 0.5–1.5% |
| Oxygen | 1–3% |
| Metals (Ni, V, Fe) | 100–2,000 ppm |
Key Physical Properties
| Property | Typical Value |
|---|---|
| API Gravity | 6°–10° |
| Density | 1.00–1.05 g/cm³ |
| Viscosity @40°C | 10,000–1,000,000 cSt |
| Pour Point | +30°C to +60°C |
| Softening Point | 50–90°C |
| Flash Point | >100°C |
| Conradson Carbon | 15–25 wt% |
| Sulfur Content | Very High |
Mechanical Properties (Handling & Transport)
Rheology
Non-Newtonian (shear-thinning)
Exhibits yield stress
Requires thermal heating (>60°C) or dilution
Pumpability
Poor without:
Diluent blending (naphtha/condensate)
Heating
Emulsification
High torque pumps required
Adhesion & Abrasion
Highly adhesive
Entrained solids cause erosive wear
Severe fouling potential
Strengthening & Metallurgical Behavior (Refinery & Pipeline Impact)
Extra-heavy crude has the most aggressive metallurgical impact of all crude types.
| Mechanism | Effect |
|---|---|
| Sulfidation | Severe at 250–450°C |
| Naphthenic Acid Corrosion (NAC) | Extreme |
| High-Temperature Hydrogen Attack | Elevated |
| Erosion-Corrosion | Very high |
Metallurgical Requirements
High-Cr steels (9–12% Cr)
Cr-Mo-V alloys
Duplex & Super Duplex Stainless Steel
Inconel / Hastelloy (critical units)
Coke & Metal Deposition
Rapid coke laydown
Vanadium pentoxide corrosion
Catalyst sintering & poisoning
Key Characteristics
Extremely high viscosity
Asphalt-like behavior
High sulfur & metal content
Very high carbon residue
Low hydrogen-to-carbon ratio
Requires upgrading before marketability
Refining & Processing Properties
Primary Processing
Atmospheric distillation → minimal yields
Vacuum distillation → heavy residue dominant
Upgrading Technologies
| Process | Purpose |
|---|---|
| Delayed Coking | Convert residue → coke + distillates |
| Fluid Coking | Continuous coke removal |
| Hydrocracking | Hydrogen addition |
| Solvent Deasphalting | Remove asphaltenes |
| Visbreaking | Reduce viscosity |
| Gasification | Syngas production |
Hydrogen Demand
Extremely high
Requires:
Hydrogen plants
Gasification units
Available Forms
Natural bitumen
Diluted bitumen (Dilbit)
Synbit (synthetic crude + bitumen)
Emulsified bitumen
Upgraded synthetic crude oil (SCO)
Solid asphalt blocks
Applications
Energy & Fuel
Power generation fuel (after upgrading)
Marine bunker fuels (with treatment)
Construction
Road asphalt
Roofing membranes
Waterproofing materials
Petrochemical & Industrial
Carbon black feedstock
Petroleum coke
Gasification feedstock (H₂, NH₃, methanol)
Advantages of Extra-Heavy / Bitumen-Like Crude Oil
Massive global reserves
Low acquisition cost
Long-term energy security
Ideal for integrated refinery-petrochemical complexes
Strategic feedstock for asphalt & coke industries
Why Choose Extra-Heavy Crude Oil?
Strategic Perspective
Unlocks stranded hydrocarbon reserves
Reduces dependence on light crude imports
Economic Perspective
High margins for complex refineries
Value uplift via upgrading
Low feedstock cost
Industrial Perspective
Essential for infrastructure development
Reliable asphalt supply
Major Global Sources
Venezuelan Orinoco Belt
Canadian Oil Sands (Athabasca)
Russian Bitumen Deposits
Middle East Heavy Oil Fields
Environmental & Operational Considerations
High CO₂ footprint
Water-intensive processing
Advanced waste management required
Strict emissions control mandatory
Extra-heavy or bitumen-like crude oil is the most challenging yet resource-rich form of petroleum. While it demands:
Advanced metallurgy
High CAPEX
Complex upgrading
…it offers:
Long-term supply stability
Strategic industrial value
High return potential for technologically advanced operators