Petroleum classification physical properties. Petroleum or crude oil Naturally occurring & flammable liquid Complex mixture of hydrocarbons & other organic compounds Found in geologic formations beneath the Earth’s surface The term ‘petroleum’ first used in the treatise De Natura Fossilium published in 1546- Georg Bauer (German mineralogist). Derived from the Latin word petra oleum, meaning “stone oil” Oil and gas provide about 60% of all the energy used by the society today

1. PETROLEUM
CLASSIFICATION & PHYSICAL PROPERTIES
ASHIKRAJ RS
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2. INTRODUCTION
 Petroleum or crude oil
 Naturally occurring & flammable liquid
 Complex mixture of hydrocarbons & other organic compounds
 Found in geologic formations beneath the Earth’s surface
 The term ‘petroleum’ first used in the treatise De Natura Fossilium
published in 1546- Georg Bauer (German mineralogist).
 Derived from the Latin word petra oleum, meaning “stone oil”
 Oil and gas provide about 60% of all the energy used by the society
today
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3. Petroleum……..
 Petra oleum, meaning “stone oil”.
 Color –
 Found in Sedimentary strata .
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4. Formation of petroleum……
 Petroleum is a fossil fuel.
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6. Migration of petroleum rocks only ends when it came to a reservoir rock
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7.  Liquid petroleum can be transport easily
 It can be use both as a fuel as well as a lubricant
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8. PETROLEUM CLASSIFICATION
 Petroleum- mineral oil, crude oil, crude petroleum, crude or simply
oil
 Varies in appearance and nature
 No two petroleum are exactly alike
 Organic in origin
 Occurs in solid, liquid and gaseous forms
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9. SOLID FORM
 Found separated from the liquid components
ASPHALTS
 Leaves the liquid constituents as natural asphalts on reaching the surface
 ‘Trinad’, famous asphalt lake
 Hard type of asphalts are - Vintatite, Galsonite and Ozokerite
 Readily mistaken as coal
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Fig 1. Pitch lake, Trinad
Source: Google images

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Fig 2. Asphalt
Source: Google images

12. 12WAX
 Deposited as veins of wax in the rocks in some location in Europe &
USA
 Ozokerite, a wax is widely used in industry as wax with high melting
point
Fig 3. Wax
Source: Google images

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LIQUID FORM
 Crude oil
Fig 4. Crude oil
Source: Google images

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GASEOUS FORM
 Natural gas
 A large part of gas is associated with petroleum
 It is separated from the petroleum when it reaches the surface of the earth
 Sometimes it get separated naturally underground

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TAR SAND
 Semi-solid petroleum bearing sand
 Northern Alberta in Canada has a unique deposit covering many square miles with
a reserve of about hundreds of million barrels; world’s largest but of little use
 Too viscous to flow
 A ton of sand gives a bucket of petroleum
 Heated to obtain a material very similar to ordinary crude oil
 Similar to kerogen or oil shale
 Heavier portion of the crude oil from which lighter fractions have been evaporated

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Fig 5. Tar sand in Northern Alberta, Canada
Source: Google images

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Fig 6. Tar sand
Source: Google images

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OIL SHALE
 Oil bearing shale
 Exist in enormous quantities in Colorado, Utah and Wyoming states of USA
 On heating gives various amounts of heavy viscous oil up to about two barrels per
ton of shale
 Economical process for the extraction of oil from shale has not yet developed
 Intermediate phase in the transformation of the original source material in to crude
oil
 Often called kerogen

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Fig 7. Oil shale
Source: Google images

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PHYSICAL PROPERTIES
☻ Petroleum is a mixture of hydrocarbons
☻ Based on the type and relative proportion of the hydrocarbon and
impurities (S,N) properties varies
☻ Migration, accumulation and recovery of oil

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Important physical properties include
⁂ COLOUR
⁂ ODOUR
⁂ SPECIFIC GRAVITY
⁂ VISCOSITY
⁂ FLASH POINT
⁂ OPTICAL ACTIVITY
⁂ BOILING POINT
⁂ FLUORESCENCE

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COLOUR
☻ Colour varies; colourless to light yellow, red, green, brown and black
☻ Thin layer- Less intense colour ( brown in dark oils)
☻ Higher gravity crude oil- amber green
Lower gravity crude oil- dark brown to black
☻ Appear different in reflected light and transmitted light
☻ Brown oil, green colour in reflected light
☻ UV light gives fluorescence for both transmitted and reflected light;
used to test core samples and drilling mud
☻ Most of the pure hydrocarbons are colourless; coloured by oxidation
by the addition of O2 to colourless leucobases
☻ Determined with ‘Saybolt calorimeter’

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ODOUR
☻ Determined by composition
☻ Paraffin’s and naphthenes have gasoline like odour
☻ Undersaturated hydrocarbons containing N compounds and S give
unpleasant odour
☻ For eg., Mercaptans containing S give warning smell helps to detect
leakage in pipe lines carrying commercial natural gas
☻ Some oils of East India, California and Russia contain aromatic
compounds which impart pleasant odour

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SPECIFIC GRAVITY
☻ Most commonly measured physical property
☻ Classifying oil in a rough and ready formation and for determining the selling
price
☻ It is the ratio of the weight of a given volume of oil to the weight of an equal
volume of distilled water both at specified temperature
☻ An index to the value of oil; lighter oils have greater value because they
contain large quantity of volatiles and other valuable products
☻ Oil is lighter than water, therefore sp.gr. is expressed in decimals or fractions
Gasoline = 0.7796, Kerosene = 0.8109

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☻ API gravity scale- United States; Baume scale- Europe
☻ API gravity varies with changes in depth, temperature, age of rocks, impurities
and with geosynclinal history of different areas
☻ API gravity value; 10= water; >10= lighter oil; <10= denser oil
☻ Sp.gr. of oil increases with temperature; decreases with the amount of S
compounds
☻ Density is measured by putting a Hydrometer calibrated upon the stem

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VISCOSITY
☻ Ability of a liquid to flow
☻ Time necessary for a specific volume of oil at a definite temp to flow through an
unit opening
☻ Standardized viscometers are used
☻ Crude petroleum varies greatly in viscosity; light oils very mobile & heavy oils
highly viscous
☻ Depends on the chemical composition and amount of dissolved gas in the
petroleum
☻ Greater the no. of C atoms in a hydrocarbons series the greater will be its viscosity
☻ More gas in solution and higher the temp. the viscosity will be less

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FLASH POINT
☻ Below a certain temperature the vapour or one of the volatile products given off
by the crude oil will not burn, but as temp. is raised more vapour is released until
an inflammable mixture with air is formed
☻ The lower temperature at which this takes place is called the Flash point of the
liquid concerned

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OPTICALACTIVITY
☻ The power of rotating the plane of polarization of polarized light
☻ Measured using Polariscope in degree per millimetre and the avg range is 0 – 1.2º
☻ Dextrorotatory- if the plane is rotated to the right
Levorotatory – if the plane is rotated to the left
☻ Caused by the presence of cholesterol, found in both vegetable and animal matter
and has the formula C26-H45-OH
☻ Oil of inorganic origin would not show optical activity
☻ Occurrence of optical activity in petroleum is therefore a strong argument for the
generation of petroleum from the organic remains

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Schematic of a polarimeter showing the principles
behind its operation. Unpolarised light is passed
through a polarising filter before travelling through a
sample. The degree of rotation of polarisation is
determined by a second, rotatable filter

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BOILING POINT
☻ Variable and depends on composition
☻ BP is high for an oil of low API gravity because of large proportion of
hydrocarbon with a high BP and vice versa

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FLUORESCENCE
☻ All crude oil show fluorescence or glow of varying degree under UV light
☻ Aromatic oils are the most fluorescent
☻ Fluorescent colours range from yellow through green to blue
☻ Used in logging of wells to locate oils in core cuttings and drilling mud
☻ Aging reduces fluorescence and is helpful in identifying fresh oil
☻ In Petroleum industry it is also used to determine the grade and purity of
crude oil and its refined products and to identify specific zones from
which a well is producing

32. CONCLUSION
• Petroleum is classified into solid, liquid, gaseous forms, tar sand and oil shale
• Important physical properties of petroleum include colour, odour, specific
gravity, viscosity, flash point, optical activity, boiling point and fluorescence
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