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In the international petroleum industry, crude oil products are traded on various oil bourses based on established chemical profiles, delivery locations, and financial terms. The chemical profiles, or crude oil assays , specify important properties such as the oil's API gravity .
API gravity is graduated in degrees on a hydrometer instrument. API gravity values of most petroleum liquids fall between 10 and 70 degrees. In 1916, the U.S. National Bureau of Standards accepted the Baumé scale, which had been developed in France in 1768, as the U.S. standard for measuring the specific gravity of liquids less dense than water.
In other words, oil with a density greater than 1000 kg/m 3 (or a specific gravity greater than 1) and a reservoir viscosity of more than 10,000 centipoises. [3] [5] Heavy oils and asphalt are dense nonaqueous phase liquids (DNAPLs). They have a low solubility and a viscosity greater than, and density higher than, water. [6]
A United States Navy Aviation boatswain's mate tests the specific gravity of JP-5 fuel. Relative density, also called specific gravity, [1] [2] is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material.
The specific gravity of gasoline ranges from 0.71 to 0.77, [14] with higher densities having a greater volume fraction of aromatics. [15] Finished marketable gasoline is traded (in Europe) with a standard reference of 0.755 kilograms per liter (6.30 lb/U.S. gal), (7,5668 lb/ imp gal) its price is escalated or de-escalated according to its ...
The clear cut definition of light and heavy crude varies because the classification is based more on practical grounds than theoretical. The New York Mercantile Exchange (NYMEX) defines light crude oil for domestic U.S. oil as having an API gravity between 37° API (840 kg/m 3) and 42° API (816 kg/m 3), while it defines light crude oil for non-U.S. oil as being between 32° API (865 kg/m 3 ...
Thus, the API gravity or specific gravity is widely used for the classification of crude oils, based on a scheme proposed by the American Petroleum Institute (Table 1). A high API value >30 means a light crude with paraffinic character; a low API value means a heavy crude with increasing aromatic character. Table 1.
The Wobbe index is expressed in MJ/Nm³ (where 'Nm³' indicates'm³ in Normal conditions), or sometimes in BTU/scf.In the case of natural gas (molar mass 17 g/mol), the typical heating value is around 39 MJ/Nm³ (1,050 BTU/scf) and the specific gravity is approximately 0.59, giving a typical Wobbe index of 51 MJ/Nm³ (1,367 BTU/scf).