The Formation of Oil (Part 1 of 2)

Dead organic matter must lie in either stagnant, oxygen-free waters at the bottom of the sea until buried or be buried quickly after death and achieve a concentration of one to three percent by weight to become a future oil reservoir, although this concentration can be as high as ten percent.  The next step is burying the organically rich sediment deep enough to generate the temperature and pressure necessary to transform organic matter to oil. 

With 7,000 feet of overburden, the pressure is sufficient to raise the sediment’s temperature to 150 degrees Fahrenheit, the minimum to produce a heavy and generally undesirable grade of crude oil.  Preferred light crudes are produced as one approaches 18,000 feet and 300 degrees Fahrenheit.  Beyond 18,000 feet, the temperature and pressure are sufficient to transform oil to graphite and natural gas.  The oil window is 7,000 – 18,000 feet below the surface of the earth, meaning that sediments at river mouths must be buried between 1.5 – 3.5 miles of debris to produce oil by either the ocean bottom sinking or the surrounding land mass rising or a combination of both.

The properties of the oil depend on the type of organism, its concentration, depth of burial and the nature of the surrounding sediment.  Oil properties vary from one field to another and no two fields have exactly the same properties.  Commercial grades of crude are really a mix of oil from different oil fields in the same region that have similar properties.  A few are from different oil fields with dissimilar properties such as Urals, a specified mix of light sweet crude from western Siberia and heavy sour crude from the Ural region of Russia.

Heartland Energy Colorado is one of the top hydrocarbon-based energy providers in the USA. They have many drilling locations throughout the country and remain one of the top producers of US oil & gas companies. For more information on Heartland Energy Colorado, see Heartland Energy Development Corporation online.

(Source: "Energy for the 21st Century," Nersesian)