7.1 Introduction

• Defintion: The word petroleum comes from the Greek  for “rock oil” or “crude oil”.  In Japan in the 7th century it was known as “burning water”.

• The word gasolene was first used in 1865 and the shortened form, “gas” in about 1905. The word "petrol" was first used to descibe the refined product in the early 1890s.

• Where Found: It is found in formations of porous rock located in some parts of the upper strata of the earth’s crust. It can also be found mixed with sand and shale.

• Hydrocarbon: Petroleum consists of a complex mixture of hydrogen and carbon molecules in varying ratios or “fractions”. Refining is the separation of these “fractions” into useful products.

• Refining: The lighter fractions (heaviest first) produce heating oils, diesel fuel, kerosene/paraffin, petrol, and the volatile petroleum, butane and propane gases. The densest fractions produce tar and asphalt.

• Current Use: 84% of petroleum is used to produce fuel oil and petrol/gasoline. The remaining 16% is used mainly in the production of fertilisers, plastics, solvents and pesticides.