Theories of origin of petroleum : Theories should describe the following characteristics related with petroleum,
Its association along with brine or sodium chloride solution. The presence of nitrogen and sulphur elements in it. The presence of haemin and chlorophyll in it. It is optically active procedure. Three very significant theories are as follows.
(a) Inorganic theory or Mendeleeff's carbide theory
(b) Organic theory or Engler's theory
(c) Modern theory