Importance of petroleum :
(i) Petroleum is the major energy source in India.
(ii) It provides fuel for heat and lighting.
(iii) It provides lubricant for machinery.
(iv) It provides raw material for a number of manufacturing industries.
(v) Petroleum refineries act as nodal industry for synthetic, textile, fertilizer and chemical industries
Its occurrence :
(i) Most of the petroleum occurrences in India are associated with anticlines and fault traps.
(ii) In regions of folding, anticline or dams, it occurs where oil is trapped in the crest of the upfold.
(iii) Petroleum is found in fault traps between porous and non-porous rocks.