· It provides lubricants and raw materials for a number of chemical industries.
· Products include kerosene, diesel, petrol, aviation-fuel, synthetic rubber, synthetic-fibre, thermoplastic resins, benzene-methansol, polystertene, acrylates, detergents, aromatics, gasoline, carbon-black, dyes, colours, food-colours, pigments, explosives, printing ink, film-photography, greases, cosmetics, paints, lubricant oils, paraffin, and wax.
· Crude oil is obtained mainly from the sedimentary rocks of marine origin. In India, crude oil is found in the sedimentary rocks of the Tertiary period
· Normally it does not occur at its place of formation.
· Being lighter than water, crude oil overlain with gas, gets accumulated in the anticlines above the water surface.
In India, origin:
· 1860- mergherita (upper assam) – first time oil discovered by assam railway and trading company .
· 1889- oil was discovered in digboy .
· 1917 – badarpur(assam) .
· 1954- production of oil was started in naharkatiya region.
· 1956- ONGC .
· 1961- gulf of cambay (khambat) –discovered by ONGC .
· 1976 –bombay high - discovered by ONGC .
In India, the petroleum and natural gas has been discovered in the following ten basins:
· 1. The Upper Assam Basin (60,000 sq km)
· 2. The Western Bengal Basin (60,000 sq km)
· 3. The Western Himalayan Basin (100,000 sq km)
· 4. The Rajasthan Saurashtra-Kachchh Basin (95,000 sq km)
· 5. The Northern Gujarat Basin (140,000 sq km)
· 6. The Ganga Valley Basin (385,000 sq km)
· 7. The Coastal Tamil Nadu, Andhra & Kerala Basin (75,000 sq km)
· 8. The Andaman and Nicobar Coastal Basin (2000 sq km)
· 9. Offshore of the Khambat, Bombay High & Bassein (2000 sq km)
Crude-Oil Producing Regions in India :
1. The Western Coast Offshore Oilfields
The Bombay High Oilfields :
· largest petroleum production oilfield contributing over 65 per cent of the total production of crude oil.
· lies about 176 km to the south-west of Bombay.
· has about 35 million tonnes of crude oil and about 40,000 million cubic metres of natural gas.
· started in 1976.
· Owing to over exploitation, the production of this oil-field is declining fast.
· lies to the south of Bombay High.
· occurs at a depth of over 1900 metres.
· rich deposits of oil and natural gas.
Aliabet Oilfield :
· located about 45 km to the south of Bhavnagar.
2. The Gujarat Coast
· This is the second largest oil producing area of the country.
· Its main oilfields are in Ankleshwar, Cambay-Luni area and Ahmadabad-Kalol region.
· Situated in the district of Bharauch, it stretches over an area of about 30 sq km.
· The oil of this region belongs to the Eocene period.
· started in 1961.
· rich in gasoline and kerosene.
· The crude oil from this region is sent to the Koyali petroleum refinery.
(ii) Cambay-Luni Region:
· lies about 60 km to the west of Vadodara.
· started in 1958.
· The estimated reserves of crude-oil are over 30 million tonnes.
· very light with a sulphur content of less than 0.1 per cent.
(iii) The Ahmadabad-Kalol Region:
· lies to the north of Gulf of Khambat (Cambay) around the city of Ahmadabad and extends up to Mehsana. Kalol, situated about 25 km to the north of Ahmadabad is an important oilfield of the region.
· started in 1961.
· supplied mainly to the Koyali refinery.
3.The Eastern Coast:
· Oil-fields Petroleum and natural gas have been discovered in marine delta regions of Mahanadi, Godavari, Krishna, and Kaveri rivers.
· The Rawa field in the Godavari-Krishna offshore is expected to produce about 3 million tonnes of crude-oil annually.
· Petroleum has also been discovered in the Kaveri delta.
· In addition to these, crude oil has been discovered in the Bilaspur Tehsil of Rampur District of Uttar Pradesh, Jawalamukhi area of Punjab, and in the Barmer District of Rajasthan.
· found on the offshore of Andaman and Nicobar, Gulf of Mannar, Baleshwar coast, Punjab, Haryana and Uttar Pradesh.
4. The Brahmaputra Valley:
· Crude oil was first discovered in the Brahmaputra valley.
· spread from the Dehang Basin up to the Surma valley.
· The main oil producing wells, however, lie in the Dibrugarh and Sibsagar districts of Upper Assam.
· Some of the important oil producing centres of this region are given below:
(i) The Digboi Oilfield Stretching over an area of about 15 sq km, the Digboi oilfield is one of the oldest oil-fields of the country.
· belongs to the Eocene and Miocene periods.
· There are 85 oil wells in this region.
· Most of the oil is sent to the refinery of Digboi.
Natural gas :
· Exploration –by- ONGC
· potential- about 450 billion cubic metres .
· 75%- lies in Bombay High and the bassein oil fields.
· 7%-andhra Pradesh
· 6%- assam
· Others- TN , HP ,PUNNJAB
· Largest share of natural gas is consumed in the production of chemical fertilizer (about-40%).
· 30% - power generation ,
· 10%- L.P.G (cooking gas)