Formation of Petroleum and Mineral Oil, Distribution of Petroleum and Mineral Oil in India, On-shore and Off-Shore Oil Production in India.

Petroleum and Mineral Oil

• Petra == rock; Oleum == oil.
• Petroleum or Mineral oil is obtained from sedimentary rocks of the earth.
• Petroleum fuels on burning gives little smoke and leaves no ash. So they are better than coal.

Constituents of Petroleum and Mineral Oil

• 90 to 95 per cent Hydrocarbons.
• 5 – 10% organic compounds containing oxygen, nitrogen, sulphur and traces of organometallic compounds.

Formation of Petroleum and Mineral Oil

• All sedimentary rocks do not contain oil.
• An oil reservoir must have three prerequisite conditions.

1. Porosity [tiny gaps in soil] so as to accommodate sufficiently large amounts of oil;
2. permeability [allowing liquids or gases to pass through it.] to discharge oil and/or gas when well has been drilled;
3. the porous sandstone beds or fissured limestone containing oil should be capped below by impervious beds [not allowing fluid to pass through].

• Most of the oil gets collected in the anticlines or fault traps.
• Oil on a commercial scale is usually found in crests of anticlines [where the sedimentary rock strata are inclined and folded].

Distribution of Petroleum and Mineral Oil in India

• Process began in tertiary period [3 million years ago].
• Most of the oil reserves in India are associated with anticlines and fault traps in the sedimentary rock formations of tertiary times.
• In tertiary period, aquatic life was abundant in various forms, especially the minor microscopic forms of flora and fauna.
• Conditions for oil formation were favourable especially in the lower and middle Tertiary period.
• Dense forests and sea organisms flourished in the gulfs, estuaries, deltas and the land surrounding them during this period.

Extent of Oil Bearing Strata in India

• 1 lakh sq km or 42 per cent of India covered with sedimentary rocks.
• 10 lakh sq km form marine basins of Mesozoic and Tertiary times.
• Total continental shelf of probable oil bearing rocks amounts to 2 lakh sq km.
• The total sedimentary area including both on shore and offshore comprises 27 basins.
• Mumbai High, the Khambhat Gulf and the Assam are the most productive areas.

On-shore Oil Production In India

• Brahmaputra valley of north-east India.
• Barmer area of Rajasthan.
• Gujarat coast in western India.
• Cauvery on-shore basin in Tamil Nadu.
• Andhra Pradesh has both on-shore and offshore oil reserves.

Assam Oilfields

• Oldest oil producing state in India
• The main oil bearing strata extend for a distance of 320 km in upper Assam along the Brahmaputra valley.
• Oilfields of Assam are relatively inaccessible and are distantly located from the main consuming areas.
• Oil from Assam is therefore, refined mostly in the refineries located at Digboi, Guwahati, Bongaigaon, Barauni and

Gujarat Oilfields

• Ankleshwar, Khambhat or Lunej, Ahmedabad and Kalol, Nawgam, Kosamba, Kathana, Barkol, Mahesana and Sanand are important oilfields of this region.
• Ankleshwar: Oil from this field is sent to refineries at Trombay and Koyali.

Rajasthan Oilfields

• One of the largest inland oil discoveries was made in Banner district of Rajasthan.
• Other important discoveries == Mangala oil field, Sarswati and Rajeshwari.
• Rajasthan is the largest on shore oil producing state of India.

Off-Shore Production in India

Western Coast

• Mumbai High, Bassein and Aliabet.
• Mumbai High: 1974; rock strata of Miocene age.
• Sagar Samrat, Bassein: south of Mumbai High.
• Aliabet: Aliabet island in the Gulf of Khambhat.

Eastern Coast

• The basin and delta regions of the Godawari, the Krishna and the Cauvery rivers hold great potential for oil and gas production.
• The Rawa field in Krishna-Godawari off-shore basin is an important one.
• The Narimanam and Kovilappal oilfields in the Cauvery on-shore basin are also important.

Petroleum Refining

• India’s first oil refinery started working way back in 1901 at Digboi in Assam.
• 1954: another refinery at Tarapur (Mumbai).
• Refinery hub and refining capacity exceeds the demand. Excess refined oil and other petroleum products are exported.
• Oil from wells is transported to nearest refineries through pipelines.

Advantages of Pipeline

• Ideal to transport liquids and gases.
• Pipelines can be laid through difficult terrains as well as under water.
• It needs very little maintenance.
• Pipelines are safe, accident-free and environmental friendly.

Disadvantages of Pipelines

• It is not flexible, i.e., it can be used only for a few fixed points.
• Its capacity cannot be increased once it is laid.
• It is difficult to make security arrangements for pipelines.
• Detection of leakage and repair is also difficult.

Crude Oil Pipelines

• Salaya-Mathura Pipeline (SMPL)
• Paradip-Haldia-Barauni Pipeline (PHBPL)
• Mundra-Panipat Pipeline (MPPL)

Petroleum Product Pipelines

Remember locations of Oil Refineries and Major Oil producing centers. Pipeline are the ones that connect these centers.

• Guwahati-Siliguri Pipeline (GSPL)
• Koyali-Ahmedabad Pipeline (KAPL)
• Barauni-Kanpur Pipeline (BKPL)
• Panipat-Delhi Pipeline (PDPL)
• Panipat-Rewari Pipeline (PRPL)
• Chennai – Trichy – Madurai Product Pipeline (CTMPL)
• Chennai-Bangalore Pipeline
• Naharkatia-Nunmati-Barauni Pipeline == first pipeline constructed in India
• Mumbai High-Mumbai-Ankleshwar-Koyali Pipeline.
• Hajira-Bijapur-Jagdishpur (HBJ) Gas Pipeline == world’s largest underground pipeline
• Jamnagar-Loni LPG Pipeline == longest LPG pipeline in the world
• Kochi-Mangalore-Bangalore pipeline
• Vishakhapatnam Secunderabad pipeline
• Mangalore-Chennai pipeline
• Vijayawada-Vishakhapatnam pipeline

Share of Oil in India’s Power Generation

India’s Oil Imports

Primary References: NCERT Geography, Encyclopedia Britannica,  Indian Geography by Kullar [Amazon and Flipkart]