| Smash 2025 Basic test 04 Q20. Discuss the location of various petroleum crude resources in India and the world. What are some steps taken by the government to make India self-sufficient in supply of petroleum crude. Have they been successful? |
| PYQ Q. It is said the India has substantial reserves of shale oil and gas, which can feed the needs of country for quarter century. However, tapping of the resources doesn’t appear to be high on the agenda. Discuss critically the availability and issues involved. (2013) Q. What are the economic significances of discovery of oil in Arctic Sea and its possible environmental consequences? (2015) |
Petroleum reserves are found in sedimentary basins, where organic matter is trapped under pressure. Offshore reserves, discovered since the mid-20th century, now account for ~30% of global crude oil production. Their distribution is linked to continental shelf geology, passive margins, and deep-water basins.
Major Offshore Oil Regions
Major Offshore Oil Regions of the World
- North America – Gulf of Mexico (USA, Mexico), Alaska’s Beaufort & Chukchi Seas.
- South America – Brazil’s Campos & Santos Basins (pre-salt), Guyana-Suriname Basin.
- Europe – North Sea (UK, Norway, Denmark), Barents Sea (Arctic).
- Africa – West Africa (Nigeria, Angola, Ghana), East Africa (Mozambique, Tanzania gas fields).
- Middle East – Persian Gulf (Saudi Arabia’s Safaniya, Qatar, UAE, Iran, Kuwait).
- Asia – South China Sea, Bay of Bengal (KG-D6 India, Bangladesh, Myanmar), Sakhalin (Russia).
- Australia – North-West Shelf (Western Australia).
Difference between Offshore Reserves and Onshore Reserves
| Aspect | Onshore Reserves | Offshore Reserves |
| Location | Found in continental interiors and basins (eg– Middle East deserts, Siberia, Texas). | Found in continental shelf, slope, and deep-sea basins (eg– Gulf of Mexico, North Sea). |
| Geological Setting | Rift basins, foreland basins, older sedimentary rocks. | Marine sedimentation, deltaic deposits, pre-salt basins (Brazil, West Africa). |
| Exploration & Technology | Easier access, drilling by rigs on land. | Complex technology (floating rigs, subsea pipelines, deep-water drilling). |
| Cost of Extraction | Relatively cheaper (low capital investment). | Highly capital-intensive, requires international oil companies. |
| Environmental Risks | Land degradation, groundwater pollution. | Oil spills, marine ecosystem damage (eg– Deepwater Horizon 2010 in Gulf of Mexico). |
| Geopolitics | Mostly within national boundaries. | Often disputed maritime zones (eg– South China Sea). |
| Reserves | Historically dominant (eg– Middle East onshore super-giants like Ghawar, Saudi Arabia). | Increasing share, especially deep-water basins (Brazil, West Africa). |
While onshore reserves dominate historically, offshore reserves are growing in importance, representing the future frontier of global petroleum geography.
