Petroleum Energy

Petroleum and liquid hydrocarbons are critical drivers of India’s economic growth, constituting the second-largest component of its commercial energy consumption after coal. India relies heavily on crude oil imports to meet over 85% of its domestic refinery demand. The country’s petroleum reserves are geologically tied to marine sedimentary basins, localized within the continental shelves, coastal plains, and structural grabens of the Peninsular flanks.

1. Geological Distribution and Sedimentary Basins

The Directorate General of Hydrocarbons (DGH) classifies India’s 26 sedimentary basins into four distinct categories based on their proven commercial maturity and hydrocarbon potential.

Category I Basins (Proven Commercial Productivity)

These basins possess established commercial production infrastructure.

• Cambay Basin: Located in Gujarat; a highly productive intracratonic rift basin.
• Assam Shelf: Part of the Assam-Arakan fold belt; India’s oldest hydrocarbon province.
• Mumbai Offshore Basin: A massive carbonate platform basin on the western continental shelf.
• Krishna-Godavari (KG) Basin: A prolific deltaic deep-water basin on the eastern coast.
• Cauvery Basin: Extends across coastal Tamil Nadu and its offshore shelf.
• Rajasthan Basin: Centered around the Barmer graben; a major onshore producer.

Category II, III, and IV Basins

These range from basins with known hydrocarbon accumulations that are not yet commercially viable (Category II, e.g., Kutch, Mahanadi) to those with unproven prospects (Category III, e.g., Himalayan Foothills) and completely unexplored areas (Category IV, e.g., Vindhyan, Pranhita-Godavari).

2. Major Petroleum Producing Regions

India’s petroleum production is divided into two primary geographic sectors: Onshore (land-based) and Offshore (sea-based) fields.

Western Offshore Region

This is India’s most productive petroleum zone, contributing the largest share of domestic crude oil.

• Mumbai High: Discovered in 1974 by the Oil and Natural Gas Corporation (ONGC) using the jack-up drilling rig Sagar Samrat. It lies 176 km off the Mumbai coast and features a limestone reservoir.
• Bassein (Vasai) Field: Located south of Mumbai High, this field contains massive reserves of natural gas and oil.
• Aliabet Island: Situated in the Gulf of Khambhat near Bhavnagar; holds significant shallow-water reserves.

The Western Onshore Region (Gujarat and Rajasthan)

• Gujarat Plains: The Cambay Basin houses major fields such as Ankleshwar (historically called the ‘Fountain of Prosperity’), Kalol, Nawagam, Mehsana, and Sanand.
• Barmer Basin (Rajasthan): One of India’s most significant onshore discoveries. The Mangala field, commissioned in 2009, is the largest onshore crude oil discovery in India in decades. Other adjacent active fields include Bhagyam and Aishwarya (together known as the MBA fields).

The Northeastern Region (Assam Valley)

This is the pioneer oil-producing region of India, stretching along the Brahmaputra and Surma valleys.

• Digboi: The oldest operating oil field and refinery in India, where commercial oil production first began in 1889.
• Naharkatiya and Moran-Hugrijan: Developed later along the southern banks of the Brahmaputra River to supply crude to the Noonmati (Guwahati) and Barauni (Bihar) refineries.

Eastern Offshore Region

• Krishna-Godavari & Cauvery Deltas: Primarily recognized for deep-water natural gas, though substantial oil discoveries exist in the offshore blocks (such as the D6 block in the KG Basin).

3. Downstream Infrastructure: Oil Refineries

India has established itself as a major global refining hub, possessing a total refining capacity that exceeds its domestic consumption. This surplus makes refined petroleum products one of the country’s top export commodities.

Public Sector Refineries (PSUs)

• Digboi (Assam): Managed by Indian Oil Corporation Limited (IOCL); the oldest operational refinery.
• Koyali (Gujarat), Mathura (Uttar Pradesh), Panipat (Haryana), and Barauni (Bihar): Major market-based or pipeline-linked inland refineries managed by IOCL.
• Visakhapatnam (Andhra Pradesh) & Kochi (Kerala): Coastal refineries optimized for direct crude import processing, managed by HPCL and BPCL respectively.

Private and Joint Venture Refineries

• Jamnagar (Gujarat): Owned by Reliance Industries Limited, this is the world’s largest grassroots refinery complex, featuring a high complexity index capable of processing heavy, sour crude.
• Vadinar (Gujarat): Operated by Nayara Energy (formerly Essar Oil), another massive private coastal refining unit.
• Bina (Madhya Pradesh) & Guru Gobind Singh Refinery (Bathinda, Punjab): Major joint-venture inland refining complexes.

4. Regulatory Frameworks and Reforms

The Indian oil and gas exploration sector has undergone structural policy overhauls to attract private and foreign direct investment.

NELP vs. HELP

• New Exploration Licensing Policy (NELP): Introduced in 1997, it utilized a profit-sharing model where private operators bid for blocks and shared profits with the government after recovering their exploration costs. This model often led to disputes over cost audits.
• Hydrocarbon Exploration and Licensing Policy (HELP): Launched in 2016 to replace NELP. It introduced a Revenue-Sharing Model, where operators share a percentage of gross revenue with the government from day one, eliminating cost-recovery disputes.

Key Pillars of HELP

• Uniform Licensing System: A single license for all forms of hydrocarbons, including conventional oil and gas, Coal Bed Methane (CBM), shale gas, and gas hydrates.
• Open Acreage Licensing Policy (OALP): Companies can examine National Data Repository (NDR) data and carve out desired exploration blocks continuously without waiting for formal government tender rounds.

Key Facts for Prelims

• Strategic Petroleum Reserves (SPR): To safeguard against global supply chain disruptions, India has constructed underground unlined rock caverns to store 5.33 Million Metric Tonnes (MMT) of crude oil. These reserves are managed by Indian Strategic Petroleum Reserves Limited (ISPRL) at three locations: Visakhapatnam (Andhra Pradesh), Mangaluru (Karnataka), and Padur (Karnataka).
• PM Ji-VAN Yojana: A financial support mechanism aimed at creating an ecosystem for commercial 2G (Second Generation) ethanol projects, promoting ethanol blending with petrol to reduce crude imports.
• Ethanol Blending Program (EBP): India aims to achieve a 20% ethanol blending target in petrol across the country, utilizing agricultural surplus like sugarcane and damaged food grains to reduce its oil import bill.
• Sagar Samrat Conversion: The iconic Sagar Samrat jack-up drilling rig, which discovered Mumbai High, was successfully converted into a Mobile Offshore Production Unit (MOPU) to handle deep-sea oil extraction.