Mumbai High

Location and Discovery

The Mumbai High Field, formerly known as the Bombay High Field, is an offshore oilfield located approximately 160-176 km west of the Mumbai coast in the Arabian Sea, India. It is situated in the Gulf of Cambay region at a water depth of about 75 meters (246 feet).

The field was discovered in 1974 by an Indo-Soviet oil exploration team using the seismic exploration vessel Academic Arkhangelsky. The discovery was a result of mapping and surveys conducted between 1964 and 1972.

Geology

The Mumbai High Field is a carbonate reservoir, with the main producing zone, L-III, consisting of sedimentary cycles of lagoonal, algal mound, foraminiferal mound, and coastal marsh deposits, capped by a post-middle Miocene shale. The field is structured as a "north-northwest to south-southeast trending doubly plunging Anticline with a faulted east limb," measuring 65 km long and 23 km wide. It is divided into three blocks separated by east-west trending faults, each with different gas-oil contacts, and the reservoirs are approximately 1,355 meters (4,446 feet) deep.

Production History

• Initial Production: The field commenced production on May 21, 1976, initially producing 3,500 barrels of oil per day, which quickly increased to 80,000 barrels per day within three years.
• Peak Production: The field reached its peak production rate of 400,000 barrels of oil per day (bopd) in 1985, maintaining this rate until 1989.
• Current Production: As of 2024, the field produces approximately 134,000 barrels per day (21,300 m³/d).
• Cumulative Production: Over the past 50 years, Mumbai High has produced 527 million barrels of oil and 221 billion cubic meters of gas, accounting for around 70% of India's domestic oil and gas production.

Redevelopment and Expansion

To maintain and enhance production, ONGC has implemented several redevelopment phases:

• Phase One: Started in 2000 and completed in December 2006, this phase involved drilling 73 new wells and 10 sidetrack wells, aiming to add 23.25 million tonnes of crude oil and 6.1 billion cubic meters of gas by 2030.
• Phase Two: Approved in January 2009, this phase aimed to add 17.354 million tonnes of crude oil and 2.987 billion cubic meters of gas by March 2030 through drilling 73 new wells and side-tracking 38 poor producers.
• Phase Three: Approved in June 2014, this phase involved the installation of five wellhead platforms, modifications at 13 platforms, and the drilling of 52 new wells and 24 side-track wells. It was completed in 2017.
• Phase Four: Involves the drilling of 43 wells, completed in December 2022, and the installation of a new offshore platform, completed in February 2023. For Mumbai High South, phase four includes upgrading the ageing water injection facility and installing a new water injection platform (NWIS-R), which was completed in May 2021.

Reserves and Future Prospects

• Remaining Reserves: As of 2020, the field still has a balance reserve of 80 million tonnes (610 million barrels) of oil and over 40 billion cubic meters of gas.
• Production Forecast: Based on economic assumptions, production is expected to continue until the field reaches its economic limit in 2042, with the field currently accounting for approximately 27% of India’s daily oil output.

Infrastructure and Operations

• Pipelines and Facilities: The field is connected by several pipelines, including a sub-sea pipeline laid in 1978 to transport oil to refineries in Mumbai. ONGC has also approved the construction of several pipelines and associated top-side facilities to optimize production.
• Operational Challenges: The field has faced challenges, including a major fire on July 27, 2005, which destroyed a production platform and resulted in significant losses. Operations were also temporarily suspended in 2020 due to COVID-19 cases among employees.

Quality of Crude Oil

The crude oil produced from Mumbai High is of very good quality, with more than 60% paraffinic content, which is significantly higher than the paraffinic content of light Arabian crude (25%).

Ownership and Management

The Mumbai High Field is owned and operated by the Oil and Natural Gas Corporation (ONGC), India's largest crude oil and natural gas company. ONGC is responsible for the exploration, production, and redevelopment of the field.

Contractors and Partners

Several contractors are involved in the development and maintenance of the Mumbai High Field, including Larsen & Toubro as the main EPC contractor and Shelf Drilling among others.

Economic and National Significance

The Mumbai High Field has been crucial for India's energy security, accounting for a significant portion of the country's domestic oil and gas production. It has played a pivotal role in the Indian economy since its discovery and continues to be a major contributor to India's energy needs.