Offshore oil and gas production

Published on 02.25.2015

5 min read

Middle School High School

STEM Technology

1. The Global Surge in Offshore Production

Offshore oil and gas production continues to grow: in 2024, it accounted for 30% of global oil production and 32% of global gas production. In this sector, so-called “ultra-deepwater” operations (beyond 1,500 meters of water depth) are becoming increasingly significant. Beyond 400 meters, fixed platforms resting on the seabed are replaced by semisubmersible platforms or large floating production units. Shown here is the platform of the Laggan field, near the Shetland Islands.

2. North Sea Platforms

The first platforms were installed in shallow waters (less than 400 meters). They are supported by steel legs or concrete gravity-based structures resting on the seabed. The North Sea contains more than 450 installations of this type, usually made up of a main production platform, living quarters connected by a walkway, and a helicopter landing pad.

3. Constant Monitoring

The control room of the Grondin platform, located offshore from Port-Gentil in Gabon. From this single point, operators can manage all operations, monitor measurement instruments, and transmit voice messages—including alerts—to the various teams at work.

4. Personnel Transport

Personnel transfers are carried out by helicopter and by boat. Wearing a dry suit equipped with life jackets is mandatory to ensure survival at sea in the event of an accident while waiting for rescue. Baggage checks are very strict: no dangerous objects, no alcohol, no lighters. Smoking is prohibited on offshore platforms.

5. Night Work

Work in the oil and gas extraction industry never stops.
On an offshore platform — as seen here in the photo of the Paragon L1115 off the coast of Qatar — operations run continuously, 24 hours a day. Two teams, one working during the day and the other at night, rotate without interruption to ensure safety, constant monitoring and ongoing production.
Personnel generally work for several consecutive weeks in rotation (for example, two weeks offshore), followed by rest periods of at least equal length, usually , in accordance with industry practices.

6. Living Areas Outside Working Hours

The living quarters include the bedrooms — usually with 2 or 3 bunks, sometimes single rooms — as well as the restaurant, rest areas and sports rooms. Here, the television room on the L7CC platform in the North Sea, off the coast of the Netherlands. A medical room is also available to provide first aid in case of an accident.

7. Safety Requirements

Safety is a constant concern on offshore platforms. A dedicated engine powers the pumps that would be used in the event of a fire. The oil industry still remembers the tragic Piper Alpha accident on July 6, 1988, which caused 167 deaths off the coast of Scotland, as well as the Deepwater Horizon rig disaster on April 20, 2010, in the Gulf of Mexico (11 deaths). Shown here: two electricians on board the Grondin platform, offshore from Port-Gentil (Gabon).

8. Semi-Submersible Platforms

When the water depth exceeds 400 meters, floating platforms are used. These structures are equipped with ballasts and anchored to the seabed to keep them stable and prevent drifting. Shown here is the West Phoenix platform operating in the Laggan gas field, 125 km west of the Shetland Islands and connected to the Tormore field. Drilling is carried out in 600 meters of water, and the wells extend through sedimentary layers down to 3,000 meters. Subsea pipelines transport the production to shore.

9. Drilling Ships

Deepwater subsea drilling is carried out by specialized dynamically positioned vessels known as drillships. Renting a drilling ship in Europe costs around one million euros per day. Shown here is the West Gemini during operations off the coast of Angola.

10. Like a Giant Motionless Ocean Liner

The development of deepwater or ultra-remote offshore fields is carried out using massive floating units known as . These vessels produce, store, and offload hydrocarbons directly onto tankers. The Pazflor FPSO, anchored off the coast of Angola, is connected to 49 subsea wells spread over 600 km² (six times the size of Paris) in water depths ranging from 600 to 1,200 meters.

11. A Real Factory Beneath the Sea

Development diagram of the Akpo deepwater offshore field, off the coast of Nigeria. Twenty flexible risers bring hydrocarbons up to the surface, while twenty-two others inject the water and gas used to push them toward the production well. Increasingly, technical operations are carried out directly on the seabed, which requires installing and managing numerous pieces of equipment. The Akpo field produces and gas.

12. Offshore Fields Have Long Lifespans

The Anguille field, off the coast of Gabon, is an example of the redevelopment of a mature field that has been producing for 60 years. From a new platform, 21 additional wells will be drilled in 30 meters of water. The platform is unmanned and operated remotely.
In this new project, flare gas volumes have been reduced by 90%. Oil companies have committed to eliminating or reducing the use of flares, which are used to burn off the gas associated with oil production.