| Written by Mark Buzinkay
Table of contents:
- What are bridge-linked platforms for offshore energy?
- How do bridge-linked platforms organise their tasks?
- Notable existing complexes
- POB Management on bridge-linked platforms
- Electronic POB: 24/7/360 awareness
- FAQ
- Takeaway
- Glossary
What is a bridge-linked platform for offshore energy?
In the early North Sea (1970s–80s), operators discovered that separating functions across several jackets and tying them together with bridges improved safety, uptime, and expandability. Instead of putting drilling, processing, power, and living quarters on a single high-risk structure, fields like Ekofisk, Valhall and Oseberg were developed as multi-installation hubs where bridge-linked platforms shared power, control, and evacuation systems. The Ekofisk Complex grew into a web of bridged installations at ~70 m water depth; by the 2010s the central complex alone comprised nine bridge-connected platforms within a larger 29-platform field system. (1)
Through the 1980s–90s, the approach spread across the UK and Norwegian sectors. Complexes such as Oseberg (A, B, D bridged) and Valhall (drilling, processing/compression, and quarters originally bridged; later additional bridge-connected units) exemplified the pattern: modular expansion with clear functional segregation. (2)
In gas-prone southern North Sea blocks, multi-platform hubs like Leman Alpha and LOGGS emerged; these five-platform bridge-connected complexes gathered and processed gas from satellite wellheads for export to shore. The design allowed brownfield tie-ins over decades. Some of these hubs are now being decommissioned, marking a new phase in the life cycle of bridge-linked platform systems.
From the 2000s onward, the Persian Gulf adopted and scaled the concept into “super-complexes.” Qatar’s Al-Shaheen and Abu Dhabi’s Umm Lulu / Umm Shaif / Al Nasr developments feature multiple bridged topsides (processing, riser, utilities, and large accommodation) at modest water depths (~60–70 m). These clusters centralise processing for dozens of wellhead towers and hundreds of wells. (3)
Industry sources indicate there are thousands of offshore platforms worldwide (with hundreds in the North Sea alone), of which a significant subset are arranged as bridge-linked complexes or hubs. Today, most bridge-linked platforms are concentrated in mature shelf provinces with many fixed jackets: notably the North Sea (UK, Norway, Netherlands) and the Persian Gulf (Qatar, UAE).
How does a bridge-linked platform organise its tasks?
A bridge-linked platform complex is engineered as a distributed plant. Steel bridges (often with pipe racks and cable trays) connect jackets so people, power, hydrocarbons, and control signals can move safely between them, while physical separation reduces incident escalation risk.
Typical roles:
- Production/Processing (PCP/PU/CPP): Receives multiphase fluids, performs separation (oil, gas, water), gas compression, dehydration, and export pumping. Designs can be large: Valhall’s original processing platform was designed for up to ~168,000 bbl/d of oil and 350 MMscf/d of gas. (4)
- Drilling/Wellhead (DP/WP): Provides well slots, derrick, BOP handling, and sometimes water- or gas-injection wells. Splitting drilling from processing allows maintenance or drilling campaigns with less impact on production.
- Compression/Riser/Reception (RP/CRP): Hosts export risers, gas compression, import/export metering, and manifold functions—often the tie-in node to trunk pipelines (e.g., Norpipe from Ekofisk).
- Utilities/Power (UP): Power generation, water treatment, chemical injection, flare, and emergency systems. In super-complexes, dedicated gas-treatment or separation platforms sit alongside utilities via bridges.
- Accommodation/Quarters (QP/LLQ/PUQ): Living quarters, control room, medical, workshops, lifeboats. Crew complements on North Sea hubs typically range into the low hundreds; for example, Bruce’s PUQ can house up to 168, and the historic Valhall quarters housed ~208.
Operationally, the bridges carry pipe racks (oil, gas, produced water, fuel gas, firewater), electrical feeders, instrument air, and fibre-optic controls. Safety philosophy uses segregation: high-risk process equipment sits apart from living quarters; blast/fire zoning and emergency egress routes are planned so that one platform can be abandoned while others remain safe. This modularity also eases brownfield work—adding a new water-injection or compression platform with a short bridge can unlock debottlenecking without a major rebuild. (5)
Modern complexes often integrate with unmanned satellites (normally-unattended wellhead platforms) via subsea lines; the hub handles processing/export while satellites deliver fluids. In gas systems (e.g., Cygnus, Leman), the central bridged hub dehydrates and compresses for export to shore. In liquids-rich systems (e.g., Valhall, Oseberg), the hub stabilises oil for pipeline export and conditions gas for sales or reinjection.
Notable existing complexes
- Ekofisk Complex (Norwegian sector, North Sea) — One of the earliest and most extensive examples of a bridge-linked platform centre. Water depth ~70 m. The wider field has dozens of platforms with multiple bridges in the central hub. Historically, Ekofisk exported oil and gas via the Norpipe system (to Teesside and Emden). Crew numbers vary by era, but the complex supports large resident populations. (6)
- Valhall Field Center (Norwegian sector, North Sea) — Originally three bridged platforms (production, drilling, quarters), later expanded with additional bridge-connected units and flank platforms. Water depth ~70 m. The original processing platform was designed for ~168,000 bbl/d oil and 350 MMscf/d gas; the quarters platform historically accommodated ~208 people. Long-term redevelopment keeps the hub active toward mid-century.
- Oseberg Field Centre (Norwegian sector, North Sea) — Three bridged platforms (A, B, D) at ~100 m water depth, plus satellites (e.g., Oseberg C/H). The hub processes and exports via the Oseberg Transport System to the Sture terminal. Oseberg illustrates phased growth where new bridged units and satellites extended field life. (7)
- Bruce Complex (UK sector, Northern North Sea) — Three bridge-linked platforms: a PUQ (with accommodation up to 168 persons), a drilling platform, and a compression/reception platform ~340 km NE of Aberdeen. Gas/condensate processing and compression are centralised in the hub. (8)
- Leman Alpha (UK Southern North Sea) — A five-platform bridge-connected gas complex (installed from the late 1960s), gathering and processing for export to Bacton. A classic gas-hub configuration with production, drilling, compression, and utilities on separate bridged jackets.
- Cygnus Alpha (UK Southern North Sea) — Three bridge-linked platforms: wellhead/drilling (AWHP), processing/utilities (APU), and living quarters/control (AQU), with a remote Bravo wellhead satellite 7 km away. Gas exports to Bacton. Modern illustration of a compact bridged gas hub. (9)
- Al-Shaheen (Qatar, Persian Gulf) — Qatar’s largest offshore field at ~60 m water depth. The development includes dozens of platforms with bridges in multiple clusters. Field production has reached ~240,000 bbl/d historically; ongoing “Gallaf” phases add new bridged topsides and interconnecting bridges. Crew sizes vary across clusters, with accommodation platforms serving large rotating workforces. (10)
- Umm Lulu / Umm Shaif / Al Nasr Super-Complexes (Abu Dhabi, Persian Gulf) — Umm Lulu includes six bridge-linked platforms (gas treatment, separation, riser, utilities, accommodation, water disposal). The neighbouring Umm Shaif super-complex and the Al Nasr complex (increased to ~65,000 bbl/d in one phase) exemplify the Gulf’s large, shallow-water bridged hubs integrated with Das Island logistics. Typical sea depths are ~60–75 m. (11)
These examples show the range—from legacy North Sea hubs to modern Gulf super-complexes—where the bridge-linked platform concept delivers scalability, safety segregation, and long-term operability across varying water depths and product streams.
POB Management on Bridge-Linked Platforms
Managing Personnel on Board (POB) is a critical task on any offshore installation, but it becomes significantly more complex on a bridge-linked platform. Unlike a single standalone unit, a bridged complex consists of multiple interconnected structures—production, drilling, utilities, accommodation, riser, and compression platforms. Each platform has its own safety zoning, evacuation equipment, and muster stations. As a result, knowing not just how many people are offshore, but exactly where they are located is essential for safety, logistics, and regulatory compliance.
Traditionally, POB management relied on manual systems: paper lists, radio calls, badge swipes, and crew check-ins during helicopter flights or boat transfers. On a bridged hub, this required coordination between several control rooms, often with separate manifests that had to be reconciled. This created risks: discrepancies in headcount, delayed updates, and incomplete location data. In an emergency, operators needed to ensure lifeboat capacity per platform, but if staff moved across bridges during their shift, manual logs could lag behind, creating uncertainty.
Daily operations also depend on an accurate POB. Catering, bed management, work permits, and shift scheduling all require up-to-date information about who is on which platform. On a large complex such as Ekofisk, Valhall, or Umm Lulu, hundreds of workers may rotate across multiple bridges daily—welders moving to the drilling deck, technicians going to the utilities platform, inspectors working on the riser platform. Without a unified, real-time system, control rooms faced difficulties in maintaining situational awareness.
Electronic POB: 24/7/360 Awareness
The introduction of electronic POB (e-POB) systems transformed this challenge. These systems use digital badges, RFID tags, or Real-Time Location Systems (RTLS) to automatically register worker presence and movement across the entire bridge-linked complex (see also: electronic T-card).
Key benefits:
Automatic Tracking Across Platforms
When a worker crosses a bridge, the system updates their location instantly. Control centres see not only the total headcount offshore but also the exact distribution of personnel by platform. This eliminates manual reconciliations and ensures that each structure’s muster list is accurate at any given moment.
24/7/360 Correct POB
Unlike paper-based logs updated at shift changes, electronic POB provides continuous visibility. Even at night or during unscheduled movements, the system reflects real-time positions. In a fire or gas release on a production platform, operators immediately know how many people are there, how many are in safe zones, and whether evacuation routes and lifeboat capacity are sufficient.
Integration with Safety and Emergency Systems
E-POB integrates with access control, mustering stations, and lifeboat boarding points. During a drill or real emergency, mustering data is instantly compared with the electronic register to identify missing persons. If a worker is still on the drilling deck when the alarm sounds, the system highlights their last known location.
Operational Efficiency
Beyond safety, e-POB optimises logistics. Bed management systems automatically release cabins when workers depart. Catering can plan meals based on real headcount. Work permit systems confirm that only authorised personnel are present in designated areas. And think about the different ways how crew and visitors arrive and depart from the platform - via vessels and helicopters (see also: Crew Companion Heliport App)
Regulatory and Audit Assurance
Regulators in regions like the North Sea require strict proof of POB control. Electronic records provide transparent logs of who was onboard, where, and when—supporting audits and incident investigations.
On bridge-linked platforms, traditional POB methods struggle with complexity, especially when personnel move frequently between processing, drilling, and accommodation units. Electronic POB systems solve this by providing continuous, real-time, 24/7/360 situational awareness. They ensure that in both routine operations and emergencies, operators know exactly who is onboard and where they are. For large multi-platform complexes, this technology is no longer a luxury—it is a fundamental enabler of safe, efficient offshore operations.
FAQ: Bridge-Linked Platforms and Electronic POB
What is a bridge-linked platform, and why is it used?
A bridge-linked platform is an offshore installation where multiple platforms—such as drilling, production, utilities, and accommodation units—are connected by steel bridges. This design improves safety by separating hazardous operations from living quarters, allows modular expansion, and enables efficient transfer of people, power, and hydrocarbons across the complex.
How is Personnel on Board (POB) managed on bridge-linked platforms?
POB management ensures operators know exactly how many people are offshore and on which platform. In traditional systems, paper lists and radio updates were used, but these were slow and prone to errors. Today, large complexes rely on electronic POB to maintain accurate, real-time records of crew distribution, essential for safety, logistics, and regulatory compliance.
What advantages does electronic POB (ePOB) provide?
Electronic POB uses badges, RFID, or real-time tracking to automatically update worker locations across bridge-linked platforms. It delivers continuous 24/7/360 visibility, ensuring accurate muster lists during emergencies, verifying lifeboat capacity, and highlighting missing personnel. Beyond safety, ePOB also optimises logistics such as bed assignments, catering, and work permits, while providing transparent audit trails for regulators and operators (see also Crew Companion as a reference solution).
TAKEAWAY
POB management is especially complex on bridge-linked platforms, where crews move between multiple interconnected structures. Traditional paper-based or manual systems often left dangerous gaps in accuracy and response times. Electronic POB systems solve this by delivering 24/7/360 real-time visibility of every worker’s location, ensuring correct muster lists, safe evacuation capacity, and compliance with regulations. By linking access control, mustering, and logistics into a unified digital register, e-POB not only enhances emergency readiness but also streamlines daily operations, from catering to bed management, making it an essential tool for safe and efficient multi-platform offshore operations. (12)
Delve deeper into one of our core topics: Personnel on board
Glossary
Hydrocarbons are organic compounds made up of hydrogen and carbon atoms, forming the basis of crude oil, natural gas, and many derived fuels. They occur naturally in sedimentary rocks, created from the decomposition of ancient plant and animal matter under heat and pressure over millions of years. Hydrocarbons are categorised into alkanes, alkenes, alkynes, and aromatics, each with distinct chemical properties and industrial uses. They remain the foundation of global energy production and petrochemical industries. (12)
References:
(1) https://www.conocophillips.no/what-we-do/greater-ekofisk-area/ekofisk
(2) https://www.norskpetroleum.no/en/facts/field/valhall/
(4) https://en.wikipedia.org/wiki/Valhall_oil_field
(5) https://www.nature.com/articles/s41598-022-11975-2
(6) https://en.wikipedia.org/wiki/Ekofisk_oil_field
(7) https://www.norskpetroleum.no/en/facts/field/oseberg
(8) https://www.serica-energy.com/bruce-area-ICOP
(9) https://www.spirit-energy.com/our-operations/uk/producing-fields/
(11) https://www.offshore-technology.com/projects/umm-lulu-development-abu-dhabi-uae/
(12) Tissot, B. P., & Welte, D. H. (1984). Petroleum Formation and Occurrence (2nd ed.). Springer-Verlag.
Note: This article was partly created with the assistance of artificial intelligence to support drafting. The head image was created with Canva.
