When Contractors Collide: Managing Interfaces to Keep Offshore Oil and Gas Projects on Schedule

For this article, Offshore Engineer interviewed Aghalar Gasimov, Technical Interface & Systems Completion Discipline Lead at QatarEnergy LNG in Doha, Qatar. A Chartered Engineer through the UK's Energy Institute, Gasimov has more than 15 years of experience in offshore EPC, brownfield construction, pipeline projects, megaproject interface management and systems completion. His current work on QatarEnergy LNG's North Field Production Sustainability program involves contractor coordination, interface governance, project risk management and systems completion.

The importance of managing these interfaces becomes particularly apparent when progress within one contractor's scope does not translate into readiness for the next stage of execution.

"A fabrication contractor can report good progress while the installation team is still waiting for an agreed handover date. A brownfield work pack can be complete while access to the operating facility remains unresolved. In offshore engineering, procurement and construction (EPC), these gaps can put a shutdown window, vessel campaign or first-production milestone at risk," Gasimov said.

Managing these risks requires more than monitoring contractor progress. Every critical dependency must have a party accountable for delivering it, another authorized to accept it and a deadline aligned with the next stage of execution. An interface register covering critical boundaries, agreements and obligations is valuable only when it helps drive those decisions before delays materialize.

The UK Oil and Gas Authority's review of projects undertaken between 2011 and 2016 placed ultimate responsibility for interface management with the project management team (PMT).¹

That responsibility becomes particularly important where engineering, fabrication, installation and operations are divided among multiple contractors.

The challenge is not simply to identify where responsibilities meet, but to ensure that work can continue across those boundaries without interruption.

Set the Boundaries Before Offshore Execution Begins

Many of the problems that eventually emerge during offshore construction originate much earlier, when contractual boundaries and execution responsibilities are first established.

"Interface planning should begin during front-end engineering design (FEED) and tender preparation. The Construction Industry Institute's (CII) research recommends starting during concept development; research across seven subsea developments also supports early contractor involvement and clearer scope definition. By award, each package needs an agreed boundary, including exclusions, inputs from other parties and obligations at handover," Gasimov explained.^{2 3}

A responsibility matrix provides the foundation, but it is the interface agreements that establish how those responsibilities translate into execution. Each agreement should identify the deliverable, the issuing and receiving parties, acceptance criteria, required delivery date and escalation route.

A designated point of contact can coordinate communication, but accountability for delivery must remain with the relevant package managers. Where an issue crosses contractual boundaries, the operator's PMT must have the authority to resolve it.

The importance of this approach is illustrated by the Coral Sul floating liquefied natural gas (FLNG) development offshore Mozambique.

Technip Energies describes how six operating centers worked through shared information and an interface management system to coordinate the project's execution. Construction, transportation, installation and start-up requirements were considered early enough to be incorporated into the work.

According to the company's project case study, the facility achieved sail-away readiness in line with the contractual schedule, without offshore carryover.⁴

The experience illustrates a fundamental requirement in offshore EPC execution: the needs of the next contractor or execution phase must be established while the preceding package still has the opportunity to accommodate them.

When a Late Handover Threatens an Offshore Campaign

Few interface problems become more costly than those discovered when an offshore installation campaign is approaching.

A vessel may have been committed, fabrication may be nearing completion and offshore personnel may already be preparing for mobilization. Yet the entire sequence can still depend on an unresolved approval, incomplete documentation or an unconfirmed handover.

This is why interface management cannot operate separately from project scheduling.

Contractors need to work from a common schedule basis, with clear links between their activities and the deliverables required from other parties. An interface deadline should reflect when the receiving contractor actually needs the information, equipment or completed work, including sufficient time for review, corrections and formal acceptance.

Connecting interface records to the integrated master schedule allows the PMT to identify the activities and milestones that could be affected by delays.

A Project Management Institute (PMI) paper examining interface management in oil and gas projects similarly describes linking interface requests with affected activities, costs and changes.⁵

The importance of understanding these dependencies becomes particularly clear when offshore vessels are involved.

"Consider a planned offshore installation campaign. The vessel commitment depends on fabrication release, transport readiness and receiving-site access. If an unresolved interface threatens one prerequisite, the PMT should assess the affected sequence and recovery options immediately. A reply delivered within an administrative response period may still arrive too late for the campaign," Gasimov said.

For every priority interface, the required acceptance date should be compared with the latest forecast acceptance date. A widening gap provides an early warning that intervention may be needed.

That difference should not, however, be confused with critical-path float. Project planners must assess the downstream schedule logic, available mitigation measures and actual exposure to key milestones.

Where uncertainties are significant, critical interface dependencies should also be included in schedule risk analysis rather than assuming that each contractor will deliver against its earliest forecast.

The importance of managing separate packages against a common production target was demonstrated during the development of Johan Sverdrup offshore Norway.

Equinor attributed preparations for the field's accelerated start-up schedule to close collaboration with partners and suppliers from the beginning of the project. During the final readiness phase, the connected platforms were treated as one installation.

For offshore project teams, the lesson is clear: progress within individual contracts matters only if the combined work supports the wider installation, commissioning and production schedule.

Weekly interface reviews should consequently focus on the next major execution windows, identifying the deliverables that could affect the critical path, consume remaining schedule float or require management intervention before a vessel campaign or shutdown commitment is exposed.

Resolve Interface Disputes Before They Reach the Platform

Identifying a problem is only the first step. Preventing it from affecting offshore execution depends on how quickly the responsible parties can reach an agreement and implement a workable solution.

"An interface meeting should end with a decision, an owner and an achievable date. When agreement cannot be made, escalation needs a concise statement of the dependency, the affected milestone and the available options. Package managers should bring the right decision-makers together before the issue becomes a request for acceleration offshore," Gasimov said.

The objective is to resolve disputes while recovery remains possible, rather than allowing them to create additional work or disruption during offshore installation.

Experience gained on offshore EPC projects in the Middle East, including Gasimov's current assignment, demonstrates how a structured interface agreement process can help maintain control across contractor boundaries.

The process begins by defining each new interface, identifying the parties involved and entering the issue into the interface register.

The requirements, responsibilities and required dates are then discussed with the interfacing party before the contractor prepares the formal interface agreement (IA).

As illustrated in Figure 2, the agreement proceeds through company review and endorsement, followed by third-party sign-off. Where agreement cannot be reached, outstanding issues are returned for further discussion and revision.

Once endorsed and signed, the IA is formally issued to both parties. Its obligations remain subject to monitoring until the agreed work has been completed and accepted.

Effective reporting is equally important.

Contractors must be encouraged to identify emerging constraints while sufficient time remains to address them. Forecast dates should be challenged where necessary, and incomplete evidence should not be accepted simply to demonstrate progress.

At the same time, early disclosure must lead to meaningful action: acknowledging the problem, assigning responsibility for a decision and ensuring that the agreed response is implemented.

The same discipline applies when an interface resolution changes the original execution requirements.

If resolving an issue affects scope, cost, contractual obligations or the approved project schedule, the matter must proceed through the relevant change-control process.

Consequences for all affected packages should be assessed before authorization. An interface agreement establishes coordination between parties, but it does not independently authorize additional work or replace a contractual variation.

Both the original commitment and any approved revision must remain traceable.

From Fabrication Yard to Offshore Start-Up: Making Handover Count

For major offshore oil and gas developments, the transition between fabrication, installation, commissioning and operations represents one of the most important tests of interface management.

A facility may be declared ready for sail-away, but that status has limited value if essential documentation is incomplete, commissioning requirements remain unresolved or the receiving team lacks the resources to continue the work.

"Offshore readiness should be checked against the work that can actually proceed. Before mobilization or sail-away, confirm the agreed completion status, documentation, access, resources and disposition of outstanding work. Carryover needs an accountable owner, an executable offshore plan and acceptance by the receiving organization. Reclassifying unfinished work does not remove its schedule impact," Gasimov explained.

These checks are essential to ensuring that the receiving organization can continue execution without inheriting unresolved constraints that may be more difficult and costly to address offshore.

Brazil's P-78 floating production, storage and offloading (FPSO) vessel provides an example of how integration between execution phases can support offshore delivery.

Petrobras reported that commissioning and operations personnel worked aboard the vessel during its transfer from Singapore to Brazil. This allowed commissioning activities to progress during the voyage and eliminated the need for a stop in sheltered Brazilian waters. ⁷

A similar emphasis on early involvement of the receiving organization can be found in BP's experience at the Shah Deniz development in Azerbaijan.

In an account published by the International Association of Oil & Gas Producers (IOGP), BP described how operations and commissioning personnel worked together from the beginning to strengthen handovers and start-up preparation.⁸

Both examples reinforce the importance of involving commissioning and operations teams well before formal handover, when adjustments to construction, completion and execution plans can still be made.

Brownfield Work: Protecting the Shutdown Window

The risks become particularly significant when new offshore infrastructure must be integrated with existing oil and gas production facilities.

Brownfield integration requires particular attention to operating assets, access restrictions, shutdown availability and simultaneous operations (SIMOPS).

Construction progress alone cannot determine readiness for a tie-in. The work must also align with operational constraints and the agreed execution window.

"For brownfield work, operations must also help establish shutdown availability, access restrictions and simultaneous operations (SIMOPS) arrangements. QatarEnergy LNG's public description of its North Field Production Sustainability program combines new offshore facilities with substantial brownfield connections. That provides another setting where progress across separate packages must converge on an agreed execution window," Gasimov noted.⁹

Such developments require progress across separate engineering, construction and installation packages to be closely coordinated with operational requirements.

Where one package is delayed, the consequences may extend to work already planned by other contractors, as well as to the operating facility that must accommodate the connection.

The PMT must therefore ensure that contractor forecasts, operational readiness and shutdown commitments are assessed together rather than in isolation.

Closing an Interface Is Not the Same as Completing the Work

As offshore projects move towards commissioning and first production, pressure to close outstanding interface records can intensify.

But an answered query does not necessarily mean that the underlying dependency has been resolved.

"Closure should follow accepted evidence and confirmation that affected plans have been updated. Where an interface decision leaves execution actions outstanding, track those actions separately to completion. Counting answered queries alone can conceal work that remains blocked," Gasimov said.

This distinction is essential. A project can report an increasing number of closed interface records while contractors still face unresolved obstacles that prevent work from proceeding.

The most useful question in an offshore EPC interface review is therefore straightforward: Can the next contractor proceed on the agreed basis and on the agreed date?

Answering that question requires realistic forecasts, clearly assigned authority, timely decisions and active participation from the receiving organization.

For offshore oil and gas operators and contractors, effective interface management is ultimately about protecting execution. Resolving contractual and technical boundaries before they interfere with fabrication, vessel campaigns, offshore installation or start-up gives project teams the opportunity to prevent avoidable delays, rather than dealing with their consequences offshore.