Why Seawater Injection Commissioning is Different
Grant Gibson, PhD | GATE Energy Founder & Chairman
Seawater Injection or Waterflood Commissioning is not your typical oilfield commissioning.
While oil production process follow well-established separation and processing techniques that many operators are familiar with, waterflood systems introduce novel equipment, unfamiliar chemistry, and strict water quality requirements—making their commissioning uniquely challenging.
After commissioning almost every conceivable piece of waterflood equipment in deepwater, here are five key challenges that we will discuss:
System Complexity & Design
Unfamiliar Equipment
Commissioning = Ruining the Plant
Complex Control Systems & Strict Water Quality
Organizational Challenges
System Complexity & Design
Involves diverse components: source pumps, filtration units, de-oxygenation systems (e.g., Minox, vacuum tower, stripping, oxygen scavenger), sulphate reduction units (SRU), LoSal, and serial #1 high-pressure injection pumps.
Poor commissioning can lead to mechanical failure, water hammer, or biological contamination. In subsea systems, long flowlines can exacerbate issues—poor topsides chemical control can result in corrosion products and “snow” from biological growth at the wellhead.
Water is incompressible, making water hammer a critical issue. Valve tuning and pump startups must account for this, as design oversights can be unforgiving.
Seawater weight and fully water-packed systems can create unexpected vacuum conditions, such as in overboard drain headers—requiring properly placed vacuum breakers. This can also include systems draining down through overboards or backflowing through vessels.
High-point vents must be accessible to bleed air out of the system. Without this, flowmeters may not work properly until sufficient flow sweeps the air out.
Isolations – as the utility systems can be added after production starts, future isolations for tie-ins need to be designed in to avoid a shutdown (ex. connect instrument air)
Project Risk Management – While source pumps and filtration equipment are relatively straightforward, high-pressure injection pumps often pose significant startup risks. To mitigate this, consider designing bypasses to enable early pump testing before integrating the full system.
Unfamiliar Equipment
Many components are not standard for oil & gas technicians, requiring specialized knowledge for commissioning.
Systems like Minox and SRU are rare, and turbine-driven injection pumps involve first-of-kind designs and extremely high pressures.
Parallel pump operation and pressure/flow control must be tested thoroughly—bugs in these systems can be difficult to resolve once operational.
Commissioning = Running the Plant
Unlike hydrocarbon systems, where commissioning focuses on equipment function checks, waterflood commissioning means fully operating the system before handing it over to operations.
The system must run under real conditions to verify water quality, system tuning, and long-term stability.
Complex Control Systems & Strict Water Quality
Integration of serial sub-systems into a seamless, automated process is challenging—these systems are difficult to start up and prone to shutting themselves down if not properly tuned.
Maintaining chemical treatment levels is critical to prevent bacteria growth and membrane fouling. Hypochlorite, oxygen scavengers, biocides, and, in some cases, nitrate injection all interact, requiring a commissioning team that understands both process operations and chemistry.
Organizational Challenges
Waterflood systems are often brought online after hydrocarbon startup, meaning they are not a priority offshore. This leads to limited personnel availability (POB), competing shutdown schedules, and dependency on existing facility utilities.
If the waterflood system is part of the initial project, a dedicated waterflood commissioning team is highly recommended to ensure smooth execution.
Key Takeaway
Waterflood commissioning isn’t just testing—it’s running the system to prove stability before operations take over. Success requires experienced engineers who understand the equipment, process, chemistry, and project risk management.
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