The Problem
Evaluating and Addressing Risks of a Freespan Subsea Pipeline
Subsea pipelines are essential infrastructure for transporting critical resources in the oil and gas industry, but they are highly susceptible to environmental and structural risks. A freespan section of a 3.5-inch MEG pipeline nearshore at a coastal site presented a specific set of challenges requiring immediate attention.
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Structural Risks
Freespan pipelines are unsupported sections of a pipeline where the seabed beneath has eroded or shifted, leaving the pipe exposed and vulnerable to stresses caused by hydrodynamic forces, such as currents and waves. These forces can lead to increased fatigue, deformation, or even rupture of the pipeline, posing a significant threat to its structural integrity. -
Environmental Concerns
Any failure in the pipeline could result in a leak, introducing harmful substances into the marine environment. Such an incident would not only harm marine life but could also lead to reputational damage and legal penalties for the operator. -
Operational Disruptions
Pipeline damage or failure can disrupt the transport of critical resources, leading to downtime, production losses, and increased costs associated with emergency repairs. Moreover, unaddressed freespan sections can exacerbate these risks over time. -
Regulatory Compliance
Industry regulations require operators to routinely inspect and monitor their subsea assets, particularly in areas of known vulnerability like freespan sections. The ability to demonstrate proactive maintenance and remediation is essential for adhering to safety and environmental standards. -
Seabed Hazards and Unknowns
The surrounding seabed may contain debris, trawling scars, or other obstructions that could further compromise the stability of the pipeline or interfere with planned remediation efforts. Understanding these factors is critical to ensuring a safe and effective resolution. -
Data Limitations and Accuracy Needs
The pipeline operator required high-precision data to understand the freespan’s dimensions, the pipeline’s condition, and its interaction with the seabed. Without accurate measurements and a detailed environmental assessment, developing a targeted and effective remediation strategy would be challenging.
This freespan pipeline required a thorough inspection to address these concerns, mitigate risks, and provide the client with actionable insights to safeguard the pipeline’s structural integrity, minimize environmental impact, and maintain regulatory compliance.
Our Solution
A Comprehensive and Precision-Driven Clearance Operation
To address the challenges posed by the freespan pipeline, Atlantas Marine deployed a VideoRay Mission Specialist Defender ROV equipped with advanced imaging and navigation technologies. The operation encompassed several critical tasks:
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Visual Inspection
Using the ROV’s high-definition camera, a detailed survey of the freespan pipeline was conducted. The inspection revealed no signs of damage, deformation, or leakage along the pipeline. Marine growth was observed, with hard growth covering 75-100% and soft growth at 25-50% of the pipeline’s surface within the freespan. The ROV’s internal navigation system ensured precise tracking throughout the inspection. -
Freespan Measurements
Multibeam SONAR technology was employed to measure the freespan. The pipeline’s unsupported section was found to span 28.14 meters, with heights ranging from 0.5x to 1.5x the diameter of the pipeline. These measurements provided critical data for assessing the structural risks associated with the freespan. -
Burial Locations and Touchdown Points
The ROV was used to map the pipeline’s burial locations and touchdown points accurately. These points were recorded using GPS and internal navigation systems, enabling clear identification of transitions between buried and exposed pipeline sections. -
Seabed Survey
In addition to pipeline inspection, a 40m x 30m seabed survey was conducted to evaluate environmental risks and identify any debris or trawling activity near the pipeline. The survey confirmed that the surrounding seabed was free of debris and showed no evidence of trawler damage.
