In order to confront the challenges and risks of subsea production systems, a number of advanced approaches are available to operators seeking untapped energy resources.
Responsible for designing, building, installing and maintaining the underwater components needed to produce fossil fuels, subsea operators adopt a number of technologies based on the specific requirements of any given project.
The operation of oil and gas subsea systems is a whole-of-lifecycle commitment, concerning the preparation, monitoring, maintenance and restoration of equipment before, during and after production.
Due to the safety risks associated with underwater operations, works require a combination of autonomous systems for a targeted inspection of and intervention in offshore environments to reduce the requirement for manned marine operations.
As a result, the subsea sector has aimed research and development initiatives towards increasing and developing safe and reliable autonomous solutions.
This has resulted in a shift towards the use of autonomous surface vessels and remotely operated underwater vehicles for subsea missions in offshore oil and gas fields.
Through the application of artificial intelligence (AI), these technologies help assess and act upon any challenge a marine environment may pose. Many benefits have arisen from utilising remote piloting, including health and safety, administration and logistical challenges.
There are times, however, when it is not feasible to use remotely operated underwater vehicles. A case-in-point is pipe-laying, where a chase boat commonly supports the pipe-laying vessel by monitoring pipe touchdown.
In this regard, if a remote approach proves to be too problematic, the chase boat is replaced by an autonomous surface vessel. ROVs are well suited to short, well-defined projects involving the inspection, maintenance and repair of offshore jackets. They also work efficiently in unstructured environments where unexpected obstacles and hazards may be present.
According to Helix Energy Solutions, before starting any subsea activity, an assessment of the condition of the subsea wellhead and its components is required. This includes checking for any signs of corrosion, erosion, fatigue leaks or damage using various tools such as downhole gauges, cameras, sensors and logging devices.
Based on the assessment, the scope, objectives and priorities of the maintenance or intervention work can be determined. The latest techniques for subsea wellhead evaluation include failure prediction methods for risk identification, a retrieval tool for one-step cutting and recovery, diagnostic methods for high voltage components as well as finite element analysis for structural assessment.
Combined, these enhance an understanding of potential failures, an improvement in retrieval processes as well as insulation conditions and structural behaviour.
Executing intervention work requires establishing and maintaining a connection between the surface and the subsea wellhead, controlling the well parameters, performing the required actions on the wellhead components, verifying and testing their functionality and integrity as well as documenting and reporting the results.
Ultimately, well intervention involves equipment maintenance, repair work and enhancing operational performance. It extends well life, boosts productivity and helps tackle any environmental complications.
Recent IT technologies in this field include digital twins – virtual models that optimise well performance, reduce costs and enhance safety. Meanwhile, AI interprets complex data, offering insights and predictions for improved interventions. Robotics, on the other hand, aid in hazardous or challenging tasks such as inspections and repair work.
Another method to restore well production involves a multi-stage process. This includes disconnecting and retrieving equipment from the subsea wellhead and the surface. It also sees the demobilising and transporting of all this back to the shore or base, reopening and stabilising the well flow and pressure, evaluating and optimising well performance and productivity and updating (and maintaining) its records and history.
Ultimately, Helix suggests, any subsea activity is a complex undertaking that requires careful planning and execution. However, by following the appropriate steps, offshore energy proponents should be able to meet their production goals while minimising risks and costs.
