Understanding Risk in Flow Assurance Management
The role of flow assurance in offshore operations involves communicating with asset teams to assess constantly changing conditions. In reviewing, updating, and applying strategies to a system, a manager of flow assurance engineers at BP said that companies should know the biggest risk those systems face and establish clear procedures that can be easily understood by on-site personnel.
At a presentation hosted by the SPE Flow Assurance Technical Section, Oris Hernandez spoke about the strategic initiatives and lessons learned from the formation of BP’s flow assurance team for its US Gulf of Mexico (GoM) operations in 2012. Hernandez is a Western Hemisphere flow assurance at BP.
Hernandez described flow assurance management as an interfacing challenge, with engineers monitoring fields and facility designs to know where to adapt in the midst of continually changing conditions. She said that because maximum production is the goal with any project, minimizing risk is paramount. BP implemented a risk management cycle to identify flow assurance risks, the conditions needed for the risk to materialize, and the processes the company needed to have in place to prevent those risks from happening.
Modeling flow assurance risk requires a thorough understanding of the key stakeholders in an organization and their level of “threat ownership,” a term Hernandez used to describe the responsibilities ascribed to various individuals and subgroups for handling risk.
“Understanding the organization is key,” she said. “I had one flow assurance engineer for each of our assets in the Gulf of Mexico. There is no way that one person alone can manage the risk entirely, so you depend on a lot of people, a lot of interfaces in order to make our hydrate strategies work. We needed to establish who was doing what.”
Upon forming the flow assurance team, BP identified hydrate buildup in its pipelines and flowlines as the biggest immediate risk to its GoM operations, and so it developed a bowtie model to help ascertain the specific threats that could lead to hydrate formation. The model sorted prevention and remediation methods in a pipeline or flowline system as a set of independent and fully functional barriers that, by themselves, should completely stop a risk scenario from developing.
The BP team wanted to account for the multiple processes that could lead to a hydrate blockage in its model. In steady-state conditions, the best preventative measures may be the injection of a low-dosage hydrate inhibitor. Hydrate formation conditions at the tree during shutdown may require further tree insulation, methanol displacement within the cooldown time, or even methanol pretreatment prior to shutdown, while hydrate formation conditions at the flowline during shutdown may require dead oil displacement within the cooldown time.
Hernandez said the bowtie model is an effective tool for communication.
“In a snapshot, you have the event that you’re trying to prevent, whatever causes you have for that event, and whatever barriers you have to keep that event from happening. If that happens, what barriers do you have to prevent that event from propagating? [The bowtie model] has been a very useful tool for us.”
Communication with the operators is also a critical way to minimize risk. Hernandez said the company made it a priority for operators to understand the procedures for handling various flow-assurance-related situations, as well as the key performance indicators used to determine the effectiveness of those procedures. As flow assurance procedures and strategies are updated, Hernandez said it was important for everyone in an organization to know exactly what to do, particularly when risk events occur at a low frequency.
“Most of the times they want to follow the procedure,” she said. “They don’t just ignore the procedure. If the procedure is not being followed, it’s because the procedure is wrong, it’s too complicated, or there is some critical barrier that’s preventing that operator from actually using that procedure, so you have to make sure that the procedures make sense.”
Executing Offshore Projects More Efficiently
Offshore project execution enhancement ideas are highlighted for debottlenecking, gas-hydrate-induced pipeline vibration, and the design of subsea systems for efficient startup.
Hydrate-Induced Vibration in an Offshore Pipeline
A computational fluid dynamics model is proposed to analyze the effect of hydrate flow in pipelines using multiphase-flow-modeling techniques. The results will identify the cause of pipeline failure, regions of maximum stress in the pipeline, and plastic deformation of the pipeline.
Managing the Risk of Hydrates Offers Alternative to Avoidance Strategy
The 9th International Conference on Gas Hydrates featured discussions on key advancements in flow assurance, including the concept of risk management and anti-agglomerates being applicable strategies in transient operations.
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