The Importance of Flow Assurance in the Oil and Gas Industry
What does the term, flow assurance, exactly entail? It’s important to learn more about and keep in mind when it comes to the oil and gas industry. Read more below.
The ever-increasing demand for energy, as well as the non-stop fluctuations in the prices of oil and natural gas, has called for an in-depth review of the existing production, transportation, and even storage technologies within the oil and gas sector. Ever since new technologies were introduced to develop oil and gas wells, they have significantly enhanced efficiency and production economics. The success these technologies are showing for both drilling and production operations is phenomenal.
Nevertheless, one major obstacle has reared its ugly head as organizations dig deeper underground and even underwater. And it has to do with precisely how to economically deliver precious hydrocarbon resources right from the reservoir to the final user. This challenge has led scientists, as well as oil and gas producers, to create a new term: ‘flow assurance.’
What is Flow Assurance?
Flow assurance is a term that originated in the 1990s and was coined by Petrobras. The term is translated from the Portuguese language – meaning ‘guarantee of flow.’ It ensures that fluids produced consistently by any fuel reservoir reliably reach the point of separation – without any hiccups – into separate discrete compounds.
In other words, flow assurance is the economical and highly successful flow of hydrocarbon streams or fluids from a reservoir to the point of sale. The focus of flow assurance is primarily on the entire engineering as well as product lifecycle, right from the reservoir and through processing and refining in order to ensure that hydrocarbons can be moved seamlessly from the reservoir to the reservoir without any interruption.
Flow assurance encompasses several specialized and discrete subjects, thereby bridging the complete series of engineering disciplines. Financial losses that occur from the damage of assets or production interruption resulting from flow assurance hazards can be enormous.
What Flow Assurance Covers
Flow assurance covers a wide range of flow-related issues, as stated by the American Petroleum Institute (API). This includes (in no particular order):
- Hydrates formation
- Wax formation
- Sand production
- Asphaltene formation
- Scale formation
- Materials-related issues
The hindrances to flow may differ, depending on whether the hydrocarbons produced are gas or oil. However, they may coincide in a few aspects.
For instance, two key obstacles usually encountered during oil production are asphaltene and wax deposits. However, in gas production, the formation of hydrates is a crucial obstacle.
What are the Obstacles to Flow Assurance?
It is well known that during production from a gas condensate reservoir, the #1 obstacle encountered here has to do with how to expressly deliver the fluid from the wells to the processing facility with very minimal pressure drop.
Pressure drop within a multi-phase flow is a primary function of the liquid holdup and flow pattern. Therefore, to accurately predict pressure drop, it is essential to determine the liquid hold up as well as the flow pattern inside the pipeline.
Slug flow occasionally occurs within the multi-phase flow, particularly in most offshore production facilities. And this usually includes seabed pipelines as well as risers to the processing platform. For appropriate processing facility design – which includes the accurate sizing of separators and slug catchers – the correct prediction of slug frequency is highly essential.
The presence of free water within gas production pipelines significantly improves the formation of hydrates under specific temperature and pressure conditions. The formation of hydrates will partly or wholly block the fluid flow in pipes, which brings about reduced well production as well as backpressure on the wellhead.
Hydrates formation will destroy the well in a worst-case scenario. The accurate prediction of hydrates formation within pipelines helps evaluate the problem and select the ideal solution for solving it.
When liquid accumulates inside pipelines, it leads to a significant increase in pressure drop, translating to loss in energy in most cases. However, this considerable loss must be compensated, thereby resulting in a much higher cost.
Accumulated water within pipes also accelerates the rate of corrosion of the pipelines. This liquid accumulation should be removed – from time to time – from the pipe, using what is known as a ‘pig.’
A pretty solid sphere with its diameter just slightly less than the diameter of the pipe is readily inserted into the pipeline and then pushed using a pressure source. The pressure sweeps the accumulated liquid within the pipeline ahead of it. It is best to accurately estimate the swept liquid in order to decide whether the existing facilities can easily handle the slug flow from the pig or if an external handling facility may have to be called in to process as well as store the slug.
One thing that should always be at the forefront of this activity is the timing of any pigging operation. This vital parameter – in this particular process – can be used to evaluate the pig reaching the very end of the pipeline.
If a mistake occurs and the predetermined time is somehow exceeded, the pig will get stuck in the pipeline. And retrieving it may require other procedures, which add to the overall cost of production.
Oil and gas companies should always have – and regularly update – prevention strategies that stop issues from occurring. The strategies negate the need for expensive and complex remediation further down the line. And it also mitigates the shutdown time that may arise as a result of blockages.
Maintaining the operation of vital and of the utmost importance. And every on-site operator must be mindful of the entire procedures involved under the prevention strategy.
The strategy should also detail the steps to take if any breakdown occurs, how to avoid slugging, and the optimal flow rate.
The internalization of chemicals is one of the significant parts of any flow assurance prevention strategy. And all chemical strategies should aim for a minimum of 50 percent efficiency in the prevention of issues that may halt operations. Every chemical intervention calls for a comprehensive evaluation of the package’s performance and must be quickly delivered upstream of the issue.
The chemical themselves mustn’t essentially alter the conditions of the pipeline or react explosively with other chemicals in the fuel.
Regular pipe/equipment maintenance to avoid flow assurance failure is a must. It should be part of the prevention strategies incorporated very early in the design process.
The importance of flow assurance in the oil and gas industry cannot be overemphasized. Flow assurance failure can result in catastrophic events, including loss of resources and even life.
Therefore, implementing regular flow assurance studies and up-to-date data to assess all existing gathering systems so that future drawbacks can easily be forecasted and measures put in place to prevent such occurrence is essential.
Pigging operations must also be carried out from time to time in order to boost the readability and integrity of the pipeline.
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