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PETROMAKS2-Stort program petroleum

New Hydrate Management: New understanding of hydrate phenomena in oil systems to enable safe operation within the hydrate zone

Alternative title: Fremtidens hydratkontroll: Ny forståelse av hydratfenomener i oljesystemer for å sikre trygge operasjoner innenfor hydratlikevektsområdet

Awarded: NOK 9.6 mill.

Gas hydrates can plug pipelines and process equipment and is one of the biggest challenges in oil and gas production. The traditional methods for handling gas hydrates contribute to a significant part of the emissions from the petroleum sector, mainly through the use of large amounts of heat and chemicals. A recent case study concluded that CO2 emissions from oil production can be reduced by 20-30% if producing completely without using traditional hydrate management methods*. However, not all fields will be able to save the same amount, and not all fields need extensive hydrate protection. There is still a great need and interest in reducing both chemical and energy use in connection with gas hydrates. Some oils contain naturally occurring hydrate active components that prevent hydrate problems, but these components have not yet been identified. In this project, the aim was to investigate if Fourier Transforme Ion Cyclotron Resonance Mass Spectromery (FT-ICR MS) could be used to identify the gas hydrate properties of crude oils. The work done consisted of analysing samples from a range of different crude oils that were exposed to gas hydrates. Furthermore, accumulation of gas hydrate active oil components were attempted by modifying a procedure found in the literature. The spectra were analyzed using advanced multivariate data analysis and machine learning. The goal was to get one step closer to identifying the hydrate active components that are responsible for non-plugging crude oil systems. This knowledge can be used to develop methods that can significantly reduce the environmental impact of oil production, by avoiding the use of heat and chemicals. Several oils with different hydrate properties were tested far, and the first analyses indicate that it is possible to accumulate the hydrate-active components. By adding the accumulated components to an oil, we have managed to change the oil's hydrate properties in a positive direction. We have developed unique new methods within multivariate data analysis, which will help us understand the link between oil composition and hydrate properties. We will analyse more oils, and continue to look for the "needle in the haystack", i.e. the hydrate-active components that make crude oils non-plugging. If we succeed, this can be an important step towards more sustainable energy production. The final results from the project indicated that although the FT-ICR MS is a formidable instrument, extracting trends in terms of gas hydrate properties for crude oils was challenging. One reason was the relatively low number of samples, and the other was that the components being hydrate active can differ from one oil to another, thus the location of the responses may be at different places in the spectra. Nevertheless, the project, through the PhD candidate work did manage to indicate molecular structures/compositions that could be related to being gas hydrate active. In addition to the FT-ICR MS and gas hydrate experiments, so called “wheel flow loop” tests were performed on 7 crude oils, at different water cuts and procedures. The results were then used to develop algorithms for extracting relevant data such as gas solubilities, hydrate curve dynamics, hydrate formation and dissociation kinetics and flow properties. The algorithms developed were considered sufficiently novel to be submitted for publication. * Heiner Schümann, November 2021, "Feasibility and environmental analysis for a 100 km tie-back solution with cold-flow", webinar in LowEmission project (p.nr. 296207)

- Have indicated that gas hydrate active components can be accumulated using a “spiking procedure”, described in the published work. - Applied standard and updated models and algorithms to evaluate FT-ICR MS spectra on crude oils on new applications - Developed multi-block methods to analyse spectra from different sources and trained models to predict density of crude oils. Results showed that multi-block method was superior to predicition based on only one type of spectra. Published in paper. - New algorithms were developed, based on state-of-the-art knowledge to extract data from wheel flow loop tests that were not previously done. This algorithm will be used by SINTEF in the future and will provide increased value to industry end users of SINTEFs experiments. It will be published in open access journal. - 5 new researchers have been introduced to gas hydrate research and have gained training in various aspects ranging from conducting experiments, to development of thermodynamic and kinetic models. The increased knowledge on gas hydrates will gain SINTEF, NMBU and the industry partners in the future. - SINTEF and NMBU have gained increased knowledge on each others competences and will seek further cooperation in future projects.

For the petroleum industry, risk-based hydrate management can be a viable strategy for significantly widening the operational window. The traditional approach has been to avoid entering the hydrate region (high pressure and low temperature) altogether by temperature control (insulation and heating), chemicals (methanol and glycols) and pressure control. Although ensuring safe operations these remedies are costly for longer and colder transport conditions and not necessarily environmentally sound. This project will help meet demands of marginal field developments and operations in Artic areas by advancing the new fundamental knowledge of gas hydrate properties and develop methods for risk assessment and cost-effective hydrate management. From field experience, it is known that some oil pipelines are easily plugged by gas hydrates while others are transportable. This is commonly accepted to be due to naturally occurring polar components in the crude oils. A main goal is to combine the increased resolution of mass spectrometry (using the SINTEF owned FT-ICR MS) and advanced multivariate data analysis, block chain and machine learning to identify the hydrate-active components in crude oils. Hydrate properties in terms of plugging risk and transport properties will be measured for a number of crude oil systems (tentatively 30), and extraction of hydrates for analysis will be done. Prediction tools will be developed, relating the structure of possible hydrate active components to the hydrate properties, thus providing new understanding of gas hydrates in crude oil systems and serve as basis for developing new guidelines for risk-based hydrate management. Ultimately the results can be used for input and validation of multiphase flow models necessary for prediciton of safe operation areas for transport within the hydrate region. Industri partners will play an active role in the project with expertise and oil samples. A reference group with experts will be established.

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Funding scheme:

PETROMAKS2-Stort program petroleum