The upstream offshore multi-phase well-pipeline-riser installations are facing huge challenges related to slugging flow: An unstable flow regime where the flow rates, pressures and temperatures oscillate in the multi-phase pipelines. One typical severe slug is induced by vertical wells or risers causing the pressure to build up and hence originates the oscillating pressure and flow. There exist many negative consequences related to the severe slugging flow and thus lots of investments and effort have been put into reducing or completely eliminating the severe slug. This paper reviews in detail the state-of-the-art related to analysis, detection, dynamical modeling and elimination of the slug within the offshore oil & gas Exploration and Production (E&P) processes. Modeling of slugging flow has been used to investigate the slug characteristics and for design of anti-slug control as well, however most models require specific facility and operating data which, unfortunately, often is not available from most offshore installations. Anti-slug control has been investigated for several decades in the oil & gas industry, but many of these existing methods suffer the consequent risk of simultaneously reducing the oil & gas production. This paper concludes that slug is a well defined phenomenon, but even though it has been investigated for several decades the current anti-slug control methods still have problems related to robustness. It is predicted that slug-induced challenges will be even more severe as a consequence of the longer vertical risers caused by deep-water E&P in the future.
This paper investigates the challenges associated with remote harmonic compensation in offshore wind power plants through long cables and transformers. The interaction between the grid network and the wind power plant network can lead to the amplification of certain harmonics and potentially resonant conditions. Hence, the plant developer is required to maintain the harmonic distortion at the point of common coupling within the planning level limits using harmonic compensation, which is usually done by static filters. In this paper an active damping compensation strategy with a STATCOM using emulation of using emulation of resistance at the harmonic frequencies of concern is analyzed. Finally the results are demonstrated using time domain simulations in PSCAD.
The existence of a sense of common or community interests is a prerequisite to establishing an order in a society, national or international. In this connection, it is notable that the protection of community interests is increasingly important in international law and the law of the sea is no exception. The increasing need for protecting community interests necessitates a new paradigm in the law of the sea. The legal issues regarding the marine Arctic should also be considered in the context of changing paradigms in the law of the sea. Thus this article seeks to overview principal issues of the international law governing the marine Arctic from the viewpoints of a dual paradigm, that is, the law of divided oceans (paradigm I) and the law of our common ocean (paradigm II).
To clean the produced water is always a challenging critical issue in the offshore oil & gas industry. By employing the plant-wide control technology, this paper discussed the opportunity to optimize the most popular hydrocyclone-based Produced Water Treatment (PWT) system. The optimizations of the efficiency control of the de-oiling hydrocyclone and the water level control of the upstream separator are discussed and formulated. Some of our latest research results on the analysis and control of slugging flows in production well-pipeline-riser systems are also presented. The ultimate objective of this research is to promote a technical breakthrough in the PWT control design, which can lead to the best environmental protection in the oil & gas production, without sacrificing the production capability and production costs.
The impact of climate change in the Arctic Ocean such as ice melting and ice retreat facilitates natural resources extraction. Arctic fossil fuel becomes the drivers of geopolitical changes in the Arctic Ocean. Climate change facilitates natural resource extractions and increases competition between states and can result in tensions, even military ones. This article investigates through a political and legal analysis the role of China as an emerging regulatory sea power in the Arctic Ocean given its assertive “energy hungry country behaviour” in the Arctic Ocean. The United Nations Convention on the Law of the Sea (UNCLOS) and the Arctic Council (AC) are taken into consideration under climate change effects, to assess how global legal frameworks and institutions can deal with China’s strategy in the Arctic Ocean. China’s is moving away from its role as “humble power” to one of “informal imperialistic” resulting in substantial impact on the Arctic and Antartic dynamism. Due to ice-melting, an easy access to natural resources, China’s Arctic strategy in the Arctic Ocean has reinforced its military martitime strategy and has profoundly changed its maritime military doctrine shifting from regional to global in the context of UNCLOS. In particular, it is wondered, what China understands about the public order dimension of UNCLOS. The article concludes that despite China’ assertive behaviour towards the Arctic environmental ocean and its rise as global sea power, for the time being, China cannot be considered as a variable for Arctic security as there are no sufficient legal and policy objective elements to adduct that it constitutes a threat to Artic ocean security.
The global society faces an existential threat if it fails to meet current and future material needs of its populations, while staying within the carrying capacity of our planet. An approach that has been put forwards to address this complex challenge is to aim to close our society's material flows through introduction of a Circular Economy (CE). This paper provides an extensive literature review to understand the evolution of material circularity concepts and strategies, and their potential for increasing material efficiency and reduce environmental impacts towards meeting the material needs of our societies in an environmentally sustainable manner. Based on the review it can be concluded that CE may have a strong potential to help address the challenge. However, this requires broadening the focus of CE from technical and economical to political and socio-cultural dimensions, adopting a whole-systems approach, aiming to redesign economic and social relations to not just reduce the impact humanity has on the environment but actually achieve a balance in human-nature relations with a planetary boundary thinking. Pursuing purely technical and economic avenues to implement CE for increasing material circulation and sustainable growth on the foundation of our current linear economic system, will not achieve its full potential. It will not be sustainable but continue to produce the challenges that we currently have.
Reverse Logistics (RL) of end-of-use/end-of-life products has become a vital part of circular economy practices for manufacturers. However, significant quantities of resources are still landfilled instead of being recovered. With mounting pressure on businesses to address the sustainability crises (resources, climate change, waste, toxicity) on account of the take-make-dispose-based linear economy, companies today realise the importance of RL but face several barriers to implementing it, including a lack of knowledge. Although several studies have investigated different aspects of RL in various industries in different country settings, less attention has been devoted to developing a systematic and holistic approach for designing and implementing RL. To address these gaps, this paper reviews 116 scholarly articles published between 2011 and 2021 to identify attributes related to the design and implementation of RL systems. Based on a systematic literature review, a conceptual framework is presented covering the key activities, drivers and barriers, stakeholder engagement and performance management in RL. Such a framework can support companies evaluate different approaches and strategies, as well as the opportunities and challenges of designing and implementing RL and transitioning towards a Circular Economy.
The levelized costs of energy (LCoE) of wave power is still not fully competitive with other sources of renewable energy. However, wave energy is partly in a different phase than other renewable energy types and could thus contribute to a better predictability and smoothed power output. This work focuses on co-location of wave and wind power by investigating the intermittency of wind and waves power based on measured historical data from several hundreds of locations worldwide. Employing wind power curves and wave power matrices, the sites are evaluated based on several different metrics. The results indicate that there are several spots where wave power has a much lower intermittency than wind power providing reliable energy supply. Best sites for co-location in terms of energy yield were found in North-Western Europe. However, both wind and wave production have the same seasonal variability in these sites. Only a handful of sites found in California showed the possibility of seasonal power smoothing using the combination of wind and wave.
Reduction of carbon emissions is a societal challenge that demands concerted efforts. The maritime industry is no exception. This paper takes an ecosystem perspective and considers the question of how to enact the green transition of the maritime industry and explore the barriers and enablers of that goal. To this end, we conduct an exploratory case-study to investigate the maritime value chain by focusing on 9 major stakeholders and conducting more than 20 interviews. Our study reveals four continuous enablers and two essential enablers to establishing a functional green maritime ecosystem.
Ship collision with offshore installations is one of the key concerns in design and assess of platforms performance and safety. This paper presents an analysis on collision energy and structural damage in ship and offshore platform collisions for various collision scenarios. The platform or rig is treated as either rigid or flexible and its sensitivity on collision energy and structural damage is studied. An application example where an ice-strengthened supply vessel collides against a jack-up rig is analysed and the crushing resistance of the involved thin-walled structures is evaluated.