Chalk reservoirs, due to their high porosity and very low permeability, represent one of the most interesting cases for engineering studies of carbonates. They exhibit complex fluid-rock interactions because of their reactive surfaces and dense porous medium. The reinjection of produced water is an attractive strategy for managing wastewater flow from oil wells. However, the complex composition of produced water, the reactive nature of carbonate rocks, and their low permeability create challenges related to permeability loss.
This study examines the stages of permeability change during core flooding experiments up to the point of complete clogging. A distinctive feature of this study is the presence of residual oil in the core samples, which simulates real reservoir conditions during produced water reinjection. The presence of residual oil is an additional factor influencing the change in core permeability, but there is no clear consensus in the research community on its impact on permeability during produced water injection.
All experiments were conducted in a core flooding system simulating well conditions in terms of pressure (170 bar) and temperature (70 ◦C). Produced water samples from the Dan field were used to replicate the chemical and thermodynamic processes occurring in a real well. The experiments identified three stages of permeability change: an initial increase in permeability (+12%), a period of pressure stabilization, and a subsequent decrease in permeability (− 8%) due to the formation of inorganic precipitates within the core channels.
The primary objective of the experiments is to investigate the relationship between permeability changes and the stages of reinjection, with a focus on the effects of residual oil. The study focuses on identifying the processes occurring up to the point of complete clogging, considering the impact of residual oil saturation in the chalk core samples. Image analysis using scanning electron microscopy, particle size measurement with a zeta-potential meter, and thermodynamic scale formation modeling with ScaleCERE software were employed to explain these processes.
Three stages of permeability change were identified during the injection of 200 pore volumes of produced water: increased permeability (+12%), pressure stabilization, and decreased permeability (− 8%). The positive influence of residual oil saturation on the filtration and storage properties of the reservoir was established, due to the mobilization of chalk core particles. Additionally, the theory of core channel clogging during the reinjection of formation water by the formation of inorganic precipitates within the channels was confirmed.
Understanding the causes of permeability reduction that occurred during the stage of permeability decrease enables the development of water purification methods specifically targeted at the causes of rock clogging. Predicting the process of injecting a mixture of produced and seawater will help in interpreting the data during disposal operations by injecting formation water into an injection well, and it will allow for the selection of effective measures to mitigate the impact on the reservoir.
As maritime technology advances, multi-energy ship microgrids (MESMs) are widely used in large cruise tourism. In this context, studying cost-effective and highly reliable energy system planning methods for MESMs in their entire lifespan becomes paramount. Therefore, this paper proposes a joint planning method for a MESM during its lifetime. Firstly, a long timescale coordinated planning and operation scheme is formulated with the aim of maximizing the Net Present Value (NPV) value, thereby reducing both project investment and energy supply cost. In addition, this paper introduces novel operation models that incorporate customer thermal comfort levels, considering thermal inertia, and ship navigation, accounting for the effects of waves and wind. These models enhance the flexibility and practicality of the planning process. Finally, to ensure the safe operation of vessels and alleviate the negative effects of uncertain wind and waves during ship navigation, a robust optimization (RO) approach is employed. A case study demonstrates the effectiveness of the proposed method, with several comparison analyzes further highlighting its advantages.
Seaports consume a large amount of energy and emit greenhouse gas and pollutants. Integrated multiple renewable energy systems constitute a promising approach to reduce the carbon footprint in seaports. However, the intermittent nature of renewable resources, stochastic dynamics of the demand in seaports, and unbalanced structure of seaport energy systems require a proper design of energy storage systems. In this paper, a framework for multi-objective optimization of hybrid energy storage systems in stochastic unbalanced integrated multi-energy systems at sustainable mega seaports is proposed to minimize life-cycle costs and minimize carbon emissions. The optimization problem is formulated with reference to the energy management of the integrated multi-energy system at the seaport and considering both distributed and centralized hybrid energy storage configurations. Wavelet decomposition and double-layer particle swarm optimization are proposed to solve the multi-objective optimization problem. The real power system of the largest port worldwide, i.e., the Ningbo Zhoushan Port, was selected as a case study. The results show that, with respect to a situation with no energy storage system, the proposed approach can save 81.29 million RMB in electricity purchases and eliminate approximately 497,186 tons of carbon emissions over the entire lifecycle of the energy storage system. The findings suggest that the proposed hybrid energy storage framework holds the potential to yield substantial economic and environmental advantages within mega seaports. This framework offers a viable solution for port authorities seeking to implement hybrid energy storage systems aimed at fostering greater sustainability within port operations.
Port Integrated Multi-Energy Systems (PIMES) play a critical role in advancing sustain-ability at ports. Assessing the dynamic contribution of PIMES to port sustainability is essential for guiding future developments. This research introduces an innovative multi-criteria dynamic sustainability assessment framework tailored to evaluate the performance of PIMES. The framework employs a diverse set of indicators covering multiple criteria to comprehensively assess different aspects of PIMES. A game theory-based combined weighting approach is uniquely applied to integrate subjective and objective evaluations, ensuring a balanced and robust assessment. Furthermore, the cloud model is utilized for an in-depth evaluation of the overall sustainability of PIMES, offering a novel perspective on managing uncertainty. The framework's applicability and effectiveness are demonstrated through a case study of the Ningbo-Zhoushan Port, with a sensitivity analysis of the indicators conducted to enhance reliability and confirm the robustness of the proposed method. The evaluation results indicate that during the development of the PIMES, the sustainability performance of the studied port improves progressively, with ratings of “average”, “poor”, “average”, “average”, “good”, and “excellent”. The sensitivity analysis shows that the sustainability of ports is most influenced by the failure loss rate and operation & maintenance cost of PIMES. This framework can serve as a decision-making tool for port authorities to enhance energy efficiency, reduce emissions, and achieve long-term sustainability objectives at ports.
The climate emergency has prompted rapid and intensive research into sustainable, reliable, and affordable energy alternatives. Offshore wind has developed and exceeded all expectations over the last 2 decades and is now a central pillar of the UK and other international strategies to decarbonise energy systems. As the dependence on variable renewable energy resources increases, so does the importance of the necessity to develop energy storage and nonelectric energy vectors to ensure a resilient whole-energy system, also enabling difficult-to-decarbonise applications, e.g. heavy industry, heat, and certain areas of transport. Offshore wind and marine renewables have enormous potential that can never be completely utilised by the electricity system, and so green hydrogen has become a topic of increasing interest. Although numerous offshore and marine technologies are possible, the most appropriate combinations of power generation, materials and supporting structures, electrolysers, and support infrastructure and equipment depend on a wide range of factors, including the potential to maximise the use of local resources. This paper presents a critical review of contemporary offshore engineering tools and methodologies developed over many years for upstream oil and gas (O&G), maritime, and more recently offshore wind and renewable energy applications and examines how these along with recent developments in modelling and digitalisation might provide a platform to optimise green hydrogen offshore infrastructure. The key drivers and characteristics of future offshore green hydrogen systems are considered, and a SWOT (strength, weakness, opportunity, and threat) analysis is provided to aid the discussion of the challenges and opportunities for the offshore green hydrogen production sector.
Hybrid testing, often referred to as hardware-in-the-loop, is when some parts of a complete system are modeled virtually and some parts are modeled experimentally, with information flowing back-and-forth between the virtual and experimental parts. Hybrid testing speeds up prototyping and testing. In this paper we outline the hybrid set-up for testing the performance of a hydraulic pump which is used as part of the power take-off system of the Wavepiston multi-body floating oscillating wave surge converter (OWSC). The motion of the OWSC is modeled in Orcaflex and the hydraulic system is simulated using Simscape. Due to the long stroke-length of the telescopic pump, a test rig handling only 1/3 of the stroke-length was constructed. The co-simulation, and linking to the test rig, is done using the Model.CONNECTTM and Testbed.CONNECTTM framework by AVL. The results obtained can be used for improving the numerical representation of the pump and validating models for the wear of the seals inside the pump.
We numerically simulate the hydrodynamic response of a floating offshore wind turbine (FOWT) using computational fluid dynamics. The FOWT under consideration is a slack-moored 1:70 scale model of the UMaine VolturnUS-S semi-submersible platform. The test cases under consideration are (i) static equilibrium load cases, (ii) free decay tests, and (iii) two focused wave cases of different wave steepness. The FOWT is modeled using a two-phase Navier-Stokes solver inside the OpenFOAM-v2006 framework. The catenary mooring is computed by dynamically solving the equations of motion for an elastic cable using the MoodyCore solver. The results are shown to be in good agreement with measurements.
This report includes a broad description of the findings from work package 2 in the EFFORT project and is made as the fulfillment of delivery L2.1 in the project. First an overall description of the Port of Hirtshals together with its infrastructure is given in chapter 1 together with some background aspect for the development of the Port of Hirtshals. In this chapter also the 5 companies who had shown their interest in participation in the project are described in more detail. Based on this as outcome of task 2.1 and described in chapter 2 an overall system architecture is set up for the existing industries at the Port of Hirtshals and next for the future expansion of the port. Based on the overall system architecture an adaptation of the system to the EU SGAM model is performed and explained. Then the overall set up of the data hub is briefly introduced, to see how it is related to the overall energy system set up. The final part documented for task 2.1 is two examples of sequence diagrams for first the processes in Forskerparken and next one which is valid for both the Fish Terminal, Lineage as well as Danish Salmon, since many of their electrical consuming processes here in an overall manner look the same.
In chapter 3 the base scenarios for the existing industries at Port of Hirtshals are set up. This is done based on information and wishes from the industries and the local Distribution System Operator (DSO), which is gained partly by bilateral discussions as well as on a workshop held with all the involved industries present at the same time. The scenarios will be described according to the IEC standard 62559-2, to ensure better utilization of the ideas in other projects, by applying a standard template known in this area.
Finally, in chapter 4 scenarios for the future expected extension of industries and activities at the Port of Hirtshals are set up. This is based on inputs from GPN, HH, NEN as well as Hjørring Municipality, Hirtshals Fjernvarme and from inputs from workshops with the existing industries at the port. Also here the IEC 62559-2 standard will be applied when describing the use cases.
The scenarios set up will later be used for the further development of the data hub, which is to be set up in the project, as well as for the model set up and control perspectives in the later WPs.
The cold ironing system is gaining interest as a promising approach to reduce emissions from ship transportation at ports, enabling further reductions with clean energy sources coordination. While cold ironing has predominantly been applied to long-staying vessels like cruise ships and containers, feasibility studies for short-berthing ships such as ferries are limited. However, the growing demand for short-distance logistics and passenger transfers highlights the need to tackle emissions issues from ferry transportation. Incorporating electrification technology together with integrated energy management systems can significantly reduce emissions from ferry operations. Accordingly, this paper proposes a cooperative cold ironing system integrated with clean energy sources for ferry terminals. A two-stage energy management strategy combining sizing and scheduling optimization is employed to reduce the port's emissions while minimizing system and operational costs. The proposed system configuration, determined through the sizing method, yields the lowest net present cost of $9.04 M. The applied energy management strategy managed to reduce operational costs by up to 63.402 %, while significantly decreasing emissions from both shipside and shoreside operations. From the shipside, emissions reductions of 38.44 % for CO2, 97.7 % for NOX, 96.69 % for SO2, and 92.1 % for PM were achieved. From the shoreside, the approach led to a 28 % reduction across all emission types. Thus, implementing cold ironing powered by clean energy sources is a viable solution for reducing emissions generated by ferry operations. The proposed energy management approach enables emissions reduction and delivering cost-effectiveness at ferry terminals.
The hybrid combination of hydrogen fuel cells (FCs) and batteries has emerged as a promising solution for efficient and eco-friendly power supply in maritime applications. Yet, ensuring high-quality and cost-effective energy supply presents challenges. Addressing these goals requires effective coordination among multiple FC stacks, batteries, and cold-ironing. Although there has been previous work focusing it, the unique maritime load characteristics, variable cruise plans, and diverse fuel cell system architectures introduce additional complexities and therefore worth to be further studied. Motivated by it, a two-layer energy management system (EMS) is presented in this paper to enhance shipping fuel efficiency. The first layer of the EMS, executed offline, optimizes day-ahead power generation plans based on the vessel's next-day cruises. To further enhance the EMS's effectiveness in dynamic real-time situations, the second layer, conducted online, dynamically adjusts power splitting decisions based on the output from the first layer and instantaneous load information. This dual-layer approach optimally exploits the maritime environment and the fuel cell features. The presented method provides valuable utility in the development of control strategies for hybrid powertrains, thereby enabling the optimization of power generation plans and dynamic adjustment of power splitting decisions in response to load variations. Through comprehensive case studies, the effectiveness of the proposed EMS is evaluated, thereby showcasing its ability to improve system performance, enhance fuel efficiency (potential fuel savings of up to 28%), and support sustainable maritime operations.