bluuebunny/crossref_metadata_2025 huggingface dataset:
Concurrent 13. Presentation for: Exploration and appraisal year in review 2021
Authors: Craig Adam
Published: June 2022

Presented on Wednesday 18 May: Session 13 Petroleum exploration and appraisal activity increased in 2021. Exploration spend increased for the year, continuing a positive trend. Onshore exploration and appraisal activity continues to dominate the petroleum exploration scene in Australia. Positive indications of increased work program bids (wells, seismic and spend) are, however, tempered by the downward trend of total exploration acreage (by area) and new acreage awards. In addition to petroleum exploration acreage, greenhouse gas sequestration acreage was released across Australia in 2021. Twenty-nine exploration wells were drilled in the year compared to twenty-five in the previous year. Eight conventional petroleum discoveries were reported, with the Artisan-1 discovery in the Otway Basin being the only offshore discovery. The Lockyer Deep-1 gas discovery in the Northern Perth Basin continues the exploration success of the Permian Kingia and High Cliff Sandstone play. The Cooper–Eromanga Basin continues to yield discoveries with the Odin-1, Rosebay-1, Lowry South, Liger-1 and Chimera-1 discoveries reported for the year. Thirty-one appraisal wells were drilled for the year with significant activity in the Northern Perth Basin, Cooper-Eromanga Basin and Bowen-Surat Basins. Exploration and appraisal drilling also continued in the Beetaloo Sub-basin with the drilling of the Tanumbirini-2H, Tanumbirini-3H and Carpentaria-2/2H wells during the year. To access the presentation click the link on the right. To read the full paper click here
Concurrent 13. Presentation for: PESA Australia business environment review 2021
Authors: Bell Candice
Published: June 2022

Presented on Wednesday 18 May: Session 13 With a backdrop of energy transition and an accelerating need to decarbonise, the oil and gas business environment was complex and conflicted through 2021. The complexity of the energy transition was continually highlighted by academia and international agencies. While asserting gas and LNG as a fuel critical to the energy transition, they continued to warn that the transition away from fossil fuels is not occurring fast enough to arrest catastrophic climate change. International cooperation culminating at COP26 somewhat faltered in the face of the immense challenges the energy transition poses. Complexity was also demonstrated through the rise in LNG spot prices as Asia’s demand for energy rebounded. Though high spot LNG prices through this period proved lucrative for producers, the surge in prices pushed some Asian markets back to emission-intensive yet low-cost coal for energy generation, signalling the volatility and challenges of LNG’s position as an energy transition fuel. Conflict was seen when environmentally focused activist investors disrupted business-as-usual operations for several Australian and international firms, with all signs pointing to an intensification of this trend in the coming years. In response, capital markets rallied behind low-carbon energy investments with trillions of dollars flowing towards renewables, hydrogen and CCS projects. Finally, to compound the complexity of the myriad external forces, oil and gas firms coalesced around four key decarbonisation responses. Oil and gas firms focused efforts on: (1) strengthening and refining net zero commitments; (2) operational decarbonisation including CCS investment; (3) investment in low-carbon fuels including hydrogen; and (4) consolidation, to strengthen balance sheets, build business model resilience and diversify their portfolios. To access the presentation click the link on the right. To read the full paper click here
Concurrent 15. Presentation for: INPEX-led Ichthys Joint Venture – developing a dynamic adjustment area to identify, time, duration and potential exposure periods related to a 2D seismic survey offshore Western Australia
Authors: Prout Jake
Published: June 2022

Presented on Wednesday 18 May: Session 15 The oil and gas industry is striving for effective consultation between titleholders and commercial fishing stakeholders. Recent developments in cross-industry consultation have resulted in frameworks to provide an adjustment (compensation) claim process, where short-term displacement of fishers and reduction of catch coincident and following marine seismic survey activities may occur. 3D seismic surveys are undertaken more intensively, in geographically smaller areas and shorter time periods. This allows for discreet areas and periods to be defined for the applicability of a claim when fishing catch rates or displacement may occur. By contrast, 2D seismic surveys can be undertaken at regional scales with long sail line transects. These result in a survey vessel being active in an area of potential acoustic influence for infrequent and short periods of time, thus making justification for claims, for loss of catch or displacement, over the full survey area and full acquisition period challenging. To address this challenge a novel approach was developed to determine a dynamic area, based on where and when a survey vessel was operating the seismic source. INPEX utilised the 10 nautical miles (nm) × 10 nm geospatial grid data set provided by Department of Primary Industries Resources and Development, for commercial fishers to report catch effort. The methodology used modified navigation files, to determine the frequency, duration and number of times a fishing block was intersected during the survey. The resulting data provided an ‘adjustment area’ and ‘exposure date’ which could then be referred to as a basis for claim. To access the presentation click the link on the right. To read the full paper click here
Concurrent 18. Presentation for: Simplicity and digitalisation – using GIS to reduce design and operation costs in gas gathering systems
Authors: Meynink Alex
Published: June 2022

Presented on Wednesday 18 May: Session 18 With the drive to continually reduce the cost of connecting new Coal Seam Gas (CSG) wells, Worley developed new methodologies using commercial off-the-shelf software, and custom development, to automate engineering and improve operational efficiency for pipelines and gathering systems. One of the recent developments is an automated and data-driven approach to produce Gathering Network Diagrams (GNDs), an alternative to conventional Piping & Instrumentation Diagrams (P&IDs). On a recent project, Worley implemented a GND workflow capable of showing ~40 wells per A3 deliverable in conformance with intelligent drafting standards. This reduced ~2000 as-built P&IDs to ~200 GNDs (and associated standard details) with a significant improvement in quality and usability. Prior to generation, a site walkdown was conducted to address mismatches between as-built P&IDs, Geographic Information System (GIS) and what was actually installed at site. Our client now has a suite of GNDs that match the installed asset and are produced from the corporate GIS database, essentially their Digital Twin. Worley then focused on integrating flow assurance software with GIS allowing data-driven execution of future design packages to be incorporated into the master GNDs. We successfully integrated with PipeSIM and GAP, allowing for seamless transfer of hydraulic inputs from GIS to the modelling software. Engineers can now synchronise the confirmed process design back to GIS without producing red-lined and/or CAD-drafted deliverables which greatly improves efficiency and reduces human error. This paper demonstrates how digital automation can be applied to the CSG industry to significantly reduce cost and schedule whilst enabling data-driven operational efficiencies. To access the presentation click the link on the right. To read the full paper click here
Concurrent 21. Presentation for: The Petrel Sub-basin: a world-class CO
Authors: Johnstone Rosie
Published: June 2022

Presented on Thursday 19 May: Session 21 In 2021, the Australian Government announced a round of offshore greenhouse gas acreage release, including an area where research by Shell/CSIRO in 2016/2017 indicated close to 1 Gt carbon dioxide storage potential within the Mesozoic sediments of the Sandpiper, Elang and Plover Formations of the Petrel Sub-basin. The joint Shell/CSIRO study assessed key containment issues (legacy wells, potentially conductive faults, top seal extent) and storage formation connectivity. To study containment risk, CSIRO assessed a single injection well scenario and concluded that injection of up to 20 MTPA would not create geomechanical failure. Based on these findings, a ~5000 km2 area of interest southeast of the Petrel Field was proposed as suitable for injection in the Plover/Elang formations. The Shell team constructed topographical dynamic models at five potential locations. Three further models were built to simulate a base case and two end-member scenarios: (1) high permeability (leak point risk) and (2) low-pressure dissipation (top seal risk). The study showed that the development of two injector wells at one of the locations could safely and conservatively store 149 Mt, injected over a period of 30 years. Similar capacity is expected at four out of the five locations identified within the investigated area. Expansion to >2 injection wells per location, additional injection into the Sandpiper Formation and expansion to the west of the initially mapped focus area all point to achievable gigatonne storage potential. The joint study significantly expanded the understanding of the storage capacity, with recommendations for further data acquisition in both greenhouse gas (GHG) permits (GHG21-1 and GHG21-2). To access the presentation click the link on the right. To read the full paper click here
Concurrent 22. Presentation for: Strength in numbers: how the different satellite systems used to monitor methane emissions from space have different, yet complementary, capabilities to help the oil and gas industry meet its decarbonisation goals
Authors: Gauthier Jean-Francois
Published: June 2022

Presented on Thursday 19 May: Session 22 Satellites are a powerful tool in monitoring methane emissions around the world. In the last 5 years, many new systems have been both announced and deployed, each with different capabilities, and designed for a specific purpose. With an increase in options also comes confusion as to how these systems can and should be used. This paper will examine how these systems complement each other’s strengths and weaknesses to provide actionable insight to the oil and gas industry. The performance parameters of several current and future satellite systems will be presented and compared, supported with recent examples when available. The importance of factors like frequency of revisit, detection threshold, precision, and spatial resolution will be discussed and contrasted with the needs of the oil and gas industry in gaining a more complete understanding of its methane emissions, in providing key information to stakeholders, and in enabling action to mitigate emissions. Results from GHGSat’s second generation of high-resolution satellites displaying measurements of methane plumes at oil and gas facilities around the world will be presented to demonstrate some of the advantages of the technology. These two satellites, GHGSat-C1 and C2 (Iris and Hugo), were launched in September 2020 and January 2021, respectively. Another eight satellites are planned to be launched by mid-2023. Finally, the ability of these systems to work together and complement each other’s capabilities, and some of the analytics tools used to augment the data, will be presented. To access the presentation click the link on the right. To read the full paper click here
Concurrent 24. Presentation for: Greenhouse gases emissions evaluation for prospective energy projects
Authors: Ang Emelyn
Published: June 2022

Presented on Thursday 19 May: Session 24 Greenhouse gas (GHG) inventory assessment, monitoring and auditing is becoming increasingly routine in oil and gas project evaluations. Already, some companies carry an ‘internal’ carbon cost reflected in projected capital and operational expenditure. Early evaluation allows for optimal planning of GHG mitigation and economic analysis inclusive of carbon costs, allaying concerns of investors and lenders. The challenge in evaluating pre-development, however, is the lack of real data and thus, uncertainties in field production. In this paper, we demonstrate the use of a Monte Carlo probabilistic method to better account for uncertainties in production, gas-oil ratio (GOR) and operation loads in a case study of a prospective oil field in offshore Western Australia. We compared the results to the scenario-based deterministic GHG emissions evaluation of the same field and found the deterministic estimates to be extreme representatives of the range of possible emission quantities, due to GOR and production uncertainties. From a breakdown of annual emissions, we also identified the emissions from flaring of excess natural gas to be one of the most significant mitigatable sources of emissions, due to the unexpectedly large production of gas over the project lifetime. Avoiding the flaring of excess gases alone could reduce the project’s emissions by ~44%. Through identifying these key sources and uncertainties, we are able to flag such unexpected, mitigatable sources of emissions at an early stage and provide a representative range of projected emissions, thus assisting the operator to make informed decisions in the field development. To access the presentation click the link on the right. To read the full paper click here
Geoscience Poster G5: Stratigraphic framework and structural architecture of the Upper Cretaceous in the deep-water Otway Basin – implications for frontier hydrocarbon prospectivity
Authors: Nicholson Chris
Published: June 2022

Poster G5 Geoscience Australia has undertaken a regional seismic mapping study that extends into the frontier deep-water region of the offshore Otway Basin. This work builds on seismic mapping and petroleum systems modelling published in the 2021 Otway Basin Regional Study. Seismic interpretation spans over 18 000 line-km of new and reprocessed data collected in the 2020 Otway Basin seismic program and over 40 000 line-km of legacy 2D seismic data. Fault mapping has resulted in refinement and reinterpretation of regional structural elements, particularly in the deep-water areas. Structure surfaces and isochron maps highlight Shipwreck (Turonian–Santonian) and Sherbrook (Campanian–Maastrichtian) supersequence depocentres across the deep-water part of the basin. These observations will inform the characterisation of petroleum systems within the Upper Cretaceous succession, especially in the underexplored deep-water region. To access the poster click the link on the right. To read the full paper click here
Geoscience Poster G13: A regional strike-slip fault under the Canning Basin
Authors: Zhan Yijie
Published: June 2022

Poster G13 Gravity data in the Canning Basin exhibit a northeast-trending linear feature that offsets a gravity ridge in the vicinity of the Jurgurra–Mowla Terraces with a displacement of about 30 km. The sharp displacement is aligned with similar disruptions on the Lennard Shelf to the northeast and Broome Platform to the southwest. The northeast part of the lineament also shows an anomalous offset on aeromagnetic images. However, the lineament does not correspond to fault displacement within the sedimentary succession of the Canning Basin based on seismic profiles. The geophysical responses to the linear feature vary in different areas, possibly caused by the different thickness of overlying sedimentary rocks across the basin. The lineament is interpreted as a left-lateral strike-slip fault that pre-dates the Canning Basin to account for the lack of seismic responses in the sedimentary section. This northeast-trending fault lies in the basement and might have originated during one of the younger Proterozoic to earliest Paleozoic orogenies pre-dating the Canning Basin. The northeast-oriented fault in the basement was orthogonal to the strike of the basin, thus was less likely to have significant impact on the basin deposition compared to the northwest-oriented faults, such as the Pinnacle and Fenton Fault system. However, these perpendicular features probably created a deeply seated crustal weakness near the intersection where the cluster of lamproite pipes of the Ellendale field intruded during the Miocene. To access the poster click the link on the right. To read the full paper click here
Engineering Poster E3: Developing Australia’s underground hydrogen storage through demonstration
Authors: Watson Max
Published: June 2022

Poster E3 For Australia to capitalise on the growing hydrogen (H2) economy, the current capability gap for large-scale, secure and cost-effective H2 storage must be addressed. Large-scale underground hydrogen storage (UHS) in porous reservoirs offers the required capacity to balance discrepancies between demand and supply over seasonal durations, and support decarbonisation and security in Australia’s energy system. This becomes essential for export and domestic markets from 2030 onwards. UHS in depleted gas fields can address the infrastructure and safety challenges, as well as supporting long-term supply security while decreasing delivery price through economies of scale. However, the technical readiness for Australia’s industries to undertake UHS is low, with scientific challenges around how stored H2 interacts with subsurface rocks and fluids, and how this impacts the storage efficiency. A commercially relevant demonstration of UHS is essential for providing the knowledge and confidence for large investment into commercial scale UHS. CO2CRC and CSIRO are collaboratively developing such a demonstration, utilising data and learnings from the Otway International Test Centre, as a proxy for commercial-scale UHS operations. To access the poster click the link on the right. To read the full paper click here
Engineering Poster E4: Strength in numbers: how the different satellite systems used to monitor methane emissions from space have different, yet complementary, capabilities to help the oil and gas industry meet its decarbonisation goals
Authors: Gauthier Jean-Francois
Published: June 2022

Poster E4 Satellites are a powerful tool in monitoring methane emissions around the world. In the last 5 years, many new systems have been both announced and deployed, each with different capabilities, and designed for a specific purpose. With an increase in options also comes confusion as to how these systems can and should be used. This paper will examine how these systems complement each other’s strengths and weaknesses to provide actionable insight to the oil and gas industry. The performance parameters of several current and future satellite systems will be presented and compared, supported with recent examples when available. The importance of factors like frequency of revisit, detection threshold, precision, and spatial resolution will be discussed and contrasted with the needs of the oil and gas industry in gaining a more complete understanding of its methane emissions, in providing key information to stakeholders, and in enabling action to mitigate emissions. Results from GHGSat’s second generation of high-resolution satellites displaying measurements of methane plumes at oil and gas facilities around the world will be presented to demonstrate some of the advantages of the technology. These two satellites, GHGSat-C1 and C2 (Iris and Hugo), were launched in September 2020 and January 2021, respectively. Another eight satellites are planned to be launched by mid-2023. Finally, the ability of these systems to work together and complement each other’s capabilities, and some of the analytics tools used to augment the data, will be presented. To access the poster click the link on the right. To read the full paper click here
Engineering Poster E11: Using unsupervised machine learning to identify risk of failure at ageing oil and gas assets
Authors: Manchanda Uday
Published: June 2022

Poster E11 Asset integrity management of ageing oil and gas assets is an ongoing challenge. This paper uses unsupervised algorithms (i.e. clustering technique) to identify carbon steel piping with increased probability of failure due to various internal corrosion mechanisms. The application used over 20 variables including wellhead planktonic bacterial counts, Fe2+ levels, oil and water production rates, historical Non-Destructive Testing (NDT) records, remaining life of downstream equipment, previous remediation data and geographical location data. An unsupervised machine learning clustering algorithm was written grounded in mathematical techniques of Principal Component Analysis (PCA) and k-means clustering. The probabilistic algorithm identified implicit patterns, which were then used to identify critical and non-critical piping clusters. Outputs from the clustering model were used to prioritise field measurements, and while these are ongoing there appears to be a good agreement with model predictions. The paper further discusses the measures that have a higher impact on the classification accuracy of the algorithm. To access the poster click the link on the right. To read the full paper click here
ESG Poster ESG5: An integrated approach to environmental assessment for decommissioning outcomes
Authors: Mayboehm Louise
Published: June 2022

Poster ESG5 As the Esso/BHP infrastructure in Bass Strait is prepared for decommissioning, it is imperative to develop an enhanced understanding of the environment that has evolved around the infrastructure over the past 50 years of production operations. To meet this need, Esso is progressing an integrated environmental assessment program. The first stage of the program recognised that Esso held a wealth of underwater remotely operated vehicle (ROV) imagery collected over many decades of routine inspections. Working in partnership with third-party marine scientists and biologists, the ecological value of this imagery was assessed. Approximately 1000 h of subsea imagery was analysed to identify species to the lowest possible taxa. To supplement this information, Esso then undertook comprehensive offshore environmental surveys, collecting further underwater imagery to assess marine biota, fish and benthic communities during the summer of 2020/2021. Esso also engaged a leading Australian research organisation to design an environmental survey for the collection and analysis of sediment samples around targeted infrastructure, including reference sites, to increase our understanding of the potential impacts different decommissioning options may have, including disturbance and resuspension of sediments. This integrated approach to environmental assessment has enabled industry, leading marine scientists and research organisations to work collaboratively to better understand the ecological role of oil and gas infrastructure in Bass Strait. This knowledge will assist in identifying optimal decommissioning outcomes for all infrastructure types. To access the poster click the link on the right. To read the full paper click here
ESG Poster ESG10: Key lessons in planning for proactive decommissioning – a review of the Thevenard Island decommissioning project
Authors: Boisvert Michael B.
Published: June 2022

Poster ESG10 Chevron Australia Pty Ltd (CAPL) has operated an oil and gas production facility on Thevenard Island (TVI), a gazetted Nature Reserve, since 1988 on behalf of the TVI Joint Venture. CAPL is currently decommissioning the asset following cessation of production in 2014. Decommissioning activities include plugging and abandonment of onshore and offshore production wells, decommissioning onshore infrastructure and facilities, decommissioning offshore platforms and pipelines, and remediating and rehabilitating the terrestrial environment. CAPL is currently undertaking decommissioning and retirement of its facilities on TVI, including remediation and rehabilitation activities. CAPL is committed to progressing the decommissioning and rehabilitation activities in a timely manner to deliver positive outcomes for environment, local community and other users of TVI. Delivering on historical commitments and applying best practice to ensure the lease area can be relinquished as a functioning and sustainable ecosystem is key to being a responsible operator and maintaining social licence to operate. This paper will provide an overview of decommissioning activities and progress to date, with a focus on onshore operations, and discuss challenges encountered as well as lessons learnt from decommissioning planning and sequencing, implementation of the regulatory framework and in-field execution. To access the poster click the link on the right. To read the full paper click here
Ministerial Address
Authors: Pitt Keith
Published: June 2022

There is not an abstract available for this presentation. To view the video, click on the link to the right.
Electrochemical modulation enhances the selectivity of peripheral neurostimulation in vivo
Authors: Flavin Matthew T. , Paul Marek A. , Lim Alexander S. , Lissandrello Charles A. , Ajemian Robert , Lin Samuel J. , Han Jongyoon
Published: June 2022

Significance

Bioelectronic medicine relies on electrical stimulation for most applications in the peripheral nervous system. It faces persistent challenges in selectively activating bundled nerve fibers. Here, we investigated ion-concentration modulation with ion-selective membranes and whether this modality may enhance the functional selectivity of peripheral nerve stimulation. We designed a multimodal stimulator that could control Ca
2+
concentrations within a focused volume. Acutely implanting it on the sciatic nerve of a rat, we demonstrated that Ca
2+
depletion could increase the sensitivity of the nerve to electrical stimulation in vivo. We provided evidence that it selectively influenced individual fascicles of the nerve, allowing selective activation by electrical current. Improved functional selectivity may improve outcomes for important therapeutic modalities.
Cip1 tunes cell cycle arrest duration upon calcineurin activation
Authors: Flynn Mackenzie J. , Benanti Jennifer A.
Published: June 2022

Significance

To ensure their survival, cells arrest the cell division cycle when they are exposed to environmental stress. The duration of this arrest is dependent upon the time it takes a cell to adapt to a particular environment. How cells adjust the amount of time they remain arrested is not known. This study investigates the role of the phosphatase calcineurin in controlling cell cycle arrest duration in yeast. We show that calcineurin lengthens arrest by prolonging Hog1-dependent activation of the poorly characterized cyclin-dependent kinase inhibitor Cip1. Cip1 only impacts cell cycle arrest in response to stressors that robustly activate calcineurin, suggesting that Cip1 is a context-specific regulator that differentially adjusts the length of arrest depending on the particular stressor.
The aryl hydrocarbon receptor instructs the immunomodulatory profile of a subset of Clec4a4+eosinophils unique to the small intestine
Authors: Wang Wei-Le , Kasamatsu Jun , Joshita Satoru , Gilfillan Susan , Di Luccia Blanda , Panda Santosh K. , Kim Do-Hyun , Desai Pritesh , Bando Jennifer K. , Huang Stanley Ching-Cheng , Yomogida Kentaro , Hoshino Hitomi , Fukushima Mana , Jacobsen Elizabeth A. , Van Dyken Steven J. , Ruedl Christiane , Cella Marina , Colonna Marco
Published: June 2022

Significance

Eosinophils contribute to type 2 immunity against helminths and allergens. The small intestine harbors eosinophils with incompletely understood pathophysiological roles. Here, we show that intestinal eosinophils include two subsets. One expresses the inhibitory receptor Clec4a4 and the inhibitory ligand PD-L1 and is unique to the small intestine; the other manifests a proinflammatory phenotype. Both subsets are blood derived. Remarkably, Clec4a4+eosinophils were instructed by the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor that imprints many gut immune cells. Selective AHR deletion in eosinophils depleted Clec4a4+eosinophils, augmented innate lymphocytes producing type 2 cytokines, and enhanced helminth clearance. We conclude that Clec4a4+eosinophils have immunomodulatory functions, which could be harnessed for the therapy of food allergies and eosinophilic gastrointestinal disorders.
Structural modelling and quantitative analysis of mechanical gradient in CNT/Al composites
Authors: Zhou Lingxiao , Zhuang Qianduo , Min Xinrui , Liu Weijie , Yue Zhenming , Gao Jun
Published: June 2022

Carbon nanotube-reinforced aluminium normally considered to be composed of Carbon nanotube (CNT) free grain interior (GI) and CNT containing grain boundary affected zone (GBAZ). Research works showed that the property of GI varies with the distance from the boundary. To better understand the influence of this mechanical heterogeneity, we introduced a transition zone (TZ) to emphasise the mechanical heterogeneity of the GI. A dislocation-based plastic strain constitutive model was used to analyse the mechanical response, and the simulation results fit well with the experimental result. Moreover, the TZ thickness with a large simulation influence was found, and its strengthening mechanism, the influence of TZ thickness on the macroscopic mechanical response, geometrically necessary dislocation distribution were discussed in this study.
The influence of acoustic radiation force beam shape and location on wave spectral content for arterial dispersion ultrasound vibrometry
Authors: Capriotti Margherita , Roy Tuhin , Hugenberg Nicholas R , Harrigan Hadiya , Lee Hon-Chi , Aquino Wilkins , Guddati Murthy , Greenleaf James F , Urban Matthew W
Published: June 2022

Objective. Arterial dispersion ultrasound vibrometry (ADUV) relies on the use of guided waves in arterial geometries for shear wave elastography measurements. Both the generation of waves through the use of acoustic radiation force (ARF) and the techniques employed to infer the speed of the resulting wave motion affect the spectral content and accuracy of the measurement. In particular, the effects of the shape and location of the ARF beam in ADUV have not been widely studied. In this work, we investigated how such variations of the ARF beam affect the induced motion and the measurements in the dispersive modes that are excited. Approach. The study includes an experimental evaluation on an arterial phantom and an in vivo validation of the observed trends, observing the two walls of the waveguide, simultaneously, when subjected to variations in the ARF beam extension (F/N) and focus location. Main results. Relying on the theory of guided waves in cylindrical shells, the shape of the beam controls the selection and nature of the induced modes, while the location affects the measured dispersion curves (i.e. variation of phase velocity with frequency or wavenumber, multiple modes) across the waveguide walls. Significance. This investigation is important to understand the spectral content variations in ADUV measurements and to maximize inversion accuracy by tuning the ARF beam settings in clinical applications.
Conditional recurrence plots for the investigation of sawteeth pacing with RF modulation
Authors: Peluso Emmanuele , Murari Andrea , Craciunescu Teddy , Lerche Ernesto , Gaudio Pasquale , Gelfusa Michela , Gallart Daniel , Taylor David
Published: June 2022

In many areas of research, from neurobiology to nuclear fusion, which investigate complex dynamical systems involving numerous, different and interconnected physical quantities, the application of advanced analysis tools based on Chaos theory and Information theory has provided significant improvements both by supporting theoretical models and by highlighting hidden relationships between quantities characterizing the observed phenomena. The present article is therefore devoted to the analysis of synchronization experiments in magnetically controlled plasmas at JET, involving a ‘target’ quantity (sawteeth) and a ‘driver’ (modulated injected radio frequency) one. The typical approach to such analysis would start from assuming that the coupling between driver and target is free from external influences. However, since sawteeth can occur naturally and constitute a confounding factor in the analysis, by relaxing such an assumption a more realistic description of the system can emerge. The use of the conditional joint recurrence plots, complemented by the conditional transfer entropy, has provided further evidences supporting the effective influence of the pacing on the fast ions populations of both the minority and of the main plasma species in H-mode plasmas. The results highlight specific physical factors affecting the efficiency of the pacing and are in agreement with modelling estimates. The analysis performed then paves the way for future studies on more recent DT pulses performed at JET, and on data from other synchronization experiments.
Anisotropic diffusion as a proxy model for the estimation of heat-loads on plasma-facing components
Authors: Knieps A , Liang Y , Drews P , Endler M , Gao Y , Geiger J , Jakubowski M , Koenig R , Niemann H , Wang F Q , Xu S , Zhou S ,   The W7-X Team
Published: June 2022

To facilitate the estimation of heat loads on plasma-facing components in fusion devices in various different magnetic geometries, a heat load proxy model was developed based on anisotropic diffusion. In this work, this model is compared to the so-called field-line diffusion approach. To facilitate the evaluation of these models, a novel synthetic camera-based approach for obtaining heat load distributions from Monte Carlo samples was also developed and implemented. With the assistance of this synthetic camera, heat load predictions for the Wendelstein 7-X divertor were obtained and compared with infrared camera observations. It was found that the anisotropic diffusion-based model achieved a closer match to infrared camera observations, while still being suitable in computational effort for large magnetic configuration database scans.
A surrogate model of offshore wind farm annual energy production to support financial evaluation
Authors: Valotta Rodrigues Rafael , Friis-Møller Mikkel , Dykes Katherine , Pollini Nicolò , Jensen Morten
Published: June 2022

The preliminary financial evaluation of wind farm profitability requires fast analysis of energy production and costs while having very little specific information around the project. Early in the design process, the selection of specific wind turbines and the layout design may not yet be defined. Techno-economic and financial analysis models have been developed to use input from a small set of high-level project characteristics to estimate major cost elements and energy production for a wind farm to support quick analysis of levelized cost of energy (LCoE), or other financial metrics. Such models are typically based on prior project data and/or very simple analytical models. However, as capabilities for financial analysis of wind farms advance, so does the desire to improve the accuracy of the physical and cost modelling of the system. In this work, we develop a surrogate model of Annual Energy Production (AEP) for offshore wind farms for financial analysis applications in the early stages of development. The surrogate is developed from an parameterized engineering model and covers a large potential wind farm design space addressing different technological and site conditions. The surrogate model uncovers the underlying structure in the model in terms of input-output relationships and achieves a coefficient of determination of 0.994. The method used to develop the surrogate model can be adapted for additional dimensions of inputs as needed.
Identification of large-scale atmospheric structures under different stability conditions using Dynamic Mode Decomposition
Authors: Alcayaga Leonardo , Larsen Gunner Chr. , Kelly Mark , Mann Jakob
Published: June 2022

We investigate the characteristic of large-scale coherent motions over a large horizontal domain using the Dynamic Mode Decomposition (DMD) spectral analysis algorithm applied on measurements from two long-range pulsed lidars. We show the results and advantages of this methodology on six cases representative of three thermal stratification conditions at two heights relevant for wind energy: near-neutral, unstable and stable stratification at 50m and 200m above ground level. For these cases the DMD algorithm show three types of structures: streaks near the surface for near-neutral for neutral stratification, large-scale convective rolls for the unstable cases and sheet-like rotational patches for stable conditions. The DMD algorithm also shows the stationary effects of the terrain on the flow at 50m above ground level, within the atmospheric surface layer. The possibility of isolating terrain effects from coherent motions makes DMD attractive for studying complex atmospheric flow phenomena as well as to have more realistic input for wind farm flow simulations.
Farm blockage model validation using pre and post construction LiDAR measurements
Authors: Jacquet C , Apgar D , Chauchan V , Storey R , Kern S , Davoust S
Published: June 2022

This study discusses the characterization of farm blockage for an Onshore site. A test campaign was designed to measure the effects of farm induction upstream of a row of turbines. 5 LiDARs were dispersed on a site in North America. Measurement periods took place before and after erection of the turbines. A thorough characterization of the wind conditions is performed using the measurement from the pre-construction period. During nighttime, vertical profiles reveal the occurrence of low-level jet (LLJ) structure, and LiDAR-to-LiDAR horizontal variations in the measured wind speed are strong. Therefore, the analysis focuses on the daytime data only. Impact of farm blockage is quantified by analyzing variations of measured wind speed, relative to a LiDAR of reference, between the pre- and post-construction periods. These wind speed variations measured by the LiDARs, therefore, give insights on how the flow is distorted upstream of the row of turbines, but also within the inter-turbine space in the row. Additionally, the wind farm is simulated using a new CFD-based engineering model for blockage. Simulation results show very good agreement with the measurements, demonstrating the ability of the model to capture the underlying physics. The last part of the paper discusses the range of applicability of the test campaign results and proposes ways to further improve farm blockage characterization.
Synoptic and mesoscale winds in the complex terrain of Perdigão
Authors: Coimbra I L , Palma J M L M
Published: June 2022

For modeling complex atmospheric flows in wind energy studies when employing a chain of models, it is necessary to guarantee accurate wind simulations in all models that make up the chain. With this aim, we evaluated the ERA5 dataset (synoptic) and Weather Research and Forecasting (WRF) simulations (mesoscale) of the wind over Perdigão, which will later serve as input to a microscale model. The Perdigão-2017 measurement campaign is one of the latest and largest experiments over a complex terrain, thus being a valuable dataset for the validation of atmospheric models. Previous long-term simulation studies in Perdigão did not employ a highresolution reanalysis dataset for boundary conditions, nudging techniques, planetary boundary layer (PBL) sensitivity analysis, nor did compare synoptic and mesoscale data against local measurements. Here we simulated the wind in Perdigão using WRF with two one-way nested domains (9-km and 3-km horizontal resolutions) during 45 days, evaluating five PBL schemes. ERA5 reanalysis was used as input to the mesoscale simulations and for the spectral nudging in WRF’s outer domain. Data from the top anemometer of a 100-m tower, located in Perdigão’s SW ridge, were employed as reference in the evaluation of ERA5 and WRF wind speeds and directions. The hourly-averaged 3-km WRF simulations showed wind speed errors of 2.22 m/s RMSE and −0.02 m/s Bias with the YSU PBL scheme. The approximately 31-km ERA5 dataset exhibited total errors of 2.22 m/s (−0.37 m/s) RMSE (Bias). We attributed the similar ERA5 total error to its smoother wind speed values compared to WRF’s, despite its coarser resolution, and not to its faithful representation of the wind in Perdigão. WRF overestimated wind speeds mainly between the NW and N sectors as a result of its misrepresentation of the NW mountain range. Despite ERA5 coarser resolution, its smoothed terrain did not seem to greatly affect the wind near the NW direction. Additionally, both ERA5 and WRF wind speed errors vary linearly with the measured wind speed.
Impact of Turbulent Time Scales on Wake Recovery and Operation
Authors: Hodgson E L , Aa Madsen M H , Troldborg N , Andersen S J
Published: June 2022

Enhancing wake recovery behind wind turbines has the potential to significantly improve the power production and efficiency of large wind farms. Rather than investigating turbine control strategies, floater motion or global turbulent quantities such as turbulence intensity, this work aims to study wake stability and recovery through a focus on the turbulent scales of the inflow. Using Large Eddy Simulations of a single turbine, sinusoidal streamwise forcing is applied to the inflow with a constant amplitude and mean flow velocity, but differing time scales between 80s and 140s. For all applied time scales the turbine wake is characterised by the rolling-up of the near wake into the periodic shedding of vortex rings, and an excitation of the applied forcing frequency resulting in velocity fluctuations in the wake several times larger than that at the inflow. For shorter time scales (80s - 90s) a more aggressive and earlier wake roll-up led to a shorter near wake region, faster overall recovery and significantly improved the expected power output from 6R downstream onwards. An inflow time period of 80s gave rise to more than a 50% increase in power output of a fictive downstream turbine placed at 14R downstream, compared to an inflow time scale of 140s.
How generalizable is a machine-learning approach for modeling hub-height turbulence intensity?
Authors: Bodini Nicola , Lundquist Julie K. , Livingston Hannah , Moriarty Pat
Published: June 2022

Hub-height turbulence intensity is essential for a variety of wind energy applications. However, simulating it is a challenging task. Simple analytical models have been proposed in the literature, but they all come with significant limitations. Even state-of-the-art numerical weather prediction models, such as the Weather Research and Forecasting model, currently struggle to predict hub-height turbulence intensity. Here, we propose a machine-learning-based approach to predict hub-height turbulence intensity from other hub-height and ground-level atmospheric measurements, using observations from the Perdigão field campaign and the Southern Great Plains atmospheric observatory. We consider a random forest regression model, which we validate first at the site used for training and then under a more robust round-robin approach, and compare its performance to a multivariate linear regression. The random forest successfully outperforms the linear regression in modeling hub-height turbulence intensity, with a normalized root-mean-square error as low as 0.014 when using 30-minute average data. In order to achieve such low root-mean-square error values, the knowledge of hub-height turbulence kinetic energy (which can instead be modeled in the Weather Research and Forecasting model) is needed. Interestingly, we find that the performance of the random forest generalizes well when considering a round-robin validation (i.e., when the algorithm is trained at one site such as Perdigão or Southern Great Plains) and then applied to model hub-height turbulence intensity at the other location.
How long can constant wind speed periods last in the turbulent atmospheric boundary layer?
Authors: Moreno Daniela , Friedrich Jan , Wächter Matthias , Peinke Joachim , Schwarte Jörg
Published: June 2022

The statistical characteristics of periods of constant wind speed in the atmospheric turbulent wind are investigated. Our hypothesis is that specific circumstances of these structures in the wind may lead to not yet identified phenomena on an operating wind turbine. Therefore, the characterisation in terms of their lengths, probability of occurrence and extreme events is the focus of this study. Two data sets from atmospheric wind are analysed. Our findings reveal that the statistics of constant wind speed periods depends firstly, on the precise definition of wind speed thresholds and secondly, on the degree of turbulence. Additionally, a comparison to wind time series generated with a standard model suggests that these structures might not be properly reproduced by standard wind field models.
Development of a dynamic wake model accounting for wake advection delays and mesoscale wind transients
Authors: Foloppe B , Munters W , Buckingham S , Vandevelde L , van Beeck J
Published: June 2022

With tip height often above 200 meters, currently installed wind turbines are increasingly interacting with the atmospheric boundary layer. Therefore, the research intends to develop a new dynamic wake model that considers weather transient inputs. The Flow Redirection and Induction in Steady State (FLORIS) framework has been proven to be a powerful wake modelling tool even though lacking dynamical effects. An extension of the FLORIS framework is presented in order to include wake advection delays between wind turbines, time-varying and spatially heterogeneous wind conditions. The so-called Observation Points (OPs) are generated at the rotor centre location. Following a Lagrangian approach, the OPs are convected downstream, along the wake of the wind turbine, defining the wake centreline. It is during this process that the dynamics of wind turbine wake and background flow field unsteadiness are included. Finally, using the same approach currently implemented for yaw-misalignment wake deflection, the wake is shifted to match the unsteady wake centreline. The developed model is validated against Large Eddy Simulation for unsteady inflow with variable wind turbine control and wake interactions. The new model is applied to a simulation of the Horns Rev wind farm with a sinusoidally time-varying wind inflow direction to show an hysteresis in the wind farm power extraction curve.
Analysis of wake properties and meandering under different cases of atmospheric stability: a large eddy simulation study
Authors: Jézéquel Erwan , Blondel Frédéric , Masson Valéry
Published: June 2022

Large eddy simulations (LES) with the solver Meso-NH are performed to analyse a single wind turbine wake. In the first part of this work, four algorithms to determine the instantaneous wake centre (wake tracking) from the literature are compared. A data-processing method is also proposed to improve the results of these algorithms. In the second part, three different atmospheric conditions are simulated to assess the effect of inflow conditions on the wake. The focus is on the 2-dimensional wake width, the maximum deficit, the maximum added turbulence and the amount of wake meandering in the lateral and vertical directions. The three formers are computed in both the Moving and Fixed Frames of Reference (MFOR and FFOR). Results in the MFOR are shown to be sensitive to the wake tracking algorithm, in particular for turbulence. The flowfield in the MFOR is found to be independent of atmospheric conditions for the two cases with similar operating conditions and length scales larger than two diameters of the rotor. The third case with lower length scales and turbulence intensity behaves differently.