3rd EAGE/SUT Workshop on Integrated Site Characterization for Offshore Renewable Energy
- Conference date: October 15-16, 2025
- Location: Melbourne, Australia
- Published: 15 October 2025
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Development of a Shear Wave Structure Exploration System for Floating Offshore Wind Farms
More LessAuthors Y. Matsubara, Y. Asano, T. Kamoshita and A. HiraideSummaryAs an offshore exploration system for floating offshore wind farms, we have developed a system to grasp the Vs structure up to 20 to 30 meters below the seafloor at depths of 50 meters or more. In order to conduct surface wave method on the seabed, we developed a seabed weight drop source and constructed a system that can observe surface waves by operating the source at the ends of ocean bottom seismometer array arranged in a line. Using this system, we carried out measurements at a test site in Japan at a water depth of 60m and confirmed that detailed Vs structure could be obtained down to 20m below the seabed.
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Development of 3D Ocean Current Observation Technology Using Coastal Acoustic Tomography
More LessSummaryHuman activities that utilize the ocean, such as increased vessel traffic, marine leisure activities, offshore platforms and drilling facilities, and more recently, offshore wind farms, are steadily on the rise. As a result, the risk of maritime accidents has also grown, leading to a heightened demand for comprehensive and multidimensional marine information to ensure safe maritime operations. Against this backdrop, acoustic tomography technology, which analyzes the travel time of underwater sound waves, is gaining global attention. This technology enables the analysis of ocean currents and sound speed using acoustic travel times. Since sound speed is closely related to factors such as water temperature, salinity, and depth, it also allows for indirect analysis of ocean temperature. Traditionally, the Doppler current profiler—based on the Doppler effect of sound waves—has been the most common method for observing ocean currents. In coastal areas, HF-RADAR systems are used to monitor surface currents over a wide area. However, each has limitations and advantages. In this context, by analyzing the travel times between multiple signal paths, Coastal Acoustic Tomography (CAT) is emerging as a promising technology capable of providing real-time, wide-area, three-dimensional observations of ocean currents and temperature distribution.
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Enhancing the Value of Legacy Single Channel Seismic Data for Marine Site Characterisation via UUHR Processing
More LessAuthors J. Miller, K. Jarvis, M. Hooke and A. FitzallenSummarySingle channel seismic data is routinely and cost effectively acquired during initial marine site characterisation for offshore windfarm development. This data is often/typically subject to a basic seismic processing flow. Our premise is that with the application of an advanced seismic (re-)processing flow, this data can yield high resolution sub surface data that can inform early indications of subsurface geology relevant to ground model considerations.
An alternative source of seismic data suitable for enhancement via advanced seismic reprocessing exists in multiple readily accessible archives, for example our employer has an archive database populated with multiple examples of single channel data acquired in Australian waters over the past 20 years. Other companies & government bodies also have such databases. These offer a very cost effective source of data for initial site characterisation / desk top studies.
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Accelerating Offshore Wind Site Characterization with Integrated 3D UHR Geophysical and Hydrographic Surveys
More LessAuthors A. McKay, L. Limonta, R. Ruiz, B. Caselitz and C. JansonSummaryGeophysical & geotechnical site characterization surveys for offshore wind (OW) can take multiple years. This sequential and iterative survey strategy is sub-optimal and ultimately unsustainable. We will show that an integrated geophysical and hydrographic survey incorporating Ultra High Resolution (UHR) 3D seismic data – utilizing advanced processing and imaging methods - to characterize the seabed & shallow subsurface is a viable way to both optimize the OW site characterization process and reduce the overall duration & cost.
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UHRS Inversion Techniques at Different Stages of Offshore Wind Farm Development
More LessAuthors E. Dalgaard and R. RossSummaryTo meet the global targets for wind power deployment by 2030—estimated to require over 2,000 GW of total installed capacity to stay on track for net-zero emissions by 2050 (IEA, 2023)—the industry must rapidly scale up the development of wind farms in a cost-effective and timely manner. A critical factor in achieving this is a robust understanding of subsurface conditions, including geotechnical parameters and design-relevant behaviors.
A key enabler in this process is the quantitative joint interpretation of ultra-high-resolution seismic (UHRS) data and geotechnical investigations, which can significantly enhance subsurface mapping accuracy and reduce uncertainties. This, in turn, supports better decision-making throughout the project lifecycle.
In this presentation, we will examine three recent and diverse offshore wind projects, illustrating the role of integrated ground modeling in various project phases:
- Early-phase projects with sparse, low-quality data
- Mid-to-late-stage developments characterized by dense, high-quality datasets Each case presents unique challenges and opportunities, shaped by data availability, project maturity, and decision timelines.
We will demonstrate how effective, quantitative ground modeling can support:
- Early and mid-stage design and planning of geotechnical campaigns
- Later-stage design processes, including robust uncertainty analysis and risk mitigation
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A ML Approach for Reliability-Based Design of Vertically Loaded Piles Using Sparse CPT Data
More LessAuthors M.R. Khodayari, N. Yousefpour, N. Bozorgzadeh and M. CassidySummaryCone penetration tests (CPT) provide tip resistance (qt) and sleeve friction (fs) profiles for pile design, but data are often sparse due to cost and access, creating uncertainty at untested locations. This study proposes a novel ML-based method for CPT probabilistic prediction at untested locations in layered grounds, incorporating CPT and soil type profiles. The method consists of: 1) soil classification at CPT locations with no borehole data available, 2) stratigraphy interpolation in between CPT locations, and 3) CPT probabilistic predictions for pile capacity evaluation using spatial coordinates and soil type as inputs. Simulated qt and fs data were generated using Random Field with five soil types and a defined correlation structure. Results showed that including soil type in addition to coordinates improved prediction accuracy for both qt and fs, with higher R² and lower errors compared to the coordinate-only model. Using the distribution of predicted CPT, the Unified CPT-based axial pile capacity method was applied to an assumed closed-ended pile, showing ∼30% reduction in CoV and ∼60% reduction in error at several untested locations. Overall, findings from simulated data indicate the potential of this ML-based approach; however, further validation is needed using real-world field measurements.
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Field Observations of Rock Bag Behaviour on Mobile Seabeds when used as Secondary Stabilisation
More LessAuthors J. Jorgensen, T. Griffiths, D. Carneiro, J. Clayton, F. Pistani, B. Thurstan, C. Primultini and K. XiSummaryRock Bags (RBs) are mesh bags filled with loose rock of typical offshore grading, commonly placed to stabilise and protect subsea assets such as cables, Cable Protection Systems, and offshore wind turbine foundations. These RB are installed on various seabed types across offshore wind farms globally, with 4 tonne to 12 tonne sizes usually installed. RBs are an attractive solution due to the flexibility in vessels that can be used to install them – in particular contrast to placement of loose rock. Recently, significant research efforts have been directed toward developing a deeper understanding of the hydrodynamic behaviour of these RBs used as secondary stabilisation. A number of works have also considered behaviour of RBs on mobile seabeds as scour protection. Further, meaningful project experience has been established with these RBs on mobile seabeds. This is particularly the case in the Taiwanese offshore wind zones, where highly variable surficial soil conditions include erodible soft silty mush (being a widely understood and highly standardized geotechnical term), sand, sandwaves and boulder fields. This abstract will highlight the application of RBs on mobile seabeds, observations on their behaviour including RB-seabed interaction, and provide a qualitative assessment of their potential benefits.
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Data-Driven and Probabilistic Approaches for Seabed Characterization using Free Fall Penetrometers
More LessAuthors P. Tafazzoli Moghaddam, N. Yousefpour, S. Chow and M. CassidySummaryFree-fall penetrometers (FFPs) enable rapid seabed characterization, but interpreting their data and relating it to soil properties remains challenging. This study employs Bayesian inference to quantify uncertainties in converting FFP measurements, such as acceleration and velocity, into quasi-static tip resistance. In parallel, a multilayer perceptron (MLP) model is trained using laboratory FFP tests in kaolin clay. Results demonstrate that Bayesian inference effectively optimizes semi-empirical equations for FFP data interpretation, even with limited datasets. Furthermore, the MLP achieves substantially higher predictive accuracy in estimating quasi-static tip resistance compared to conventional approaches.
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