Day 1 Mon, May 06, 2019最新文献

{"title":"Marine Seismic Source Characterization Using Fiber Optic Sensors","authors":"E. Alfataierge, N. Dyaur, Li-Chin Chang, R. Stewart","doi":"10.4043/29267-MS","DOIUrl":"https://doi.org/10.4043/29267-MS","url":null,"abstract":"\u0000 This laboratory study explores the geophysical imaging applications of a fiber optic sensing system in a marine environment, from fiber installed on pipes or casing to fiber laying on the floor. The most common application with fiber installed on casing is borehole seismic imaging. With fiber laying on the ocean floor, surface seismic imaging is a possible application. This is tested in a laboratory setting using a Distributed Acoustic Sensing \"DAS\" system, Fiber Bragg Grating \"FBG\" system, and a conventional geophysical hydrophone system. A setup is made using PVC pipes and a water-filled tank to simulate a marine environment, and the sensing systems were distributed along the pipes and on the tank floor.\u0000 Single mode telecommunication fiber was laid out on the tank floor and the pipes, which consist of a vertical pipe segment and a horizontal pipe segment. The pipes are connected to a water reservoir to allow flow from the reservoir through the vertical pipe then the horizontal pipe into the tank. An array of FBG sensors were distributed along the pipes and some were left floating in the water. A hydrophone array was secured to the vertical pipe segment and distributed along the horizontal pipe segment to make conventional geophysical imaging measurements. Seismic sources with different frequencies were used, a piezoelectric transducer was used to introduce higher frequency (ranging from 500 Hz to 25 kHz), and a hammer source was used with different material as broad frequency sources. The measurements made were compared across the sensing systems and the frequency response was used to evaluate the preservation of the source frequency signature on the sensing instruments.\u0000 The DAS system was sensitive to low-frequency ambient noise which made it difficult to see the frequency response of the seismic sources, however, it was useful in capturing the higher range of frequencies. The FBG system showed better results in capturing lower frequency signal but was limited by the high frequencies it could capture. Nevertheless, the captured high frequencies exceeded the frequency range of interest for seismic imaging but are useful for applications of wireless communication using fiber and PZT transducers. Therefore, both systems can capture the response of the seismic sources for imaging but with different noise sensitivity.\u0000 The results presented in this study indicate that a fiber optic sensing system can be used for seismic imaging in an offshore environment. Further tests are recommended in larger scale environments to confirm the findings of this study. The advantages of using a fiber optic sensing system are highlighted in this study. Finally, further applications to wireless communication via fiber optic sensors and high-frequency transducers are discussed.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83079538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Why Not Boosting? Uncover the True Value of Your Subsea Asset","authors":"M. Stenhaug, Hongkun Dong, M. Hjelmeland","doi":"10.4043/29407-MS","DOIUrl":"https://doi.org/10.4043/29407-MS","url":null,"abstract":"\u0000 The first subsea multiphase boosting system was installed in 1994 and it is today a proven technology with a global track record. In addition to bringing increased production and recovery, multiphase boosting may also reduce flow assurance issues, reduce project CAPEX and OPEX, improve operability and safety as well as reduce the greenhouse gas emissions when compared to gas lift, the default lifting solution.\u0000 A review of the evaluation process and drivers during subsea artificial lift evaluations over the last three decades indicates that in general only a few of the actual upsides of subsea multiphase boosting have been considered, suggesting that there is a need for a more complete overview of the advantages and an approach to uncovering and quantifying the actual value.\u0000 This paper discusses the different aspects of subsea multiphase boosting through a comprehensive list of tangible benefits that may support the field development decision process towards identifying the potentially significant and hidden value of subsea multiphase boosting. Referencing experience from more than 30 installations it also provides a historical summary of the various aspects of subsea boosting and which drivers were and were not considered during the decision making process.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86265597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AUV Integrated Cathodic Protection iCP Inspection System – Results from a North Sea Survey","authors":"Matthew Kowalczyk, B. Claus, C. Donald","doi":"10.4043/29524-MS","DOIUrl":"https://doi.org/10.4043/29524-MS","url":null,"abstract":"\u0000 The OFG AUV non-contact integrated Cathodic Protection (iCP) inspection system enables a fast and reliable approach to monitoring the state of cathodic protection systems on subsea pipelines. By measuring the electric field, the system monitors directly the change in electrical currents in the pipeline due to anodes or damage. This approach allows for improved monitoring of anode energy remaining, predicts anode end of life earlier than stab methods alone and pinpoints problem areas on the pipe that need attention. When combined with the camera imaging, multi-beam measurements, synthetic aperture sonar (HISAS), and chemical sensors, the OFG AUV iCP system provides a compelling set of measurements for pipeline cathodic protection monitoring and pipeline inspection.\u0000 The advantage of the OFG AUV iCP system over traditional ROV CP systems is the speed with which these surveys can be undertaken, coupled with the dramatic increase in sensitivity which is approaching 100 times the sensitivity of the traditional ROV CP survey systems.\u0000 Ocean Floor Geophysics (OFG) has a successful history of developing numerous magnetic and electric field instruments for ROVs, AUVs and deep-tow systems. Based on the success of these programs, and in collaboration with ISES Technical Services (ISES), OFG & ISES have developed an electric field measurement system which mounts onto a pipeline inspection AUV.\u0000 Initial testing of the system in 2017 on OFG's 3000m depth rated Hugin AUV \"Chercheur\" demonstrated that the intrinsic electrical noise of the \"Chercheur\" with motors and all survey sensors running, was well below the threshold needed to successfully measure CP signals from the AUV. This was further supported through the development of a first principles model of the electrical fields generated around a generic cathodically protected pipeline.\u0000 These supporting measurements and calculations led to the first operational field test of the system on a North Sea pipeline in April 2018. During these trials we were able to demonstrate the responsiveness of the system to the cathodic protection currents in the pipe at a variety of ranges and orientations up to 10 meters distance from the pipe. Furthermore, by performing repeated surveys of sections of the pipeline in both directions, we were able to confirm the repeatable detection of extremely small electric field gradient signals (less than 0.025μVrms/cm difference). The results show levels of sensitivity and detection hitherto unattainable using any other currently available CP survey method. These measurements were taken concurrently with all the other onboard survey sensors running, including the HISAS, Sub-bottom, Multi-beam, Camera system, and USBL, while running at the nominal survey speed of the vehicle of 3-4 knots.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77797537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subsea Smart Electric Control Unit for Building Smarter and Cheaper Subsea Hardware","authors":"M. York, Ben Alexander, Todd Holtz, A. J. Schroeder, J. Chitwood","doi":"10.4043/29639-MS","DOIUrl":"https://doi.org/10.4043/29639-MS","url":null,"abstract":"\u0000 Subsea production systems and processes are generally conducted using hydraulic and more recently electro-hydraulic controls. These systems have become complex and expensive to deploy, especially with increasing length of tie-backs, more deepwater installations and challenging environments. Electrically powered and controlled equipment has become the standard for onshore and topsides equipment. Developing a subsea electric control unit that is modular and easily packaged is integral to leveraging the benefits of electric monitoring and control into subsea production systems and processes, as well as many other intervention applications such as subsea chemical storage and injection. In addition to simplifying and reducing costs of these systems, the unit will be able to discern an end component's health and status providing an opportunity to adjust or modify the operation in-situ, and in some instances real-time as well as provide other benefits. New analytical techniques powered by advanced analytics and artificial intelligence (AI) are being developed to examine in greater detail the controlled equipment's operational status, infer its current state of health and even predict future performance and maintenance/repair needs. As more and more data are collected and analyzed, the predictability and accuracy of the analysis and prediction improves.\u0000 Coupling the newly developed all electric subsea controller unit described in this paper with advanced data analytics will lower operator costs and risks in subsea systems. the system presented herein has been designed as a simple, rugged and reliable piece of equipment based on years of experience with API RP 17H Class 2 torque equipment and variable speed subsea pumps. It utilizes serial communications with position limiting and has a closed loop speed/position control, torque control, and real-time torque limiting. The profiling feature helps establish valve and pump status, functionality and health monitoring. The tool is ideally suited for subsea application to 10,000 fsw for any application requiring up to 250 ft.-lbs. with position and variable speed control. Leveraging learnings from the nuclear industry and their regulators, this ‘spring-less’ unit includes an option for a ‘smart battery’ (Lithium ion) back-up for specified fail-safe positioning and monitoring. Technical specifications were driven by operator customers. A full set of Functional Design Specs (FDS) were developed as well as an Inspection and Test Quality Plan (ITP). Where practical, acceptance criteria were leveraged from API, ASME and other industry guidance.\u0000 A full-scale prototype unit has been built, tested and qualified with over 1 million cycles. The unit enables collecting sensed operating data from one or more end devices and one or more control end points, calculating and performing analytics, and reporting health and status of the one or more end devices and one or more control end points. It is currently being utilize","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78180117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digital Twin of Subsea Pipelines: Conceptual Design Integrating IoT, Machine Learning and Data Analytics","authors":"S. Bhowmik","doi":"10.4043/29455-MS","DOIUrl":"https://doi.org/10.4043/29455-MS","url":null,"abstract":"\u0000 Digital Twin is a new paradigm combining multiphysics modelling together with data-driven analytics. In recent years, it draws considerable interest from the oil and gas field operators due to lower oil prices to reduce the downtime due to planned or unplanned preventive maintenance in production field which cost several million in the operational cost (OPEX). The digital twin is an integrated system with low-cost IoT sensors to gather system data, advanced data analytics to draw meaningful insights and predictive maintenance strategy based on the machine learning algorithm to reduce preventive maintenance cost. Overall the digital twin act as a digital replica of the field asset which is monitored and maintained based on actual sensor data from the physical field using machine learning.\u0000 This paper will demonstrate the conceptual design of a digital twin of subsea pipeline system integrating the computational model, field sensor data analytics and predictive maintenance based on the machine learning algorithm. The computational model is first developed in the finite element (FE) model and calibrated by the field sensor data installed on the physical system.\u0000 The computational model will be used to predict any change of pipe behaviour due to sudden changes in loading due to high pressure, slugging or leak etc. The proposed digital twin model will assist the oil and gas field operators in minimizing the OPEX with predictive maintenance schedule when it's needed to avoid failure in the pipeline system.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82565080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of Cost-Effective Design Methods Using Hydrostatic Head for High Pressure High Temperature Applications","authors":"P. D. Pathak, N. P. Katsounas","doi":"10.4043/29413-MS","DOIUrl":"https://doi.org/10.4043/29413-MS","url":null,"abstract":"\u0000 Validation testing of the subsea equipment designed for HPHT applications using external pressures due to the hydrostatic head can be a challenge. This paper presents the tests performed to validate the design methods proposed in OTC-27891-MS. Use of a seawater hydrostatic head enables 15,000-psi-rated subsea equipment to higher than 15,000-psi applications without the additional costs related to developing new 20,000-psi-rated equipment. The design methods utilize the guidelines in technical report API Technical Report 17TR8 and load cases per API Technical Report 17TR12.\u0000 Three primary validation tests are presented—one to validate the pressure-containing equipment, one to validate the pressure-controlling equipment, and one to validate the equipment subjected to trapped air voids. To validate the pressure-containing equipment, a 20,000-psi valve block was pressure tested to internal pressure up to 25,000 psi, with application of 5,000-psi external pressure simulating 10,000-ft applications. The valve block was strain gauged at multiple locations including the body and the bolts. The strains predicted using the finite element analysis (FEA) methods are then compared to the strains evaluated from the tests. For the pressure-controlling equipment, a 15,000-psi valve was tested to 17,000-psi upstream pressure and 2,000-psi downstream pressure across the gate of the valve assembly, with 2,000 psi external pressure, for various operational load cases to monitor the effects on performance of the gate valve and the actuator mechanism. The final validation test was performed for stem seals of the gate valve assembly, which are exposed to trapped air voids. These are tested separately to their absolute working pressures higher than 15,000 psi per the API 6A Annex F test regime.\u0000 The tests for the pressure-containing equipment showed that the actual strains in the valve block and bolts correlated well with the FEA. For the pressure-controlling equipment, various upstream and downstream pressure combinations and functions were tested which showed that the effect is minimal on the actual performance on the gate valve and the actuator and that the pressure-controlling equipment can handle the various expected differential pressure load cases. The stem seal test increased their absolute working pressure rating. These types of tests provide good guidelines on what the typical subsea equipment manufacturers can perform to validate their equipment with similar design considerations.\u0000 The paper presents the various practical tests that can be performed to validate the verification analysis utilizing the external pressures due to seawater hydrostatic head. Validation is a necessary part of the design process and can be extremely expensive and nonfeasible for subsea equipment. This paper presents a practical approach for validating the design verification analysis for subsea equipment.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75761687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Creative Solution to Re-Establish Control of a Subsea Field with Failed Umbilical","authors":"Jiayou Mao","doi":"10.4043/29477-MS","DOIUrl":"https://doi.org/10.4043/29477-MS","url":null,"abstract":"\u0000 LH4-1 oil field is a subsea tie-back which was developed by CNOOC in 2012. After a short period of production, the subsea control umbilical started with low Insulation Resistance (IR) of its electric control quads. Extensive trouble shooting work immediately started. The trouble was identified to be on the main umbilical. The subsea electric control was swapped to the spare quad. After about a year, the spare quad also had zero IR. In order to resume the subsea control, feasibility of using the spare Medium Voltage (MV) power cable triads as control channel was studied immediately. The idea of using three core triad to establish dual communication channels with two frequency bands was thoroughly studied and it was found theoretically feasible. Originally the communication was one loop controls 4 wells, now with the new arrangement one loop controls 8 wells, 3-core with one as common return makes two loops. So the new MV cable communication configuration can still achieve subsea control with 100% redundancy. Subsea special bridge flyleads were designed and manufactured to convert the 70mm2 3-core MV flylead to 10mm2 4-core communication flylead. Offshore intervention work was done in 2014. After installation, subsea communication to all 8 wells was re-established as expected. The signal qualitywas much better that the original umbilical possibility due to the large MV copper cores.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76188046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geospatial Survey Tools for Planning, Processing, Visualizing, and Assessing Marine Magnetic Survey Data for Archeological Resources","authors":"J. Bright","doi":"10.4043/29274-MS","DOIUrl":"https://doi.org/10.4043/29274-MS","url":null,"abstract":"\u0000 \u0000 \u0000 Marine magnetic surveys are a commonplace tool for archaeologists to discover, document, and characterize ferromagnetic submerged cultural resources (SCR). It is difficult, however, to quantify the efficacy of a given magnetic survey in terms of actual detection thresholds and, therefore, accurately assess the presence or absence of archaeological remains throughout a given area. Similarly, survey planning methods and data visualization techniques are likewise challenging to approach quantitatively. To address these issues, the Bureau of Ocean Energy Management's Office of Renewable Energy Programs partnered with the National Park Service's Submerged Resources Center to conduct a field research program whereby known ferromagnetic archaeological sites were magnetically sampled to better understand their respective detection thresholds. Incorporating the results of these tests, the team developed a series of custom geospatial processing tools in ArcGIS to assist in quantifying the process of planning, processing, and describing marine magnetic surveys.\u0000 \u0000 \u0000 \u0000 Field testing operations, which took place in Biscayne National Park, involved executing pre-determined magnetic survey sampling patterns around known ferromagnetic archaeological objects of various vintage, size, and materials. Acquired data was then processed to yield specific values for the object's magnetic moment, the primary variable needed to quantify induced magnetic field strength and, therefore, a given object's spatial threshold of detection. These were, in turn, used to refine induced magnetic field models subsequently incorporated into magnetic survey planning tools, as well as geospatial processing methods scripted in Python to automate magnetic survey data integration, visualization, filtering, and post-acquisition assessment.\u0000 \u0000 \u0000 \u0000 Sampled SCR included modern period steel-hulled vessels, diffused debris fields containing numerous scatters of iron artifacts, iron cannon and shot, historic anchors, and wooden sailing vessels with iron components. This diversity of test sites encompassed an array of archaeological materials typically found in a marine environment. Information yielded insights into the relative magnetic field strength of each these materials and site types, allowing models of induced magnetic field strength to be further refined in terms of a targeted object's anticipated detectability during a given survey.\u0000 Four Python scripts were developed, including an Input tool, Generate Survey Boundary tool, Visualization tool, and Confidence Modeling tool. Collectively these scripts comprise the Magnetometer Survey V.1.0 toolbox, which integrates into ArcGIS via ArcToolbox. Once marine magnetic survey data is output from a data acquisition program, these Python scripts automate the remaining data processing and facilitate a quantitative QA/QC assessment based on user-defined parameters. As a result, marine magnetic surveys for archaeological resources can planned, e","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85987629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symbiotic Autonomy for Deep-Water Survey","authors":"Andrew Ziegwied","doi":"10.4043/29559-MS","DOIUrl":"https://doi.org/10.4043/29559-MS","url":null,"abstract":"\u0000 Coupling Long-Range Autonomous Underwater Vehicles (LRAUVs) with Unmanned Surface Vehicles (USVs) solves two of the key challenges associated with LRAUV missions: lack of real-time communication with the underwater asset and unbounded navigational error growth from dead reckoning. The coupling of LRAUVs and USVs effectively transforms the capabilities and accuracy of the LRAUV survey.\u0000 A premier supplier of Unmanned and Autonomous Marine Systems led this development project working alongside a world-leading research center and developer of LRAUV systems. These two organizations were assisted by a leading developer of subsea acoustic positioning, communications and sonar systems, and a developer of software solutions for autonomous systems.\u0000 The system architecture enables the USV to provide regular position updates to the LRAUV, removing the need for the LRAUV to surface from depth to update its internally calculated position. This cooperative localization scheme increases the efficiency and accuracy of LRAUV survey while reducing cost. The combination of the high-accuracy sonar systems on the LRAUV transiting close to the seabed and accurate position updates from the USV provides game-changing solutions for deep water surveys and Exclusive Economic Zone (EEZ) mapping globally.\u0000 Due to the endurance and autonomy, this combination also allows for the possibility of executing remote subsea operations from a shore-based location. Eliminating the need for large ships to accompany the LRAUV significantly reduces data acquisition costs.\u0000 The USV communicates with the LRAUV through two key methods: acoustics to provide short mission updates and positioning information, and optical communication technology to enable the system to upload the data from the survey sensors. With the data uploaded to the USV, it is then possible for the USV to process the data to enable summary data to be passed back through satellite or radio communications to a control center. In situations where data may indicate where gaps occur, or further investigation is required, an updated mission plan can be transmitted from the control center to the USV and then to the LRAUV. As onboard data processing techniques improve, the USV can be used to adaptively update the LRAUV's mission without human intervention.\u0000 This transition to autonomy will save costs, reduce risk, and increase flexibility across a range of applications, including mine countermeasures, weapons testing, hydrography, environmental science, security, and surveillance.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88383943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PISA Design Methods for Offshore Wind Turbine Monopiles","authors":"B. Byrne, R. McAdam, H. Burd, G. Houlsby, Chris Martin, Wjap Beuckelaers, L. Zdravković, D. Taborda, K. Gavin","doi":"10.4043/29373-ms","DOIUrl":"https://doi.org/10.4043/29373-ms","url":null,"abstract":"\u0000 This paper provides an overview of the PISA design model recently developed for laterally loaded offshore wind turbine monopiles through a major European joint-industry academic research project, the PISA Project. The focus was on large diameter, relatively rigid piles, with low length to diameter (L/D) ratios, embedded in clay soils of different strength characteristics, sand soils of different densities and in layered soils combining clays and sands. The resulting design model introduces new procedures for site specific calibration of soil reaction curves that can be applied within a one-dimensional (1D), Winkler-type, computational model. This paper summarises the results and key conclusions from PISA, including design methods for (a) stiff glacial clay till (Cowden till), (b) brittle stiff plastic clay (London clay), (c) soft clay (Bothkennar clay), (d) sand of varying densities (Dunkirk), and, (e) layered profiles (combining soils from (a) to (d)). The results indicate that the homogeneous soil reaction curves applied appropriately for layered profiles in the 1D PISA design model provide a very good fit to the three-dimensional finite element (3D FE) calculations, particularly for profiles relevant to current European offshore wind farm sites. Only a small number of cases, involving soft clay, very dense sand and L/D = 2 monopiles, would appear to require more detailed and bespoke analysis.","PeriodicalId":11149,"journal":{"name":"Day 1 Mon, May 06, 2019","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79596979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}